An Overview of Scientific and NACD other Information on Cannabis National Advisory Committee on Drugs NACD An Overview of Scientific and other Information on Cannabis

NACD National Advisory Committee on Drugs

3rd Floor Shelbourne House Shelbourne Road Ballsbridge Dublin 4 Tel: 01 667 0760 Web: www.nacd.ie email: [email protected] NACD 2004 An Overview of Scientific and other Information on Cannabis 1 Authors: Claire Collins Claire Mark Morgan September 2004 Johnny Connolly Dominique Crowley Editor: Mark Morgan Information Information on Cannabis An Overview of of An Overview Scientific and other and other Scientific 2 An Overview of Scientific and other Information on Cannabis NACD 2004 T each SunAlliance,SráidTheachLaighean,BaileÁthaCliath2, Sun AllianceHouse,MolesworthStreet, Dublin2, Government Publications,PostalTrade Section, © NationalAdvisoryCommitteeonDrugs2004 Foilseacháin Rialtais,anRannógPost-Tráchta, (Tel: 01-6476834/35/36/37;Fax:01-4752760). (Teil: 01-6476834/35/36/37;Fax01-4752760). 4-5 BótharFhaearchair, BaileÁthaCliath2, Government PublicationsSalesOffice, Arna FhoilsiúagOifigantSoláthair. Published bytheStationeryOffice. To Oifig DhíoltaFoilseachánRialtais, Designed by

4-5 Harcourt Road,Dublin2, be purchased directly from the Le ceannachdíreach ón or bymailorder from ISBN 0-7557-1968-9 nó trídanbpostó Baile ÁthaCliath Prn. 3068 Dublin € first impression 5 NACD 2004 An Overview of Scientific and other Information on Cannabis 3 51 73 79 91 18 41 vailability and Quality of Product on the Marketvailability and Quality of Product 51 Overview A of Information and Availability Knowledge, Perceptions and Patterns of UsePrevalence Characteristics and Behaviours of UsersIndicators of Health ConsequencesContext of UseConclusions Gaps in Knowledge 54 Cannabis and Cognitive PerformanceCannabis and Self-injurious Behaviour 64 Health of Physical Cannabis and Perception Cannabis Use and Educational Outcomes 57 Cannabis Use and Occupational Performance 68 Psycho-social Consequences of Cannabis Use of the Risks of Cannabis UsePerceptions Conclusions Gaps in Knowledge 72 73 79 84 82 87 85 88 90 92 Overview Overview Chemical and Pharmaceutical InformationHuman PharmacologyPharmacokinetics in HumansClinical ExperienceCannabis Use and EpilepsyDependence Potential in HumansConclusions Gaps in Knowledge 18 27 26 39 35 29 41 able of Contents able Psychological Consequences of Cannabis Use Dr Mark Morgan Chapter 3: Chapter 2: Epidemiological Evidence Public Health Risks of Cannabis Use: Collins Dr Claire The Pharmacological and Toxicological Effects of Cannabis of Effects The Pharmacological and Toxicological Dr Dominique Crowley Chapter 1: Biographies – Minister of StateForeword – Chairperson NACDForeword – AuthorsExecutive Summary 6 7 8 5 T 4 An Overview of Scientific and other Information on Cannabis NACD 2004 pedxII Mmeso ADa fJn 04129 128 MembersofNACDasJune2004 Appendix III: MembersofConsequencesSubCommitteeNACD Appendix II: T T T T T T T List ofTables: NationalAdvisoryCommitteeonDrugsCannabisOverview–Tender Brief Appendix I: Appendices: Mr JohnnyConnolly Criminological andSociologicalConsequencesofCannabisUse Chapter 4: be2 om fCnai 22 91 90 89 26 63 19 ESPAD (1999) Study:Perceived RiskofSubstanceUse able 7. ESPAD (1999) Study:AssociationofCannabis, able 6. ESPAD (1999) Study:AssociationofCannabis, able 5. Prevalence RatesofCannabis Consumptioninthe able 4. SummaryoftheEffects ofCannabinoids able 3. FormsofCannabis able 2. Properties ofSomeNaturalCannabinoids able 1. asi nweg 114 104 99 97 111 107 100 Gaps inKnowledge Conclusions Major Value ConflictsSurrounding theUseofDrug Social FactorsthatIncrease theProbability ofHarm The CannabisMarket Consequences ontheSocialBehaviourofUser Social ConsequencesfortheUser Legislation onCannabisinIreland Overview Cigarette andAlcoholUsewithVictimisation Cigarette andAlcoholUsewithAnti-socialBehaviour General PopulationofWestern Nations cetfcIfraino anbs123 T Scientific InformationonCannabis cnclAnxso ikAssmn udlns124 echnical AnnexesofRiskAssessmentGuidelines 113 121 97 NACD 2004 An Overview of Scientific and other Information on Cannabis 5 Dr Claire Collins Dr Claire DipStats PhD, MSocSc, BSocSc, background Consultants (SCRC). Her and Clinical Research of Social Director Dr Collins is the Research has been in the research Her recent statistics, public health and epidemiology. is in medical sociology, private in collaboration with both public and and public health, of health services research areas for of Research Director in the Rotunda Hospital and the She is also the Statistician organisations. Practitioners. the Irish College of General Mr Johnny Connolly BA (Mod) LDIP LLM with the Drug Misuse Officer employed as a Research Johnny Connolly is a Criminologist. He is include: drug markets, interests research current His Board. Division of the Health Research Research between drug use and crime, community policing and non-custodial sanctions. the relationship Dr Dominique Crowley Med Tox MB, BCh, BAO, MPH, FFPHMI, MFPHM, Dip has been in the research Her recent is a Specialist in Public Health Medicine in Ireland. Dr Crowley communication. She is a member of the public health, risk assessment and risk of environmental areas in the of the Chief Medical Officer the Office National Forum on Fluoridation, representing of the FSAI Scientific Sub-Committee on contaminants Department of Health, and is also a member and additives. Dr Mark Morgan MSc, PhD NT, College, Drumcondra, Dublin, is Head of the Education Department at St. Patrick’s Dr Mark Morgan educational disadvantage and substance of literacy, has mainly been in the areas His research Ireland. programmes. use, particularly the evaluation of prevention Biographies 6 An Overview of Scientific and other Information on Cannabis NACD 2004 Foreword –MinisterofState Minister ofStatewithresponsibility fortheNationalDrugStrategy TD Noel Ahern comprehensive report. Connolly, DominiqueCrowley andMarkMorgan, whoalsoservedaseditor, onthisexcellentand Officer -MsAileenO’Gorman. Finally, IwouldliketocongratulatetheauthorsClaire Collins,Johnny Drugs, inparticular, itsChairperson-DrDesCorrigan, itsDirector -MsMairéadLyons anditsResearch NACD andforalltheon-goingworkofmembersNationalAdvisoryCommitteeon As Ihavesaidonmanyoccasions,amalwaysgratefulfortheresearch andanalysisprovided bythe and oursocietywehavetorefute thenotionpromoted bysomethatcannabisisharmless. such amove.Theapproach wehaveadoptedinIreland is, Ibelieve,appropriate forourcircumstances use ofcannabisonthehealthgeneralpopulationhavetobeconsidered bythosewhoadvocate particularly theyoungandthosewhoare heavyusersofthedrug.Theconsequencesmuchwider as someotherdrugs,itcanhavemanydamagingeffects onthephysicalandmentalhealthofuser, shows thatcannabisisacomplexsubstanceand,notwithstandingthefactitnotasdangerous bringing togethertheavailableevidenceanddrawingconclusions,where possible.Ibelievethereport lend itselftosimpleandeasyconclusions.However, thereport provides aninvaluableservicein As thereport pointsout,thevastbodyofresearch ontheconsequencesofcannabisusedoesnot knowledge inthisarea Advisory CommitteeonDrugs(NACD)toundertakethisresearch inorder toimprove ouroverall consequences is,therefore, essential.Inrecognition ofthis,theGovernmentaskedNational the mostwidelyusedillegaldruginIreland. Knowingasmuchpossibleaboutitshealthandsocial implications forpublichealthsocietyandlawenforcement. Astheoverviewnotes,cannabisis terms ofthephysical,psychological,educationalandmentalhealthconsequences,aswell r I amhappytowelcomethisoverviewoftheavailableinformationoneffects ofcannabisuse.The eport isprimarilyconcernedwiththeconsequencesofcannabisuseforindividualandsocietyin NACD 2004 An Overview of Scientific and other Information on Cannabis 7 know from our general population survey that Cannabis drugs are the most widely used of the the most widely survey that Cannabis drugs are our general population know from

ith respect to areas where national work is necessary, some of the points noted in the report are some of the points noted in the report national work is necessary, where to areas ith respect eflected in the number of people experiencing problems and/or becoming dependent. problems eflected in the number of people experiencing We Dr Des Corrigan Chairperson NACD Foreword – Chairperson NACD – Chairperson Foreword the from scientific evidence about the drugs produced on the This report illegal drugs in Ireland. the most complex consumed by human among that they are Cannabis plant also demonstrates the by the plant through produced the chemical mixture extends from beings. This complexity The varied pharmacological parts of the human body. on so many different diversity of their effects in any listing of psychoactive drugs give them a unique place of Cannabis and psychological effects individual also many are there to categorise, difficult the drugs and their effects drugs. Not only are and influence their impact on those who use them and and societal factors which interplay with them community. on the broader have Connolly and Dominique Crowley Collins, Johnny and his co-contributors Claire Dr Mark Morgan job in capturing the complexities of the Cannabis drugs in all their manifestations. done a remarkable such a mammoth task and in particular for highlighting The NACD is grateful to them for performing specific areas in our knowledge of these drugs. The authors have also pinpointed more gaps broader to Cannabis. base relating our information need to improve we in Ireland where similar to are to which attention is drawn in this report areas It is noteworthy that many of the broader at EU level. For Cannabis being debated at present those mentioned in a Draft Resolution on Sixth Framework on Cannabis within the EU’s to the need for research instance, the Resolution refers health risks and calls on the EMCDDA, as the EU’s dependency and especially regarding Programme those using Cannabis intensively and/or in high dose are Drugs Agency to analyse how changes in r W published as Bulletin 3 of the NACD’s by the detailed analysis of Cannabis use in Ireland addressed use in us with some insights into Cannabis survey does provide While that general population survey. to on Cannabis decided to draw attention of its analysis of this report the NACD, as a result Ireland, on the Irish market; as well as establishing the the need to monitor the potency of Cannabis products between Cannabis use and mental ill- links are extent of Cannabis dependence, and whether there work is needed include a where significant areas Other illnesses in particular. health and respiratory and an study of what happens when Cannabis users come into contact with the legal system investigation of Cannabis use as one of the factors in early school leaving. it, but more from By highlighting what is known about the Cannabis plant and the drugs produced on individuals, families and communities, importantly indicating what is yet unknown about its effects the four authors have made an invaluable contribution to our understanding of Cannabis. in particular, I would like to thank all those who have contributed to making this publication happen, and and to the staff the report reading Ms Barbara Connolly for proof for editing; to Dr Mark Morgan members of the NACD for their comments on each draft. 8 An Overview of Scientific and other Information on Cannabis NACD 2004 Executive Summary term whichrefers tothepsycho-activepreparations thatderive from theplant Chapter 1examinesthepharmacologicalandtoxicologicaleffects ofcannabis.Cannabisisageneric Pharmacology andToxicological Effects based onthebroad consensus oftheevidenceavailable. evidence evenwhenitiscontradictory. Wherever itwaswarrantedwehavegivenourconclusions outcomes thatare sometimesattributedtocannabisuse.Whatwehavetrieddoispresent the frequently associatedwithbeginning tousecannabisandwhichmayhaveaninfluenceonthevery pinpoint. Evenmore complex istheissueofotherfactors(personality, socialfactors)whichare use ofothersubstances(legalandillegal)sothattheexactpartplayedbycannabisisdifficult to complex oneintermsofitschemicalcomposition.Inaddition,cannabisuseisoftenassociatedwith does notlenditselftosimpleandeasyconclusions.Thisispartlybecausethesubstanceavery It shouldbesaidattheoutsetthatvastbodyofresearch ontheconsequencesofcannabisuse also professionals inthepublichealtharea andjournalists, aswellthegeneralreader. published uptoearly2003.Theintendedreadership ofthisreport includesnotonlypolicymakersbut illegal, butwidelyusedsubstanceaffects arangeofoutcomes.Thisdocumentdrawsonliterature r as welltheimplicationsforpublichealth,societyandlawenforcement. Thestudydrawson concerned withthephysical,psychological,educationalandmentalhealthconsequences, This studyisconcernedwiththeconsequencesofcannabisuseforindividualandsociety. Itis cannabis atsometimeintheirlives(NACD&DAIRU,2003). Republic ofIreland showedthatclosetoone-fifthofthepopulationinislandasawholehadtried published findingsofasurvey8,442peopleagedbetween15and64inNorthernIreland andthe Cannabis isthemostfrequently usedillegalsubstanceinIreland andelsewhere. Therecently Overview r other hand,cannabisanditsderivatives seemtohavebeneficialoutcomesforcertaintypesof pain anecdotal reports cannotbereliably confirmedonthebasisofevidencecurrently available.Onthe that cannabismayhavebeneficial effects. However, scientificstudiesare inconclusive, andthe W establishing withcertaintyhowaspecific‘dose’ofcannabiscan reliably beadministered. to containingharmfulsubstancessuchasthosefoundintobacco smoke,there are problems in devoted totherapeuticapplications.Amongthedifficulties inestablishingoutcomesisthat inaddition potential therapeuticvalueofcannabiscompounds,whichin turn hasledtoanincrease in research development ofcannabinoid-baseddrugs.Forsomeyearsthere hasbeenadiscussionon the The chapterexaminestheevidenceonlegitimateusesof product, particularlywithregard tothe Medical Uses over recent yearsandthismerits monitoring. psychological andphysicaleffects. There issomeevidencethatthepotencyofcannabishasincreased contains 483chemicalsofwhichthemostimportantisdelta-9-THC,largely responsible forthe major concentrationoftheactiveconstituentsare locatedinthefloweringbudsofplant.Cannabis elevant research from Ireland andabroad withaviewtopresenting abalancedaccountofhowthis elief, treatment ofnauseaandvomiting appetite stimulation. ith regard tomooddisorders, anxietyanddepression, there isonlyanecdotalevidencetosuggest Cannabis sativa . The NACD 2004 An Overview of Scientific and other Information on Cannabis 9 Executive Summary Executive eward system. CB2 is not found in the brain but is located in the spleen and in blood-producing cells and in blood-producing system. CB2 is not found in the brain but is located in the spleen eward quickly and levels fall slowly as the drug is distributed to esult is that absorption into the body occurs It has frequently been suggested that heavy use of cannabis can induce serious mental illness. been suggested that heavy use of It has frequently hallucinations, ‘Cannabis psychosis’ involves symptoms that include a sudden onset of confusion, some studies is that patients’ mental a major weakness of disorientation and paranoia. However, is no there Furthermore, onset has not been well-documented. health prior to the apparent as ‘cannabis psychosis’. consistency in what is regarded and seems to survive strong is remarkably The association between cannabis use and schizophrenia indication of precise gives a more for confounding factors. Recent research applied are when controls the evidence that cannabis may precipitate is strong how cannabis influences the condition. There the risk of relapse cannabis use seems to increase illness among vulnerable individuals. Furthermore, Cannabis and Mental Illness Acute Effects state of consciousness characterised by mild of cannabis use include an altered The acute effects sensory experiences. alterations and the intensification of ordinary perceptual euphoria and relaxation, 3, a loosening of associations also results, to be discussed in Chapter As well as the cognitive effects In occasional users, the feeling and fantasy. enabling the user to become lost in pleasant daydreams for and this is a common reason reactions by anxiety and panic of euphoria can be replaced discontinuation of use. Many recent developments in the toxicology and pharmacology of cannabis have resulted from have resulted the toxicology and pharmacology of cannabis developments in Many recent cannabis on the brain. The of effects have concentrated on examining the laboratory studies which mimic the actions of cannabis and chemicals that act to block or receptors, discovery of two cannabis on human subjects. Two understanding of cannabis effects in a better has resulted on these receptors, in found predominantly are to date. CB1 receptors have been discovered types of cannabis receptors the brain within The highest concentration of these receptors the brain and in some peripheral tissues. and the perception pain movement and coordination, linked to learning and memory, is in areas r on is less certain and may have effect of CB2 receptors and other sites. The role in the bone marrow the immune function. and their associated endocannabinoids is extremely The existence of specific cannabis receptors alcohol, which does not have specific receptors. from significant in that it distinguishes the substance including of alcohol depend on non-specific interactions with a whole range of receptors The effects those for cannabis. alcohol. The highly fat-soluble – something that also distinguishes these drugs from Cannabinoids are r eliminated in the urine and down cannabis to compounds which are fatty tissues. The liver breaks up to four weeks after use in those who may be detectable in urine products faeces. These breakdown after use. Although four to six hours of cannabis usually wear off heavy users. The effects relatively are also take longer for them to eliminate cannabis it may quickly, metabolise cannabis more users chronic their system. and its metabolites from Cannabis Receptors 10 An Overview of Scientific and other Information on Cannabis NACD 2004 Executive Summary r who alsosmoketobacco,thattheymaybeatincreased riskofdevelopingcancer. Furtherstudiesare tobacco smokeare sufficiently strong towarrantadvisingregular cannabissmokers,especiallythose epidemiological evidenceisconflicting.Oneviewthatthesimilarities betweencannabisand The evidenceonthecancerrisksofcannabisuseisstilltooweak towarrantstrong conclusions. The decreased respiratory functionare foundinyoungcannabissmokers,independentoftobaccouse. have more symptomsofchronic bronchitis thannon-smokers.Specificallyrespiratory symptomsand tobacco, there are strong indicationsthatpeoplewhoare regular usersofcannabis,butnottobacco, It isofparticularinterest that,inadditiontotherisksforheavycannabissmokerswhoalso smoke smokers ascigarette smokersifacigarette ofcomparable weightissmoked. been estimatedthatuptofourtimestheamountoftarcanbedepositedonlungscannabis as tobaccosmoke,includingcarbonmonoxide,bronchial irritantsandcancerstimulatingagents.Ithas The smokefrom herbalcannabispreparations containsall thesameconstituents(apartfrom nicotine) Respiratory Effects cannabis use. occurs asanimmediateeffect ofuse.Anumberdeathsfrom cardiac problems havebeenlinkedto decrease inbloodpressure andheartratewithchronic use.Conversely, anincrease inheartrate There are indicationsofcardiovascular effects insusceptibleindividuals.Theseincludeaprofound Cardiovascular Effects could potentiallytriggerseizures insusceptiblepatients. may increase non-compliance withanti-epilepticmedications.Cannabisuseorsuddenwithdrawal proconvulsant effects. Cannabisusecantransientlyimpair short-termmemory, andlikealcoholuse, Cannabinoids havecomplexactionsonseizure activityandexertbothanticonvulsant Effects onEpilepticConditions unhappy bringsaboutcannabisusewhichinturnresults infurtherunhappiness). features ofadolescents’lives,althoughitmaywellbethatthere isareciprocal relationship (being adolescence. Partoftheexplanationmaybethatcannabisusearesult oftheother strong indicationsthatcannabisusecancomeaboutasaresult ofdepression, particularlyduring not clearandtheevidenceforacausalrole islessclearthaninthecaseofschizophrenia. There are people withoutsuchadiagnosis.However, theextenttowhichdepression isaresult ofcannabisuseis People withadepressive conditionare manytimesmore likelytobeheavyusersofcannabisthanare tends toexacerbatetheconditionofschizophrenia andtoprevent recovery. in personswithschizophrenia. Theevidenceisquitestrong thatcontinuedandpersistentcannabisuse among thosewhoalready havedevelopedthediseaseandmaybemore likelytoleaddependence studies havesuggested thatcannabissmoking inpregnancy mayreduce birthweight,includingone Reports oftheeffects ofcannabisonthedevelopingfoetus haveyieldedconflictingresults. Some Effects ofCannabisDuringPregnancy equired toassessmore effectively thecancerrisksof cannabisuse. NACD 2004 An Overview of Scientific and other Information on Cannabis 11 Executive Summary Executive The Diagnostic and Statistical Manual of Mental Disorders The Diagnostic and Statistical Manual of (American Psychiatric Association, 1994) presents criteria for the diagnosis of psychoactive (American Psychiatric Association, 1994) presents A high proportion of youth in Ireland (over three quarters of 16 year olds) say they know where to quarters of 16 year olds) say they know where (over three of youth in Ireland A high proportion It is of cannabis use as risky behaviour. perceive low proportions obtain the drug and relatively on Alcohol and other Drugs) study Schools Project (European that in the ESPAD particular interest risk than was to be a much greater of cannabis was perceived use (Hibell et al., 2001) regular occasional use, in all countries including Ireland. Perceived Availability and Risk Availability Perceived Public Health Implications: Prevalence of the to cannabis use and includes a review health risks related the public Chapter 2 addresses that chapter reveals epidemiological studies of health outcomes of cannabis use. The evidence in this most often seized in cannabis is the most easily accessible, the most widely used, and is the illicit drug particularly among adolescents and young adults. Its use is increasing, Ireland. having used cannabis in the last year in Ireland Among the adult population, just over 1 in 20 report with higher among those in the 15-24 age group, rates are (NACD & DAIRU, 2003). The prevalence the rates are However, 11.1% indicating that they had used the substance at some time in the last year. indicated of those in the 55-64 age group percent only a half of one much lower for older age groups; cannabis use are that they had used cannabis in that period. It is worth noting that while the rates of much lower than for alcohol and substantially higher than for other illicit substances, they are cigarettes. The criteria for dependence on a psycho-active substance include increased tolerance, withdrawal substance include increased The criteria for dependence on a psycho-active of use that influences other significant consumption and a pattern in controlling symptoms, difficulty often than once a week) run users (more life. Some studies indicate that frequent activities in the user’s a significant risk of cannabis dependence. (DSM-IV) including on the concept of the dependence syndrome substance dependence based largely consumption and a pattern of use which in controlling difficulty tolerance, a withdrawal syndrome, have identified what they called in other important activities. Some researchers leads to a reduction fails to find such outcomes. It is clear while other research ‘unequivocal markers’ of such dependence a clear does not provide research users run the risk of dependence, the current that while frequent of withdrawal patterns as is found for some other drugs e.g. opiates. picture Dependence Potential well-controlled study that found that this relationship remained after controlling for any confounding after controlling remained that this relationship study that found well-controlled is found, it is such an effect found in other studies and where this has not been variables. However, for adolescent evidence that gestation is shorter except is little to tobacco. There small compared that cannabis causes studies have found no evidence epidemiological mothers and controlled birth defects. weight, birth to support an association between reduced evidence is insufficient On balance, there to distinguish the influence difficult It remains syndrome. congenital anomalies, or sudden infant death the influences that might from factors such as nutrition and socio-economic status of other concurrent be attributable to cannabis use. 12 An Overview of Scientific and other Information on Cannabis NACD 2004 Executive Summary cannabis reduces perceived barriersandinhibitionsagainsttheuseofotherdrugs perceived factor maybethesocialcontext inwhichcannabisisusedandobtained.Itmaybethataccess to contributory factorintheprogression from cannabisto other substances.Animportantenvironmental complete picture. There is alsosomeindicationthatgeneticsusceptibilitytodrugsmay beatleasta progression tootherdrugs. There are indicationsthatthismaybepartofthestorybut notthe attachment are associatedwith earlycannabisuseandthatthesefactorsare themselvesinfluentialin One elaborationofthe‘gateway’hypothesisisthatsocialdisadvantage andlowlevelsofparental have anopportunitytousethem. of ‘exposure opportunity’,i.e.,cannabisusersare more likelytobeexposedotherdrugsandthus taking othersubstancesbutholdsthatthemediatinginfluences are notdirect includingtheconcept ‘stepping-stone’ hypothesis.The‘gateway’hypothesisacknowledges cannabisprimestheuserfor Some viewsofthelinkbetweencannabisandotherdrugsfavour a‘gateway’theoryoverthe substances incertainindividuals. exposed toTHCsuggestingthatlong-termuseofcannabismightenhancevulnerabilityaddictive cross-sensitisation withamphetamine andmorphinecanbeinducedwhenanimalsare repeatedly brain reward andwithdrawalprocesses inexactlythesamewayasotheraddictivedrugsbutalsothat inevitably touseofothersubstances.Emerging evidencesuggeststhatcannabinoidsnotonlyaffect including opiates.Sometimesitisargued thatthepharmacologicalproperties ofthedruglead One viewofthesefindingswasthatcannabisuseprovided ‘stepping-stones’totheuseofotherdrugs likely toprogress tootherdrugsthanare occasionalusers. of cannabisortootherillegalsubstances.Fourthly, itisknownthatheavierusersofcannabisare more Thirdly, itisknownthatmanyyoungpeopletryoutcannabisanddonotprogress toeitherheavyuse association betweencannabisuseduringadolescenceandsubsequentofotherillicitdrugs. substances, thevastmajorityhavebegunwithcannabis.Secondly, there isa strong statistical a numberofmattersare clear. Firstly, amongyoungpeoplewhohaveusedavarietyofillegal W Cannabis andUseofOtherDrugs significant thatonlyaminorityofyoungpeopleare introduced tocannabisbyastranger. friends are amuchmore significantinfluencethanare peers,eventhoseinthesameschool.Itisalso significant predictor ofthelikelihoodayoungpersonexperimentingwithsubstance.Close finding from Ireland andEurope. Thistiesinwiththefindingthatfriends’useofcannabisisa In about80%ofcases,youngpeopletryoutcannabisforthefirsttimewithfriends.Thisisaconsistent Initiation toCannabis the years. different from thatforalcoholandcigarettes where genderdifferences have tendedtodeclineover older ageofinitiationtocannabisthanboys.Itisinteresting thatthispatternofgenderdifferences is prevalence, recent usage(lastyear),andinproblems associatedwithuse.Furthermore, girlshavean Cannabis useismore prevalent amongmalesthanfemales. Thisdifference isfoundinlifetime Gender ith regard totherelationship betweencannabisuseandthesubsequentofother substances NACD 2004 An Overview of Scientific and other Information on Cannabis 13 Executive Summary Executive ith regard to cognitive functioning as measured by IQ and similar types of tests, there is little by IQ and similar types of tests, there to cognitive functioning as measured ith regard ole of cannabis in road traffic deaths is complicated by the fact that alcohol is also present in the fact that alcohol is also present deaths is complicated by the traffic ole of cannabis in road W cognitive functions, something which impairment of broad severe evidence that cannabis produces is a there structural changes in the brains of users. However, to find gross to the failure may relate subtle cognitive impairments of considerable body of evidence that heavy cannabis use produces to note that the of complex information. It is also of interest attention and the organisation memory, period of with a prolonged cases, the impairment can be reversed that at least in some indications are abstinence. of complex attention and the organisation that impairments of memory, therefore The indications are do not reflect heavy cannabis use but that these differences associated with information are Chapter 3 reviews the major psychological consequences of cannabis use including effects on of cannabis use including effects the major psychological consequences Chapter 3 reviews and social cognitive functioning, motivation, educational performance, occupational achievement for many of these factors but the associations of a pattern of outcomes strong are There behaviour. for many findings. is difficult interpretation Cognitive Functioning Psychological and Educational Effects Public Health Consequences While cannabis is due to overdose. no indications that cannabis is involved in deaths are There to other substances of drug users, it is always secondary sometimes found in the post-mortem results like opiates. accidental factor in drug-related an important direct The evidence indicates that cannabis is not of the causal assessment accidents. However, is one important exception viz. road deaths but there r likely to alcohol, cannabis is much more indications that when mixed with are majority of cases. There be a risk factor than when consumed alone. concentration of levels satisfactory ways in which the serious issues in field studies regarding are There experimental the most convincing evidence is from of cannabis should be determined. Consequently of their often aware the influence of cannabis are work. This evidence shows that drivers under such as unable to compensate for the loss of capability in some psychomotor skills impairment but are like accidents in the workplace, will be matters and related staying in lane. It is likely that this area, in the future. actively researched more access to such drugs. Another factor that may be involved in progression is personality make-up. is personality Another factor that may be involved in progression access to such drugs. try out cannabis as part of a adolescents may initially is some indication that non-conforming There to take risks than their or ready novelty-seeking may be more to use drugs, i.e they propensity broader the risk that they start to underestimate such positive experiences with cannabis peers; they may have of other illicit drugs. cannabis to from to the progression clear which of these factors contributes At the moment it is not including the operation of a variety of factors findings reflect other drugs. It may be that the ‘gateway’ and personality factors. genetic, environmental 14 An Overview of Scientific and other Information on Cannabis NACD 2004 Executive Summary to therelationship betweenpooreducationalachievementandcannabisuse. students suspendedfrom schoolare lesslikelytohaveaccessfurthereducation,thuscontributing more likelythantheirpeerstousecannabis,alcoholandotherdrugs.Itisalsoofinterest tonotethat suspensions/expulsions from school.Thosewhowere suspendedorexpelledwere found tobemuch One interesting pointemerging inrecent research isthatcannabisuseinvolvedinalarge numberof values including,possiblyschoolsuccess. complex involvingpersonalityfactors,embracinganalternativelifestyleandrejection ofconventional cannabis onmotivationagainappliesonlytoveryheavyuse.Itislikelythatthemediatinglinksare prolonged useofcannabison motivationalprocesses isespeciallyrelevant. However, theeffect of their cognitiveskills.Anotherfactormightbemotivation;theevidenceondamagingeffects of doubtful ifanyofthestudiesincludedmanyyoungpeoplewhoselevelusewassuchastodamage affect cognitivecapacitybut thiseffect comesaboutonlyafterintenseandprolonged usage.Itis Why thisassociationisfoundsoconsistentlyanimportantquestion.Asnotedabove,cannabiscan expectations andsupervision. still remains evenwhencontrols are appliedtoarangeoffactorslikesocialbackground, parental cannabis use.Itislikelythatpartofthisrelationship isduetootherfactors.However, theassociation school leavingisoneofthebestestablishedfindingsinliterature ontheconsequencesof A strong associationbetween cannabisuseandpooreducationaloutcomes,especiallyearly Early SchoolLeavingandExclusionfrom School sufficient toruleoutotherdifferences thatmayhaveexistedinadditionto,andpriorcannabisuse. and beingmore likelytobeindebt.However, itisnotclearwhetherthecontrols thatare appliedare of negativeeffects includinghavingapoorer employment record, beinglesslikelytogainpromotion syndrome. Theresearch showsthatevenincontrolled studies,cannabisuserssuffered from avariety (the ‘amotivationalsyndrome’). Recentstudieshowever, havefailedtofindclear-cut evidenceforthis It hasoftenbeensuggestedthatcannabisusersappeartobeapathetic,lethargic andunmotivated Cannabis andMotivation frequent cannabisuse. mediating theeducationalandoccupationaldifferences thatare alsoshowntobeassociatedwith permanent physiologicalchanges.However, thesecognitiveimpairmentsmaybeveryimportantin cannabis usewhichinturnsharpens thedifferences thatledtotheuseinfirstplace. outcomes there isevidenceofareciprocal relationship, i.e.certainpersonalitydifferences leadto be thatcannabisusersare lesswillingtopersistwithboring anduninteresting tasks.Asin manyother to personalitydifferences between cannabisusersratherthanuseperse.Forexample, itmay These differences are foundfairlyconsistentlybutthere are indicationsthatthisdifference maybedue lower income,greater jobinstability, andlowerjobsatisfaction. tends tobeassociatedwithsomewhatpoorer occupationalandemploymentperformance, specifically Given thedifferences withregard toeducationalachievement, itishardly surprising thatcannabisuse Occupational andEmploymentEffects NACD 2004 An Overview of Scientific and other Information on Cannabis 15 Executive Summary Executive elationship is not entirely clear and requires further study. clear and requires elationship is not entirely Legal Situation in Ireland to other differently has been treated of cannabis or cannabis resin since 1977, possession In Ireland a third From drugs. Possession for personal use is punishable by a fine on first or second conviction. a term of imprisonment up to 1 year on possession for personal use incurs a fine and/or offence, fine if convicted on indictment. This contrasts with years and/or a summary conviction and up to three for up the penalties associated with possession of any other drug which incurs a term of imprisonment conviction on to 1 year and/or a fine on summary conviction and up to 7 years imprisonment following indictment. Criminological and Sociological Effects Criminological and Sociological of cannabis use with a on the criminological and sociological effects Chapter 4 examines the research The 1961 United Nations and anti-social behaviour. between cannabis, crime focus on the relationship that the party to the convention to ensure Drugs obliges each Single Convention on Narcotics of cannabis extracts – marijuana, hashish and possession and distribution cultivation, manufacture, by the 1988 UN convention against the reinforced punishable. These obligations are cannabis oil – are Substances. Drugs and Psychotropic in Narcotic Illicit Traffic An analysis of the ESPAD data for Ireland (Hibell et al., 2001) shows that cannabis users are more likely more shows that cannabis users are (Hibell et al., 2001) for Ireland data An analysis of the ESPAD a fight having been involved in a range of anti-social behaviours (including bullying, starting to report not involved in cannabis use. It is also young people who were than were and damaging property) with also correlated and alcohol) are use (cigarettes worth noting that while legal forms of substance higher in the case of cannabis. are the correlations anti-social behaviour, associated with also those that are associated with anti-social behaviour are Since the factors that are some forms of between correlation is a weak but positive surprising that there victimisation, it is hardly for cannabis (or is not as strong that the association stressing victimisation and cannabis use. It is worth Related criminological issues are anti-social behaviour. indeed for legal substances) as is found for examined in Chapter 4. Anti-social Behaviour and Victimisation There is consistent evidence that young people attempting suicide are more likely to have a history of likely to have more young people attempting suicide are is consistent evidence that There is The first must be entered. two important qualifications others. However, are heavy cannabis use than invariably found in these cases, so misuse (legal and illegal substances) is almost that other substance point has to do with personality to pinpoint. The other of cannabis per se is hard role that the precise tend to be high risk- body of evidence that people using cannabis is a considerable make-up. There including self- of other behaviours involving danger, takers which in turn is associated with a variety pathway of this the precise use is associated with self-injury, Thus, while cannabis injurious behaviour. r Suicide 16 An Overview of Scientific and other Information on Cannabis NACD 2004 Executive Summary associated withthistrade. significant overlapbetweentrades indifferent drugsandthatasubstantiallevelofviolence is violence isassociatedspecifically withthetradeincannabis.However, theevidence suggeststhere isa adequate studiesintoIrishdrug markets,itisimpossibletostatewithanyclaritytheextent which Although there isclearevidenceofviolenceassociatedwith thedrugtrade,inabsenceofany being anactiveparticipantintheillegaleconomyofadrugmarket. this maybepartlyduetopredisposing factorsthatcausedthemtobeinvolvedwithcannabis orto than are nonusers,andindeed are alsomore likelytobevictimsofcrime(seeChapter 3). However, substance. There are indicationsthatcannabisusersare more likelytobeinvolvedincriminalactivities associated withcrimetogainpossessionofthenecessaryresources tocontinueacquire the that usersmaybecomeexcitableandirrationalasaresult ofdruguseormaybeinvolvedinviolence cannabis reduces aggressive impulsesandhasacalmingeffect ontheuser. Anotherviewsuggests There are conflictingviewsontheassociationofcannabisusewithviolence.Abenignviewisthat Cannabis UseandViolence number ofoffences inwhich criminalproceedings commencedin2002. Síochána 2000,2001,2002,2003).Cannabis-related offences accountedfor64percent of thetotal has increased steadilyfrom 4,185in1999to4,8802000 to 5,143in20015,5002002(AnGarda show thatthetotalnumberofcannabis-related offences inwhichcriminalproceedings commenced percent ofthetotalnumberdrugseizures forthatyear. Figures reported byAnGarda Síochána more seizures ofcannabisthananyotherdrug.In2002,cannabis-related seizures accountedfor54 Cannabis isthemostwidelytrafficked drugglobally. InIreland, asinmostothercountries,there are Seizures ofCannabisinIreland characteristics are especially importantwhentheconsequencesofcannabisuseare beinginterpreted. partners, andamongstudentswhoperceive religion and community serviceasnotimportant.These in otherhighriskbehaviourssuchasbingedrinking,cigarette smokingandhavingmultiplesexual cannabis ratherflowfrom it.Cannabisuseisalsofoundtobehigheramongstudentswhoparticipate been committedanyway. Manylongitudinalstudiessuggestthatcriminalitymayprecede theuseof those offences committedasaresult oftheusedrug asdistinctfrom thosewhichwouldhave between cannabisuseandacquisitivecrime,ithasbeendifficult toidentify, inthecaseofcannabis, offences thanare othersmalesofthesameageandbackground. However, withregards tothelink There isevidencethatmaledrugusers,particularly, are likelytocommitseveraltimesmore property Cannabis-related Crime and travelopportunities. have furtherproblems withthelawandproblems withemployment, accommodation,relationships that whileacannabisconvictionhadlittleimpactonsubsequentuse,significantminority cannabis possession,dependingonthecountryinvolved.There are indicationsfrom somecountries A varietyofeducationalandemploymentproblems comeaboutasaresult ofaconvictionfor Range ofConsequencesCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 17 . Executive Summary Executive Bulletin 1. The Diagnostic and Statistical Manual of Mental Disorders nnual Report 1999 Annual Report 2000 Annual Report 2001 Annual Report 2002 Drug use in Ireland and Northern Ireland. and Northern Drug use in Ireland APA, Washington DC. Washington APA, alue Conflicts Surrounding the Use of Cannabis alue Conflicts Surrounding eform remains one of the most contested areas of international drug policy. While it is beyond the of international drug policy. one of the most contested areas eform remains An Garda Síochána (2001). An Garda Síochána (2002). An Garda Síochána (2003). An Garda NACD & DAIRU (2003). American Psychiatric Association (1994). DSM-IV. M. (2001) Kokkevi, A. & Morgan, O., Bjarnasson, T., S., Balakireva, Hibell, B., Andersson, B., Alstrom, countries Alcohol and other drug use among students in 30 European report: The 1999 ESPAD Stockholm: CAN. Síochána (2000). A An Garda References V of cannabis by implementing policies which bring about a Concerns with limiting the effects with a number of other markets in other drugs have combined separation in markets for cannabis from On the other hand, strong to cannabis. approach factors to bring about a debate on the legislative The debate over cannabis law have been made to maintain the law as it is at present. arguments r listed contributions are scope of this publication to consider this debate in detail, some of the relevant in the final chapter. changes in cannabis law enforcement introducing to this debate by Many countries have responded very important, it is also While the legal statutes that exist are legal reforms. practices or through the impact some studies have considered applied. Although important to know how such laws are for further investigation. area an important of various legal changes, this remains The issue of the relationship between cannabis use and the subsequent use of other illegal substances between cannabis use and the subsequent use of other illegal The issue of the relationship It is well established that some people who use cannabis (the ‘gateway’ theory) was mentioned above. some indications as to what factors are do not. There go on to use other substances, while some may be that cannabis use brings the Part of the problem of such ‘progression’. the probability increase and involvement with harmful substances. Family problems user into contact with dealers selling more to other drugs. also involved in the progression deviant peers are Factors Increasing Probability of Harm Probability Factors Increasing There have been suggestions that because cannabis use has become such a routine feature of many feature use has become such a routine been suggestions that because cannabis have There people as a deviant form of behaviour. by such young lives, it is no longer regarded young people’s rate and the high prevalence relatively some people point to the As evidence of this ‘normalisation’, is evidence, There is common among their friends and peers. that such behaviour perception of social events and feature social contexts, that cannabis use is an accepted particularly in certain context of the such acceptance should be seen in the However, does not meet with outright rejection. dramatically at variance with which are age groups, views of the general public, especially older ‘normalisation’. ‘Normalisation’ of Cannabis Use ‘Normalisation’ 18 An Overview of Scientific and other Information on Cannabis NACD 2004 Effects ofCannabis The PharmacologicalandToxicological Chapter One Cannabis sativa Cannabis isagenerictermusedtodenotetheseveralpsychoactivepreparations oftheplant Chemical Description Chemical andPharmaceuticalInformation and reproduction itself.Issuesrelating tocannabisdependenceare alsoexaminedinthislastsection. depression. Othereffects considered includethoseontherespiratory system,thereproduction system cannabis onbrainfunctionwithparticularfocusmentalillnessincludingschizophrenia and and inhumansrespectively. Thefinalsectionofthechapterexaminesresearch ontheeffects of The secondandthird sectionsofthechapterare concerned withtoxicology/pharmacologyinanimals This chapterinitiallysetsoutthebasicchemicalandpharmaceuticalinformationoncannabis. Overview to varywidelydependinguponthevarietyandgrowing conditions. tetrahydrocannabinolic acid.TheTHCcontentandthecannabinoidcompositionare known Cannabinoids alsooccurintheplantformofcarboxylic acidderivatives,e.g. delta-9-tetrahydrocannabinol (delta-9-THC)(ElSohly, 2002)(Table 1). cannabicyclol, andvarioustetrahydrocannabinol isomers,themostimportantbeing more than60cannabinoidsincluding: cannabinol,cannabidiol,cannabinolicacid,cannabigerol, Although acrudeplantproduct, cannabiscontainsacomplexmixture of483chemicals.Itcontains obtained bysolventextractionofthecrudeplantmaterialorresin followedbydistillation. plants are referred to as“sinsemilla”.Cannabisoil(hashishoil)isaconcentrateofcannabinoids has abrownish green colour, dependingondrynessandmaturityoftheplant.Theunpollinatedfemale The common“street” cannabis isusuallyamixture ofdriedflowers,leavesandoccasionallyseeds.It called “bhang”.Theresin from thebudsiscalled“hashish” andthiscanbescrapedfrom theplant. flowering buds.The“seed”orfruithasalowerconcentration.driedleavesandbuds(lessrich)are Although theactiveconstituentsare locatedinthewholeplant,majorconcentrationis New ZealandandMorroco. TheIndianvarietyiscultivatedintheOrient,AsiaandNorthAfrica. and NorthCentralAfrica.Majorproducers includeMexico,Brazil,Paraguay, Colombia,Peru, and Indiaeightcenturiesago.ItiscultivatedinNorth,CentralSouthAmerica,Asia,Europe, . Theplantisoriginallyfrom theCaspianandBlackSeaareas andwastakentoPersia Dominique Crowley NACD 2004 An Overview of Scientific and other Information on Cannabis 19 esponsible for psychological and physical esponsible for psychological Delta-9-THC. Does not interact with cannabinoid receptors. Not psychoactive but may enhance some THC. of effects for some Psychoactive and may be responsible of cannabis. of psychological effects Does not interact with cannabinoid receptors. Not psychoactive but has analgesic activity. Not structurally similar to cannabinoids. to mimic Appears Related to prostaglandins. actions of THC and other cannabinoids that interact with cannabinoid receptors Main properties largely Main psychoactive cannabinoid, r effects. Slightly less potent than Delta-9-THC but Only small amounts present otherwise similar. in plant. Little or no psychoactive properties. Does not interact with cannabinoid receptors. of and most other effects Lacks psychotropic Delta-9-THC, but has anti-epileptic activity. of May diminish some unwanted side effects The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The Chapter 1 Chapter cannabinoid receptors Natural metabolite of Delta-9-THC in the body Natural metabolite of Delta-9-THC in the Delta-8-THC-11-oic acid Natural metabolite of Delta-8-THC in the body Anandamine (arachidonyl ethanolamide) Endogenous ligand for mammalian Cannabichromene Natural plant cannabinoid 11-hydroxy-Delta-9-THC Arising from decomposition of THC Arising from Cannabidol Natural plant cannabinoid synthetic form Cannabinol Cannabinoid Delta-9-tetrahydrocannabinol in Available Natural plant cannabinoid. synthetic form as dronabinol Delta-8-tetrahydrocannabinol in Natural plant cannabinoid, also available able 1. Properties of Some Natural Cannabinoids (Adapted from Ashton 2001) (Adapted from of Some Natural Cannabinoids able 1. Properties T 20 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 1 some adverseeffects (BandolierExtra,2002). is notgreat andmore recent, thoughsmall,randomised trialsshowabsolutelynopositiveeffect, with (smoked ororal)benefitsspasticity from multiplesclerosis orspinalcord injury. Theweightofevidence by cannabisitself.There isonlylimitedevidence,mainlyfrom anecdotalreports, thatcannabis associated withspasticity, ataxiaandmuscleweakness,becauseverysimilarsymptoms canbecaused paradoxical thatcannabinoidsare reported tobeoftherapeuticvalueinneurological disorders conditions includingmultiplesclerosis, cerebral palsyandspinalcord injuries.Itissomewhat and dystonia(abnormalmuscletone),occursinanumberofchronic anddebilitatingneurological Muscle spasticity, withrecurrent painfulmuscle crampsandvariouscombinationsofweakness,tremor were likelytolimittheirwidespread use. serious adverseeffects suchasdizziness,dysphoria,hallucinations,paranoiaandlowblood pressure adjuvants forcontrolling chemotherapy-related sicknessinselectedpatients.However, potentially and vomitingTramer etal.(2001)concludedthatcannabinoids maybeusefulasmood-enhancing In theirreview oftheeffectiveness ofcannabisinthetreatment ofchemotherapyinduced nausea pain theyshouldnotbeused.Furtherstudieswere neededforspasticityandneuropathic pain. introduction intoclinicalpractice forpainmanagementwasnotindicated.Inacutepost-operative analgesics andhadCNSdepressant effects thatlimitedtheir use.Theauthorsconcludedthattheir pain, Campbellandhiscolleaguesfoundthatcannabinoidswere nomore effective than Codeineas r Systematic reviews oftheliterature fortheuseofcannabinoidsasanalgesicsandanti-emeticshave moderately supportiveofapotentialforcannabinoidsinthetreatment ofmovementdisorders. the NASreview, are musclespasticity, movementdisorders, epilepsy, andglaucoma.Animaldataare spectrum relief notfoundinanyothersinglemedication.Lesspromising categories,asdescribedin simultaneously from severe pain,nausea,andappetiteloss,cannabinoid drugsmayprovide broad- (NAS) (1999),forpatientssuchasthosewithAIDSorwhoare undergoing chemotherapy, andwhosuffer in arecent review ofthemedicalvaluemarijuanabyAmerican NationalAcademyofSciences potential indications,suchasforpainrelief, treatment ofvomiting andappetitestimulation.Asoutlined to newopportunitiesforthedevelopmentofsuchcannabinoid-baseddrugs.Thesedrugscouldhave Recent advancesintheunderstandingofwayswhichcannabisaffects thebodyhavegiven rise consumption ofcannabis. cannabis forcontrolled deliverywhilstavoiding,tosomedegree, theuncertaintyattachedwith As aresult, developmentsincannabinoid-baseddrugshavestrivedtoisolatethetherapeuticeffects of variable mixture ofbiologicallyactivecompoundsanddonotprovide aconsistentdoseorresponse. including mostofthosefoundintobaccosmoke.Anotherimportantfactoristhatplantscontaina In additiontoitsknownactiveconstituents,cannabissmokealsodeliversharmfulsubstances, an increase inresearch devotedtotherapeuticapplications. cannabis compounds,permittedtheirwideruseinthetreatment oforganic diseases,andhasledto Convention onPsychotropic Substances1971.Thiseffectively recognised thetherapeuticvalueof r In a1991report, theWorld HealthOrganisation ExpertCommitteeonDrugDependence Legitimate UsesoftheProduct ecently beenpublished(Campbelletal.,2001,Tramer etal.,2001)Inrelation tomanagementof ecommended thatTHCandrelated compoundsberescheduled from schedule1to2ofthe The PharmacologicalandToxicological Effects ofCannabis NACD 2004 An Overview of Scientific and other Information on Cannabis 21 The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The Chapter 1 Chapter lease of endogenous substances causing asthma (e.g. SRS-A), rather than inhibiting their activity lease of endogenous substances causing asthma (e.g. SRS-A), rather than inhibiting eductions of intra-ocular pressure (Robson, 2001). Conjunctival engorgement and tear reduction were and tear reduction (Robson, 2001). Conjunctival engorgement eductions of intra-ocular pressure eye in the untreated though parallel reductions with minimal side effects, reduction elated pressure A double blind, randomised, placebo-controlled crossover study using the synthetic cannabinoid study using the synthetic crossover placebo-controlled A double blind, randomised, in dystonia (Fox et al., 2002). significant reduction Nabilone showed no at the question of will look specifically use in multiple sclerosis UK-based study of cannabis A large components, can help the muscle either whole plant extract or one of its active whether cannabis, as be available later in likely to Results are sufferers. sclerosis multiple spasms that affect and stiffness 2003 (BMJ, 2001). Select Committee (1998), in addition to Science and Technology by the House of Lords As reported deal of anecdotal evidence to suggest that cannabis may have a is a great the above uses, there scientific The evidence from depression. such as mild anxiety or on mood disorders beneficial effect time. confirmed at the present cannot be reliably reports studies is inconclusive, and the anecdotal of such psychological stated that the human studies which have been cited in support The report homologues, or failed to use the double-blind benefits either used synthetic cannabinoid bias in the experimenters to eliminate possible experimental methodologies now required or subjects. of an adjunct to the treatment of asthma, and as treatment Other possible medical uses include in the Select Science and Technology (The House of Lords opiate and alcohol withdrawal syndromes Committee, 1998). studies in volunteers with of asthma, small-scale controlled to its use in the treatment In relation THC has comparable airway dilation activity asthma show that oral, smoked and aerosolised in increases Dose-related to salbutamol, although onset is quicker with the latter. (bronchodilation) higher doses. A THC aerosol in some individuals, and subjective intoxication with heart rate occurred but was irritant to the lungs (Robson, 2001). Nabilone does not of systemic unwanted effects, was free of the that the action of THC may involve suppression It has been proposed bronchodilation. produce re Select Committee, 1998). Science and Technology (The House of Lords glaucoma symptoms and individuals have suggest that cannabis may relieve Anecdotal reports for legal access to the drug (Robson, 2001). Randomised controlled in the USA successfully argued dose-related trials in volunteers suggest that oral, injected or smoked cannabinoids produce r than cannabinol, while effective more are often noted. THC, delta-8-THC and 11-hydroxy-THC trial may develop on multiple dosing. A randomised control Tolerance cannabidiol was without effect. of similar magnitude following smoked THC along reductions in patients showed intra-ocular pressure dose- produced with “alterations in mental status” and rapid heart rate (Robson, 2001). THC eye drops r (also seen in animal models) suggested a systemic rather than local mode of action. established for any therapeutic application. of delivery have not been Optimal doses and routes Smoking the drug is generally not a viable option since is unreliable. Absorption by the oral route vomiting in patients who are and reliability advantages such as rapid onset, accurate titration of effects not be have to be set against the likelihood of lung irritation or damage. In addition, it may and rectal acceptable to most patients. Sublingual sprays or tablets, nebulisers and aerosols of delivery in the future. be feasible routes to administration may all prove 22 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 1 Committee, 1998). Othermethodsofsmoking withouttobaccoinclude“hotknives” where cannabisis user tosmokemore toachievethedesired “high”(HouseofLords ScienceandTechnology Select vaporisers testeddidperformsimilarly. MostwaterpipesabsorbedtoomuchTHC, leadingthe cigarette wasaseffective a methodofdeliveryasanythedevicestested.However, oneofthe A recent studyofwaterpipesandothersmokingparaphernalia foundthatanunfiltered cannabis the extractionisabout50%ofcannabinoidcontent. maintaining thesmokeinlungsfor20or30secondstomaximise theabsorptionofcannabinoids; allowing adeeperandprolonged inhalation.Theusualtechniqueconsistsofinhalingvery deeplyand with opium,where refrigeration byairorwaterreduces theirritativeeffects ontherespiratory airways, Cannabis canbesmokeddirectly orthrough smallpipesor“bongs”.Theyare similarto thoseused of lessormore thanrequired toachievethedesired effects. to theconsumptionofentire uncertaindosageatonce.Thiscaneasilyresult intheconsumption easily controlled byself-titration. Incontrast,eatingcannabis,whetherraworinpreparations, maylead eaten ordrunk.Itisalsoconsumedinsmall,discrete amountsoveraperiodoftime.Thedosageis several factors.Smokingcannabisproduces noticeableeffects farmore immediately thanwhenitis the HouseofLords SelectCommittee Report(1998),thepreference forsmokingmay bedueto Inhalation remains thecommonest wayofconsumingcannabis(Hall&Solowij,1998).Asoutlinedin Intravenous, etc.) Route ofAdministrationandDosage(e.g.,Oral,Inhalation, T presented belowinTable 2. The formsofcannabishavebeendescribedaboveinthesection‘ChemicalDescription’andare Pharmaceutical Form mild anxietyanddepression isnotindicated. currently beingevaluated.Therapeuticuseofcannabisinthetreatment ofglaucomaorasthmaandin the treatment ofmusclespasticityislesscertain,whileitsuseinthetreatment ofmultiplesclerosis is pain relief, treatment ofnauseaandvomiting,appetite stimulation.Theevidenceofbenefitfor In summary, cannabisanditsderivativescouldhavepotentialindicationssuchasforcertaintypesof able 2. Forms ofCannabis able 2.Forms ahs UA ei ertdb ln 10-20%THC Resinsecreted byplant Hashish (USA) ahs i rdc fetato y 15-30%THC THCcontent(variable) Product ofextractionby Bricks,cakes,slabs Hashish oil Cannabis resin (UK) Source ofthe1960sand1970s Driedleaves/flowers/stalks/seeds re (Both oftheaboveterms Cannabis (UK) Marijuana (USA) Form fer toherbalcannabis) The PharmacologicalandToxicological Effects ofCannabis rai ovns(sometimesupto65%) organic solvents of 1980sand1990s oencgrte(on) 6-20%THC(60-100mg/joint) Modern cigarette (joint) T aiinlcgrte(efr 1-3%THC(10mg/reefer) raditional cigarette (reefer) (Ashton 2001) NACD 2004 An Overview of Scientific and other Information on Cannabis 23 The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The Chapter 1 Chapter echnology Select Committee, 1998). esin, ranges from 2-8 per cent, although it may be as high as 10 to 20%. Sinsemilla, the unpollinated 2-8 per cent, although it may be as high as 10 to 20%. esin, ranges from The THC content in cannabis plant is typically in the range of 0.5 to 4 per cent (Huestis et al., 1992). It The THC content in cannabis plant is typically in the leaves, lower leaves, stems, and seeds of the plant. is highest in the flowering tops, declining the dried flowering tops and leaves from USA) is prepared Herbal cannabis (termed marijuana in the content in hashish, which consists of dried cannabis and has a THC content of 6 to 20%. The THC r up to 20%. Hashish oil may contain between 15% and 50% female plants, may have a THC content of in cannabis have been renewed THC content THC (Adams & Martin, 1996). Concerns regarding developments in indoor cultivation techniques. These developments have because of recent so-called ‘nederwied’, to concentrations as high as enhanced the THC content in Dutch cannabis, may Those who use these high potency products unclear. 20%. The health implications of this are risks of developing dependence, having accidents while driving or experiencing their increase users may be able to titrate their dose and regular psychotic symptoms (Hall, 1998). However, may be experience adverse effects disease and naïve users who the risks of respiratory decrease 1998). further cannabis use (Hall, from deterred which may vary in THC content A typical joint contains between 0.5 and 1.0 g of cannabis plant matter, amount of THC between 5 and 150 mg (i.e. typically between 1 per cent and 15 per cent). The actual being lost through estimated at 20 to 70 per cent, the rest in the smoke has been delivered 1996). The bioavailability of THC (the fraction smoke (Adams & Martin, combustion or sidestream in human herbal cannabis cigarettes from the bloodstream) which reaches of THC in the cigarette 5 per cent to 24 per cent. Given all of these variables, the actual from subjects has been reported dose of THC absorbed when smoked is not easily quantified. smoker may consume five or individuals, but a regular for two or three A single joint may be sufficient a “high” In terms of THC dosage as little as 2-3 mg of available THC will produce joints per day. more in occasional users while heavy users may consume up to 420 mg THC per day. The vapour number of combustion products. in the formation of a large Smoking cannabis results and the cyanide and nitrosamines, hydrogen oxides, carbon monoxide, phase consists of nitrogen and agents including phenols, cresols particulate phase contains many known cancer-causing acid, which lacks During smoking, tetrahydrocannabinolic (PAHs). hydrocarbons polynuclear aromatic is converted to THC, thus adding to cannabis potency. psychoactivity, with the use of consumption may be reduced that the harmful effects been proposed It has recently they an effect their doses based on how profound normally regulate potent cannabis. Users of more of “high” degree if a greater achieve rather than on the amount of cannabis consumed. Therefore, crushed between red-hot blades and the vapours inhaled, or a coal is left to smoulder and the smoke or a coal is left to smoulder and the blades and the vapours inhaled, crushed between red-hot of experimental some reports are inhalation. There or bucket before collected in a glass, bottle in clinical trials (IPCS, 1989). of cannabis solutions and of cannabinoids intravenous injection then enclosed, paper and tobacco on to a cigarette is commonly smeared Cannabis oil when smoked to As it is inconvenient in the paper. the material is rolled before is mixed with tobacco or a drop to use it in cooking. oil prefer smoke, many users of requiring is limited by the lipid (fat) solubility of THC and other cannabinoids, Use in oral preparations of is the risk into an edible form. The main problem use of fats or alcohol to emulsify the drug Science and slow to develop but can be intense (The House of Lords are as the effects overdose, T 24 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 1 these receptors, refer toPertwee (1997). r molecular basisfortheimmunosuppressive actionsofmarijuana (Ameri,1999).Thefunctionsofboth different inmakeuptothe CB1receptor inthebrain. Theexistenceofthisreceptor provides the spleen andinblood-producing cellsinthebonemarrow andothersites.TheCB2receptor isquite distributed inperipheraltissues(Pertwee,1997,1999).TheCB2 receptor isfoundpredominantly inthe In contrasttoCB1receptors, CB2receptors are notfoundinthecentralnervoussystem (CNS),butare r r including theperiaqueductalgray(PAG) andthedorsalhornofspinalcord. However, unlikeopioid r r and theiractionsatCB1receptors inthefrontal cortexandnucleusacumbensmayaccountforthe basal ganglia,substantianigra,andcerebellum are thought tomediatetheireffects onmotoractivity of cannabinoidonlearningandmemory. TheactionsofcannabinoidsatCB1receptors localisedinthe example, actionsatCB1receptors inthecortexandhippocampusare thoughttomediatetheactions in thoseareas inwhichcannabinoids are thoughttoproduce manyoftheircharacteristic effects. For the brain,thesesitesare notdistributedhomogeneously,ligand [3H]CP55,940.Within beingdensest determined byreceptor-binding studies andautoradiographicstudiesusingthecannabinoidreceptor in thebrainandsomeperipheraltissues.ThedistributionofCB1receptors inthebrainhasbeen cannabinoid receptors, CB1andCB2(Felder&Glass,1998).receptors are foundpredominantly The acuteeffects ofcannabinoids aswellthedevelopmentoftoleranceare mediatedby mechanisms ofactionthesesubstances. (termed agonistsandantagonistsrespectively) (Pertwee,1997).Muchremains unknownaboutthe discovery ofcannabinoidreceptors andsubstancesthatmimicblocktheactionsofcannabis mechanisms ofactionthesedrugs.Recentadvancesinthisresearch havebeenfacilitatedbythe in detail(Kumaretal.,2001;Ameri,1999).Mostresearch has concentratedonestablishingthe in bothanimalandhumansubjects.Two recent reviews describethepharmacologyofcannabinoids The toxicologyandpharmacologyofcannabiscannabinoidshasbeenthefocusmuchresearch T individual toanddoseisdifficult toquantify. in recent decadesmainlyduetoimproved cultivationtechniques. Theeffect ofcannabisvariesfrom used, withthefloweringtipshavinghighestconcentration.Thepotencyofcannabishasincreased ingredients intheproduct consumedbytheuserisdependentonpartsofcannabisplant ingestion beingalsofavoured, particularlyforcannabisresin oroil.Theconcentrationofactive In summary, inhalationremains themostfrequent modeofadministrationcannabis,withoral Committee, 1998). cannabis smokedtheloweramount(HouseofLords ScienceandTechnology Select proportionally. Thisreasoning hasresulted inthesuggestionthathigherpotencyof were obtainedfrom asmalleramountofcannabisthenthe amountsmokedwoulddecrease eceptors are notfullyunderstood.Foradetailedreview ofthepossiblemechanisms action through espiratory depression associatedwiththesecompounds. eceptors, CB1receptors are relatively sparseinthebrainstem,whichmayexplainlackof eceptors, likeopioidreceptors, are alsofoundinareas thatmodulatenociceptive(pain)processing, einforcing properties ofcannabinoids(Nakamura-Palaciosetal.,1999).ElevatedlevelsCB1 oxicology andPharmacologyinAnimals The PharmacologicalandToxicological Effects ofCannabis NACD 2004 An Overview of Scientific and other Information on Cannabis 25 The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The Chapter 1 Chapter eward pathways for repeated THC administration (Ghozland et al., 2002). Repeated exposure to THC THC administration (Ghozland et al., 2002). Repeated exposure pathways for repeated eward etrograde communication across hippocampal synapses to modulate GABA release. Additionally it has GABA release. hippocampal synapses to modulate communication across etrograde the key endocannabinoids are that anandamide and 2-arachidonylglycerol ecently been proposed Nutt and Nash (2002) reviewed recent studies of endogenous cannabinoids. These substances facilitate studies of endogenous recent Nutt and Nash (2002) reviewed r r mediator of as being a probable anandamide The Lancet (2001) reported involved in this process. show without the CB1 receptor of the endocannabinoid system. Mice bred the analgesic effects similar to those seen in cannabis intoxication and dopamine D2 activation, and it behavioural effects (Fritzsche, 2001). a model for schizophrenia has been suggested that this could provide Effects on the Central Nervous System on the Central Nervous Effects of the cannabis in inhibiting learning and memory has been investigated in several studies of The role agonists on the of cannabinoid receptor effects rat hippocampus (part of the brain). The inhibitory (Kim & reported were nerve cells in cell culture formation of new synapses between rat hippocampal antagonist. by a selective CB1 receptor reversed were effects 2001). These Thayer, developments in recent scientific evidence, report Nutt and Nash (2002), in their update of the on studies examining the of cannabis and cannabinoids. They report animal studies on the effects Recently Nava et al. exposure. and withdrawal following cannabis mechanisms of tolerance, reward (2 weeks) administration of of chronic to the effects (2001) found that rats did not become tolerant The performance in the T-maze. or on the altered delta-9-THC on hippocampal Ach concentration, receptor blocked by CB1 seemed to be independent of time of onset, and both were effects antagonists. changes in the rat hippocampus following chronic Lawston et al. (2000) demonstrated morphological similar to those agonist. The changes were administration of WIN 55,212-2, a synthetic CB1 receptor and seen after ischaemic or toxic damage. Interactions have been observed between cannabinoids mice do not show negative motivational effects systems. Dynorphin-deficient other neurotransmitter mediated by endogenous opioids are effects suggesting that these with tetra hydrocannabinol, also shown to be implicated in modulating were (Zimmer et al., 2001). Endogenous opioid receptors r (Cadoni et al., induces behavioural sensitisation not only to cannabinoids, but also to opioids in rats to THC in mice, and also enhances 2001). Co-administration of nicotine facilitates the acute response et al., 2002). tolerance and dependence (Valient may help exposure to delta-9-THC in rats following chronic responses The development of differential of effects to explain the observation that humans develop tolerance to many of the physiological 2000). et al., cannabis, but not its euphorigenic actions (Wu Certain cannabinoid receptor agonists such as nabilone and delta-9-THC are already used clinically used already are agonists such as nabilone and delta-9-THC receptor Certain cannabinoid loss of appetite chemotherapy and against AIDS-related from resulting against nausea and vomiting in the variety of available increase et al., 1995; Pertwee, 1997). The ongoing 1986; Beal (Hollister, development of therapeutic could well have a significant impact on the ligands cannabinoid receptor the suggestion that have led to already rat and mouse experiments Results from uses of cannabinoids. of therapeutic potential in the management antagonist SR141716A may have the CB1 receptor et al., 1996). The diseases (Terranova with ageing and/or neurological memory deficits associated ligands of endogenous cannabinoid receptor opportunity to modulate extracellular concentrations also exists. 26 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 1 T is extremely highcompared withothercommonlyuseddrugs. toxicity ofcannabinoidsisverylowandthedoseTHCrequired toproduce 50%mortality inrodents (Kumar, 2001)andispresented inTable 3below. AsoutlinedbyHallandSolowij(1998),theacute A summaryoftheeffects of cannabinoids isprovided inarecent review ofcannabisandcannabinoids Human Pharmacology r r perception andmotoractivity. Therole ofCB2receptors islesscertain.Thediscoveryofcannabis concentration ofCB1receptors withinthebrainoccursatsitesresponsible formemory, learning,pain located inthespleenandblood-producing cellsinthebonemarrow andothersites.Thehighest predominantly inthebrainandsomeperipheraltissues,whereas CB2isnotfoundinthebrainbut subjects. Two typesofcannabisreceptors havebeendiscovered todate,CB1receptors are found of cannabisonthesereceptors, hasresulted inabetterunderstandingoftheireffects onhuman brain. Thediscoveryoftwocannabisreceptors, andchemicalsthatacttoblockormimictheactions r In conclusion,manyrecent developmentsinthetoxicologyandpharmacologyofcannabishave eceptors havebeenidentified. eceptors isofparticularsignificanceinmakingcomparisonswithalcoholsincenospecific esulted from laboratorystudiesandhaveconcentratedonexaminingtheeffects ofcannabisonthe able 3.SummaryoftheEffects ofCannabinoids eedne btnnesnrm Rarely observedbuthasbeenproduced experimentally Dependence, abstinencesyndrome T GeneralisedCNS depression, drowsiness, sleep,additive Fragmentationofthoughts,mentalclouding,memory Heightenedsensoryperception, distortionofspaceand Effects oncognitionand Sedative effects Effects onperception fet nmtrfnto Increased motoractivityfollowedbyinertiaand impairment,globalimpairment ofperformance Effects onmotorfunction psychomotor performance Effect Euphoria, dysphoria, anxiety, de-personalisation, Psychological effects Central NervousSystem System nieei fet Inacutedoses, effect reversed withlarger dosesorchronic Similarinefficacy tocodeine Anti-emetic effects Analgesic effects lrneTo mostbehaviouraland somaticeffects includingthe olerance The PharmacologicalandToxicological Effects ofCannabis antagonists following prolonged intoxicationoradministrationof “high” withchronic use use, increased appetite weakness andmuscletwitching effect withotherCNSdepressants time sense,misperceptions, hallucinations aggravation ofpsychoticstates uncoordination, ataxia,dysarthria, tremulousness, NACD 2004 An Overview of Scientific and other Information on Cannabis 27 The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The secretion, increased obstetric risks increased secretion, tolerance develops spleen on prolactin of ovulation, complex effects suppression Chapter 1 Chapter EyeImmune system in lung and activity of bactericidal macrophages Impaired pressure intra-ocular Decreased Cardiac outputCardiac blood flowCerebral Breathing Airways obstruction use with chronic in the short term and decreased Increased oxygen demand output and myocardial Increased smoking Due to chronic coughing but doses depress Small doses stimulate, larger System System Cardiorespiratory Heart ratePeripheral circulation Effect and postural hypotension conjuctival redness Vasodilation, use with chronic with acute dosage, decreased Increased Reproductive systemReproductive sperm count and sperm motility in males, Decreased able 3. (continued) Summary of the Effects of Cannabinoids Summary of the Effects able 3. (continued) Absorption tract is almost complete. Peak blood levels and maximal effects the gastrointestinal Absorption from apparent occur later after oral administration than after inhalation (Cone, 1988). Symptoms become a peak after 2-3 hours (Schwartz, 1987; IPCS, 1989). within 30-120 minutes, reaching by smoking. In comparison to oral administration, with quickly when delivered THC is absorbed more appear in within 7-10 minutes; subjective effects achieved inhalation peak plasma concentrations are than 2-3 hours. for more persist 20 or 30 minutes but rarely system via the to the circulatory a small bolus of the drug that is delivered represents Each puff measuring the alveolar sacs of the lungs. Huestis et al. (1992) reported capillary bed surrounding Pharmacokinetics in Humans Effects on Ability to Drive and Use Machinery Effects impairment in cognitive and behavioural functions that may impair a dose-related Cannabis produces potentiated with concomitant alcohol intake are These effects driving or the operating of machinery. (Kumar et al., 2001) (see chapter 2). Interactions with Other Drugs and Medicines Interactions with Other Drugs barbiturates, antipyrine, and ethanol. The combination Delta-9-THC enhances the metabolism of This rate and arterial pressure. heart significantly increases of cocaine and cannabis reportedly toxicity cardiovascular situation and in high doses may cause severe combination in a non-controlled (IPCS, 1989). T 28 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 1 smokers metabolisedelta-9-THCmore rapidlythannon-smokers. apparent accumulation;thissuggests thatthepersistentmetabolitesare inactive.Chronic marijuana days orweeks(IPCS,1989)butrepetitive ingestionorsmokingoverweeksisnotfollowed by clinically- non-cannabinoid metabolites.Delta-9-THCanditsmetabolites persistinhumanplasmaforseveral similar metabolicpathway;themostimportantoneis11-hydroxy-delta-9-THC whichismetabolised to metabolite, 11-nordelta-9-THC acid.Around 80cannabinoidmetabolitescanbeidentifiedfrom a metabolism, firstlytotheactivemetabolite11-hydroxy-delta-9-THC, thentothemore inactive After oraladministrationbutnotafterinhalation,delta-9-THC undergoes first-passhepatic accumulate infattytissues.Theseare subsequentlyliberatedslowlyintothecirculation (IPCS1989). Delta-9-THC ismetabolisedbytheliver. Itisintensivelyfatsolubleandhighconcentrations Metabolism cannabis (Chiang&Barnett,1984). concentrations ofTHCandthephysiological,behaviouralperformancechangesproduced by and todeveloppharmacokinetic/pharmacodynamicmodelsthatestablisharelationship between measuring THCanditsmetabolitesinbiologicalfluidstissues(Kingetal.,1987;Gjerde, 1991), and pharmacologicaleffects. Thisobservationhasledinvestigatorstoimprove thetechnologyfor peak priortodrug-inducedeffects, leadingtoadissociationbetweenbloodconcentrationsofTHC physiological effects return tobaselinelevels46hoursafterusage.BloodconcentrationsofTHC uptake byfattytissues(Barnettetal.,1982;Barnett1985).Generally, behaviouraland penetration inthecentralnervoussystem,andtosubsequentredistribution ofTHCfollowingrapid The delaybetweenpeakbloodconcentrationsanddrugeffects are likelyrelated todelaysin Plasma levelsofTHCfallrapidlyasthedrugredistributes intofattytissueduetoitshighfatsolubility. Distribution minutes afterthelastpuff ofcannabissmoke. low (1.75percent)orhigh(3.55dosecigarette. Maximumeffects were recorded within4to6 found thatpeakeffects occurred at17.4+/-4.8and13.84.2minutesafterinitiationofsmokinga non-tolerant individuals,physiologicalandbehaviouraleffects appearrapidly. Huestisetal.(1992) puffs, spacing,holdtime,andlungcapacity, contributetothisvariance.Whencannabisissmokedby The dynamicsofsmokingsubstantiallyinfluencehowmuchthedrugisabsorbed.number et al.,1980;Perez-Reyes etal.,1982;Huestis1992). developed inexcessof100mg/ml,althoughthere wasconsiderableinter-subject variability(Ohlsson smoked cannabiscigarettes containing1.32,1.97and2.54percent THC,peakconcentrations smoking cannabiscigarettes (1.75percentto3.55THCcontent).Whenexperienced users detectable amountsofTHC(7to18mg/ml)followingasinglepuff ofcannabissmokeinindividuals the substancepresent from thebody)ofdelta-9-THCis3days.Plasmaconcentrations delta-9-THC chronic use,after4-5weeksofabstinence.Thehalf-life(amount oftimerequired toeliminatehalfofall in thefaeces.Metabolitescanbe detectedinurineeven2-3daysafteroneexposure and,incasesof Thirty-five percentofdelta-9-THC anditsmetabolitesare eliminated intheurinecompared with65% Excretion The PharmacologicalandToxicological Effects ofCannabis NACD 2004 An Overview of Scientific and other Information on Cannabis 29 The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The Chapter 1 Chapter elevance of these findings to human health is uncertain (Hollister, 1992). This is because of the very 1992). This is elevance of these findings to human health is uncertain (Hollister, Effects of Cannabis Use on Immune Function Effects the impair immune function in rodents, that cannabinoids Although animal studies have reported r have pointed to high dose of the THC used in the animal studies (Kumar et al., 2001). A few reports prospective Two but have not been replicated. of cannabis on human immunity the adverse effects homosexual men have shown that cannabis use is not associated with an studies of HIV-positive to AIDS complications. risk of progression increased suppress and by Roth et al. (2002) examined evidence that delta-9-THC can regulate review A recent receptor both cannabinoid that leukocytes express authors reported The human immune responses. Clinical Experience Acute Effects state of of cannabis use have been well described and include an altered The acute effects alterations, including time perceptual and relaxation, consciousness characterised by mild euphoria with sensory experiences, such as those associated distortion, and the intensification of ordinary and talkativeness eating, watching films and listening to music (Hall et al., 1994). Infectious laughter short-term such as impaired cognitive effects, also pronounced are There also commonly occur. daydreams memory and a loosening of associations, enabling the user to become lost in pleasant so that skilled activity of various kinds is also impaired time are Motor skills and reaction and fantasy. by users, the feeling of euphoria is replaced disrupted (Hall et al., 1994). In occasional frequently on the for discontinuation of use. Effects and this is a common reason anxiety and panic reactions by 20±50% within a few rapid heartbeat, with heart rate increasing system include cardiovascular when standing but not in decreases hours. Blood pressure to three lasts for up minutes; this effect the sitting position. and 11-hydroxydelta-9-THC fall rapidly (in a few minutes) due to their redistribution in the fatty tissues; due to their redistribution fall rapidly (in a few minutes) and 11-hydroxydelta-9-THC and gradual half-life of 30 hours due to the metabolism is a slow decline with a there afterwards (range 2.9 and 5.0 users to 4.1 days in chronic The half-life may be increased elimination of the drug. 1988). days) (Johansson et al., However, of urinary cannabinoids. for the presence been suggested as a reason Passive inhalation has for passive inhalation to order in required were that huge efforts reported Adams and Martin (1996) of urinary levels of cannabinoids. The authors concluded that measurement detectable produce solely for the purpose of determining whether an urinary levels of cannabinoids should be conducted considerable assessing impairment would require individual has used cannabis. Attempts at the last use. surrounding knowledge of the circumstances Absorption into the body occurs in contrast to alcohol, cannabis is highly fat-soluble. In summary, to down cannabis to fatty tissues. The liver breaks quickly and levels fall as the drug is distributed may be products eliminated in the urine and faeces. These breakdown compounds which are of cannabis The effects heavy users. use, in those who are detectable in urine up to four weeks after it quickly, users metabolise cannabis more four to six hours after use. Although chronic usually wear off their system. cannabis from may also take longer for them to eliminate 30 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 1 of cannabisuse. Furthermore intheDukeatal.studythere wasnorelationship betweenseverityofsymptomsandlevel used cannabisasawayofcopingwiththeirmentalhealthproblems, intheviewofkey workers. However, thematterofcauseandeffect remains. IntheGrahamandMaslinstudy, manypeople Maslin study. interesting wasthatthenumberusingcannabisinaseriouswaysimilartoforGrahamand an epidemiologicalcensusininnercityarea whichutilisedastandardised assessment.Whatwas in centralLondon.Ratherthanbeingbasedonkey-workerinformationhowever, thedatacamefrom nature ofco-morbidnon-alcohol substancemisuseamongpeoplewithseriousmentalhealthproblem This conclusionissupportedinastudybyDukeetal.(2001)whichsoughttoestablishtheextentand to make,somewhere between10-15%ofthesamplewere heavyusersofcannabis. This wasespeciallythecaseamongstmalesofmedianage30years.Whileaprecise estimatewashard UK. Itemerged thatnexttoalcohol,cannabiswasthesubstancemostcommonlyusedproblematically. workers onsubstanceuseamongpeoplewithsevere mentalhealthproblems ininnercityareas ofthe For example,arecently-published studybyGraham&Maslin(2002)soughtinformationfrom key to beassociatedwithmentalhealthproblems. Itisalsoremarkable thattheassociationisquitestrong. It isworthnotingthatinnearlyallstudieshaveexaminedtheissue,cannabisusehasbeenshown and cannabisuseisdescribed. cannabis useinprecipitating schizophrenia isreviewed. Finally, therelationship betweendepression Firstly, theevidenceregarding a‘cannabispsychosis’isexamined.Secondly, thepossiblerole of The relationship betweencannabisuseandavarietyofformsmentalillnessisexaminedbelow. Cannabis UseandMentalIllness This includeseffects onmentalhealth,cognitivefunctioningandbehaviour. (Seechapter3.) Recent studiesoftheeffects ofcannabisonaspectsbrainfunctionare describedbelow. Cannabis andtheBrain impacting onhumancell-mediatedimmunityandhostdefence. r increased inperipheralbloodleukocytesobtainedfrom cannabis smokers.Thissuggestscannabinoid type 1(CB1)andcannabinoidreceptor type2(CB2),andlevelsofmRNAencodingforthem are consumption onthegrounds thatmanyhadnoprevious psychiatricsymptoms.Theyalso pointedto disorientation andparanoia.The authorstooktheviewthatthissyndrome wasduetothecannabis had usedcannabisandsymptoms thatincludedasuddenonsetofconfusion,hallucinations, described 200patientswhohad beenadmittedtohospitalsinCalcuttaoverafive-yearperiod. All One ofthefirststudiesdescribing acannabispsychosiswasthatofChopra&Smith(1974),who Cannabis Psychosis an establishedvulnerabilitytopsychosis. Cannabis usemayincrease theriskofpsychoticdisorders andresult inapoorprognosis forthosewith Schizophrenia andPsychosis eceptor activationinvivo.Theauthorsreported thathabitualexposure toTHCappearscapableof The PharmacologicalandToxicological Effects ofCannabis NACD 2004 An Overview of Scientific and other Information on Cannabis 31 The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The Chapter 1 Chapter Schizophrenia between cannabis use and the onset of set of studies have examined the association A related soldiers major studies can be used to illustrate this. A study of over 50,000 Swedish Two schizophrenia. at age 18 cannabis use between self-reported the relationship et al. (1987) examined by Andreasson indicated that those in the next 15 years. The results years and being diagnosed with schizophrenia than twice as likely to be diagnosed with more who had tried cannabis at age 18 years were the the use of cannabis at age 18 years, the greater frequent the more Furthermore, schizophrenia. likelihood of being diagnosed with schizophrenia. the similarity between the symptoms in the patients and noted that the users of the most powerful the symptoms in the patients and noted the similarity between problems. the most severe forms of cannabis had have of cases, other studies in other cultures number contains the largest While the Indian study of psychotic have been reports of cannabis use. There similar outcomes as a result described broadly Zealand (Eva, & Knight, 1973) and New in studies of patients in the Caribbean (Harding disorders 1992). been criticised on several grounds. times, these studies of cannabis psychosis have recent In more onset has not patients’ condition prior to the apparent Attention has been drawn to the fact that as is no consistency in what is regarded is that there usually been well documented. Another criticism cases of of it may account for a very small percentage ‘cannabis psychosis’. If such a condition exists ‘psychosis’. that population have yielded results studies in the general well-controlled Nevertheless, some recently study longitudinal general-population on a three-year Os et al. (2002) report convincing. Van more are of persons and of 59 people in the Netherlands with a baseline diagnosis of 4045 psychosis free follow- at baseline, one-year follow-up and three-year Substance use was assessed psychotic disorder. of any level of psychotic the presence use predicted up. The study showed that baseline cannabis symptoms. A number of for psychotic the need for care symptoms as well as clinical assessment of than half of the diagnoses could be more Firstly, Os et al. study. in the Van other points emerged effect a much stronger was that cannabis use had apparently attributed to cannabis use. Another point than in those without such a diagnosis. psychotic disorder among those with a baseline diagnosis of the risk of both the incidence of suggestions that cannabis use increases Results confirm previous those with an established vulnerability to for persons and a poor prognosis psychosis in psychosis-free to the This is one of the most consistently found and important findings relating psychotic disorder. of cannabis consumption. effects that might have symptoms of schizophrenia of other drugs, and prodromal The possible causal role suggested as led to the use of cannabis, rather than cannabis triggering the psychosis have all been a longer 2000). However, 2000; Hall & Dagenhardt, possible confounding factors (McKay & Tennant, et al., 2002) confirmed earlier findings that of the Swedish cohort (Zammit follow-up and re-analysis In the New Zealand cohort cannabis, and not other drugs, is associated with later schizophrenia. not by age 15 or 18 were times or more individuals who had used cannabis three mentioned earlier, in at age 26, although they showed an increase disorder likely to have schizophreniform more (Arseneault et al., 2002). not schizophrenia) symptoms” (but “schizophrenia 32 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 1 abuse disorders. factor thatindependentlyincreases bothpatient’s vulnerability tomentalillnessandalsosubstance cannabis useandschizophrenia andtheysuggestthatconduct/personality disorders may reflect a childhood. Theauthorsdrawattention totheimplicationoffindingforassociationbetween to 10times)haveaproblem withcannabisusethanwere thosewhodidnothavesuch disorders in experienced childhoodconductdisorder oranti-socialpersonalitydisorder were muchmore likely(up The studyshowedthatpeoplewhosubsequentlywere diagnosedasschizophrenics andwhohad between childhooddisorders andsubsequentsubstanceusedisorders amongschizophrenic patients. common influenceswascarriedoutbyMueseretal.(1999).The studyexaminedtherelationship One studywhichsuggeststhattheassociationbetweencannabis useandschizophrenia reflects by useofotherpsychoactivedrugsorpersonalitytraitsrelating tosocialintegration. of developingschizophrenia, consistentwithacausalrelation andthatthisassociationisnotexplained On theotherhandZammitetal.(2002)concludethatcannabis useisassociatedwithanincreased risk developed thediseaseandmaybemore likelytoleaddependenceinpersonswithschizophrenia. illness amongvulnerableindividuals,increases theriskofrelapse amongthosewhoalready have developed thedisorder. Theevidenceismore inlinewiththeviewthatcannabismayprecipitate unlikely thatcannabisusecausesmentalillnessamongthosewhowouldotherwisenothave common factorsdonotexplaintheco-occurrence ofuseandillness.Theyalsoconcludethatitis The literature inthisarea hasrecently beenreviewed byDegenhardt &Hall(2002). Theyconcludethat substance use. r substance (mainlycannabis)misuse.Outcomemeasures includingtreatment compliance,utilisationof many instances.Theyconcludedthatasmallproportion ofschizophrenias are precipitated by of substanceabuseandschizophrenia wasstudiedandsuggestedthattheytendedtocoincideinvery to havealifetimehistoryofsubstanceabuseattheagefirstadmission(14%vs.7%).Thesequence people withafirstdiagnosisofthedisease.Peoplewere twiceaslikelycontrols More recently, Buhleretal.(2002)studiedtheprecipitation oftheonsetschizophrenia among232 were alsolesslikelytocomply withdrugtreatment. history. Hisresults showedthatthosewithahistoryofcannabismisusewere more likelytorelapse and patients withahistoryofcannabisuseandcompared themwithasimilarnumberwithoutsuch schizophrenia andtoprevent recovery. Forexample,Caspari(1999)followedup39schizophrenic There isaconsensusthatcontinuedandpersistentcannabisusetendstoexacerbatetheconditionof forms ofschizophrenia –aformthatwasdistinguishablefrom thoseinwhichitsusedoesnotplayapart. cannabis hadarole inanyoftheirlifehistories.Theyconcludedthatcannabisplayedarole insome A recent studyBersanietal.(2002)startedwithdiagnosedschizophrenics triedtoestablishwhether schizophrenia (Leroy etal.,2001). association hasbeenreported betweenacannabinoidreceptor type1polymorphismandasubtypeof an associationbetweentheuseofvarioussubstancesandviolenceinpatientswithschizophrenia. An and earlysymptomonsetwere riskfactorsforcannabisuse.Aliterature review (Soyka,2000)described of schizophrenia describedtwicetherateofcannabisuseasinmatchednormalcontrols. Beingmale An investigationbyHambrecht etal.(2000)intotherelationship betweencannabisuseandtheonset ehabilitative measures andrateofemploymentwere poorer forpatientswith,thanwithout,early The PharmacologicalandToxicological Effects ofCannabis NACD 2004 An Overview of Scientific and other Information on Cannabis 33 The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The Chapter 1 Chapter esults are not absolutely clear-cut, it emerged that those participants who had a diagnosis of cannabis that those participants it emerged not absolutely clear-cut, esults are The coexistence of cannabis abuse and anxiety and depression is reported to be relatively common in relatively to be is reported abuse and anxiety and depression The coexistence of cannabis to which psychiatric the degree populations (Thomas, 1996). However, clinical and community substance abuse, or vice versa, is not risk factors for predisposing are such as depression disorders adults studied in both adolescents and These associations have been recently certain (Frances, 1997). male all studies have found an association in et al., 1998) although not (Rey et al., 2001, Troisi use was associated et al. (2001) found that cannabis 2000). Degenhardt & Ritter, participants (Green neuroticism but the association was explained by demographic factors, levels of with mood disorder, cannabis to self-medicate their dysphoria. and use of other drugs. Individuals may use and between depression relationship examine the reciprocal One of the few studies that attempted to sought to examine the extent study by Bovasso (2001). This longitudinal study cannabis use is a recent at Time symptoms to which cannabis use at Time subsequent depressive 2 (15 years later) 1 predicted at Time cannabis use at Timeand also the extent to which being depressed 1 predicted 2. While the r symptoms at the follow-up even likely to have depressive four times more abuse at baseline were In contrast, and anti-social behaviour. applied for age, social background, were when controls symptoms at Time use at the follow-up. While this design is not cannabis depressive 1 did not predict the view that cannabis in line with much more of this particular study are the results without problems, view. is a risk factor as opposed to the self-medication by Patton et al. (2002). Cannabis use examined of cannabis use in adolescence was recently The effect with daily users and anxiety, later depression to predict in adolescence, particularly girls, was reported to the according in higher rates of anxiety or depression carrying the highest risk. This was reflected later marijuana use and did not predict with which cannabis was used. Baseline depression frequency support the self-medication hypothesis. do not the results therefore, did not find an association between cohort study in New Zealand, the investigators In a recent at the age of 26 (Arseneault et al., 2002). disorder cannabis use at the age of 15 and depressive likely more by the age of 18 were times or more young people who had used cannabis three However, for. at the age of 26, even after use of other drugs was controlled disorder to have a depressive of long-term use of cannabis on depression. Considerable attention has also been given to the effects 1995), it was shown For example, in the US National Longitudinal Alcohol Epidemiology Survey (Grant, likely to have a than six times more more in the past year were that persons with a major depression cannabis abuse or dependence syndrome. Australian study by Rey, in a recent also emerges This association between cannabis and depression use and mental health (2001) of the association between cannabis Raphael, Patton & Lynskey Sawyer, completed a psychiatric interview while the In the study parents among adolescents. problems a was was that there Among the findings that emerged adolescents completed questionnaires. as well as some other health and depression association between cannabis use particularly strong that cannabis use shows a ‘malignant The authors describe the outcome as indicating problems. is not the issue of causal relationships pattern of co-morbidity’ with other conditions. However, in that survey. addressed Cannabis Use and Depression Cannabis Use and 34 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 1 However, thegeneral ideaofself-medicationasameansreducing distress isplausibleandremains there were nosubstantial difference betweenthegroups thuscontradictingthespecificityhypothesis. to controls, whenangeranddepression were raisedamong allthree groups ofsubstanceabusers, Depression InventoryandtheState-Trait AngerExpression Inventory. Whatemerged isthatcompared and opiates)haddifferent levels ofangeranddepression asdefinedbymeasures in theBeck Nunes (2001)whoexaminedtheextenttowhichthree groups ofsubstanceabusers(cannabis,cocaine of theirpharmacologicalproperties. ThisideawasexaminedinastudybyAharonovich, Nguyen& been suggestedthatparticularpatientsubgroups are likelytobeattractedcertaindrugsbecause distress. Thisissometimesreferred toastheself-medicationhypothesis.Basedonthisidea,ithas One ideathathasbeenputforward isthatdrugabusedrivenbyattemptstoalleviatepsychological brings aboutcannabisusewhichinturnresults inunhappiness). features oftheirlives,althoughitmaywellbethatthere isareciprocal relationship (unhappiness cocaine. Thelinetakenbytheauthorsisthatsubstancemisuse seemsmore ofaresult oftheother less happinessandmore frequent suicidalthoughts.Furthermore, theyusedmore cannabisand of associationwithothernegativefeatures oftheirlivesincludingpoorparent andpeerrelationships, group ofhighschooladolescents whowere clinicallydepressed. Whatwasinteresting wasthepattern depression, particularlyduring adolescence.AstudybyField,Diego&Sanders(2001)identifieda Other studiesindicatethatatleastinsomecircumstances cannabisusecancomeaboutasaresult of factor inastudyofnearly600undergraduates abouthalfofwhomwere frequent cannabisusers. creates avulnerabilitytocannabis useamongusers.Theyclaimtohavefoundevidenceforsucharisk by Simons&Carey (2002)whotaketheviewthatcriticalfactoris‘affect dysregulation’ which r An interesting questionconcernswhycannabisanddepression are associated,assumingthatthe r 18 years.McGeeetal.tooktheviewthatcannabisusewasnotaformofself-medicationbutrather 18 years,buthavingmentalhealthproblems atage15yearsmodestlypredicted cannabisuseatage finding inthisstudyisthatcannabisuseatage15yearsdidnotpredict mentalhealthproblem atage Moffitt (2000)ofabirthcohortbetweenages15and21yearsinDunedin,NewZealand.Animportant Poulton& alcohol andtobaccouse.Thesameimplicationemerges inastudybyMcGee,Williams, depression, thisassociation was notsignificantwhencontrols were appliedforeducational attainment, the USfoundthatwhilethere wasaweakrelationship betweenearlyinitiationtocannabisuseand causal role ofcannabismisuseindepression. AstudybyGreen &Ritter(2000)ofyoungadultmalesin However, studiesthatcontrol forothervariablesandlongitudinalstudiesare lesscertainaboutthe also examinedbutnosubstantialdifferences emerged from thatanalysis. barely outsidethearea ofchance.Femaleversusmalevariation intheextentofassociationwas should benotedhowever, thattheconfidenceintervalissolarge (1.1to2.2)thatthisestimateisonly statistical adjustmentforgender, socialbackground andcigarette smokingwere takenintoaccount.It of suchuse.Relativetonon-users,cannabisusershada1.6timesgreater riskofMDEeven when moderately associatedwiththenumberofoccasionscannabisuseandmore advancedstages American nationalsampleofnearly7,000aged15-45years.Theresults indicatedthatriskof MDEwas cannabis inthedevelopmentofa‘MajorDepressive Episode’(MDE).Datawasgathered from an A recent majorstudybyChen,Wagner &Anthony(2002)examinedthepossiblecausalrole of elationship isnotmediatedbyuncontrolled factors.Onesuggestionismadeinarecent publication eflects a‘willingnesstocontravenethelaw’. The PharmacologicalandToxicological Effects ofCannabis NACD 2004 An Overview of Scientific and other Information on Cannabis 35 neurocognitive The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The Chapter 1 Chapter lkow et al. (1996), extending earlier work, reported lower baseline cerebellar metabolism in chronic lower baseline cerebellar lkow et al. (1996), extending earlier work, reported mains difficult. PET scanning was used to study regional blood flow in cannabis users performing an blood PET scanning was used to study regional mains difficult. Cannabinoids have complex actions on seizure activity and exert both anticonvulsant and activity Cannabinoids have complex actions on seizure In some animal models, marijuana or its constituents can lower the seizure effects. proconvulsant data to determine whether occasional or chronic insufficient currently are there However, threshold. and its some evidence suggests that marijuana Conversely, frequency. cannabis use influences seizure Cannabis Use and Epilepsy Neurocognitive Functioning Neurocognitive in chapter 3). The functioning is considered of cannabis on cognitive (The effects an important consideration when considering the association between cannabis and various forms of when considering the association an important consideration in Chapter 3.) between cannabis use and suicide is considered mental illness. (The relationship changes that may be attributed to chronic cannabis use are subtle and may depend on prolonged and on prolonged subtle and may depend use are cannabis attributed to chronic changes that may be weak evidence of the past two decades have only provided heavy levels of consumption. Studies over data indicate that recent deficits (Rodgers & Robbins, 2002). However persistent neurocognitive heavy use of cannabis may be associated with quite subtle changes in cognitive, and chronic of these changes is not known. Recently, effect particularly attentional, function. The long-term maturation that deficits in human visual scanning (which undergoes et al. (1999) reported Ehrenreich 16 years of by earlier onset of cannabis use (before best predicted between 12–15years of age) are that early use is associated with later cognitive dysfunction. age, versus after 16 years). This suggests may be particularly consistent with the theory that attentional processing also are These results (Solowij, 1998). affected use of cannabis changes associated with chronic Establishing the neural basis for any cognitive re 2000, 2002). After smoking, and after smoking cannabis (O’Leary et al., auditory attention task, before lobes, insula, temporal (orbitofrontal in a number of paralimbic brain regions blood flow increased in temporal lobe regions Blood flow decreased poles) and in the anterior cingulate and cerebellum. a case of a patient with et al. (2001) report Voruganti sensitive to auditory attention effects. function in cannabis during a SPECT study of dopaminergic smoked who surreptitiously schizophrenia binding, indicating increased in striatal D2 receptor was an immediate 20% decrease the brain. There Wilson that early onset of PET findings indicating et al. (2000) reported synaptic dopamine activity. whole brain volume cannabis use (<17years) is associated with structural changes including reduced Block et al. (2000), whereas blood flow; but higher global cerebral matter, of grey and percentage use of marijuana in younger subjects is that frequent imaging, reported using magnetic resonance fluid volume. associated only with lower ventricular cerebrospinal Vo and the basal ganglia areas (orbitofrontal) in prefrontal increases but greater users than in controls, of processing after administration of delta-9-THC. The latter finding suggests that alterations in the may mediate the clinical manifestations of cannabis use involving behavioural circuitry fronto-striatal dysregulation. risks of mental illness, including associated with increased cannabis use is strongly In summary, Use of cannabis, particularly when onset is in younger age psychosis and schizophrenia. depression, defects involving attentional dysfunction and learning. may be associated with neuro-cognitive groups 36 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 1 r from carbonmonoxideinsmoke),athree-fold greater amountoftarinhaled,andretention inthe r which are carcinogens) thantobaccosmoke.Ithasbeenestimatedthatsmokingacannabiscigarette cannabis cigarette containshigherconcentrationsofbenzanthracenesandbenzapyrenes (bothof al., 1999).Inaddition,cannabishasahighercombustiontemperature thantobacco.Thetarfrom a volume, inhalemore deeplyandholdtheirbreath severaltimeslongerthantobaccosmokers(Joyet Cannabis cigarettes usuallydonothavefiltersandcannabissmokersdevelopalarger puff comparable weightissmoked.Thisdifference isprobably theresult ofdifferences inadministration. amount oftarcanbedepositedonthelungscannabissmokers ascigarette smokersifacigarette of tumour promoters andcarcinogens (BritishMedicalAssociation,1997).Asmuchasfourtimesthe as tobaccosmoke,includingcarbonmonoxide,bronchial irritants,tumourinitiators(mutagens), The smokefrom herbalcannabispreparations containsall thesameconstituents(apartfrom nicotine) Respiratory Effects attack of4.8inthehouraftersmokingcannabis. 2001). Mittlemanetal.(2001),inacase-crossover studydesign,calculatedarelative riskforheart cannabis smoking,suggestingthatdelta-9-THCmayhaveeffects onadrenergic systems(Kosioretal., people whowere frequent cannabisusers.Two casesofatrialfibrillationare reported following demonstrate increased cerebrovascular resistance (comparabletonormal60-yearolds)inyoung preparation (Guptaetal.,2001). Herningandcolleagues(2001)usedDopplersonographyto fatality occurred inayoungmanwithrheumaticheartdiseaseafteringestionofbhang,cannabis tetrahydrocannabinol wasfoundinpostmortembloodsamples(Bachs&Moreland, 2001).Another ingestion andsuddencardiovascular death,asintheabsenceofanyothertoxicsubstances, 2000). Arecent caseseriesofyoungadultshasreported an associationbetweencannabis A cerebellar infarct wasreported ina15yearoldmalerelated toheavycannabisuse(Whiteetal., possibility ofothercannabinoidreceptors, asyetunidentified. vascular beds,whichisindependentofCB1orCB2receptors (Kunosetal.,2000).Thissuggeststhe nervous system)locatedCB1cannabinoidreceptors, anandamidecanalsoelicitvasodilationincertain effects ofanandamideandothercannabinoidsare mediated byperipherally-(outsidethecentral effect ofuse.Althoughscientificevidenceindicatesthattheheartrateandbloodpressure lowering pressure andheartratewithchronic use.Conversely, anincrease inheartrateoccursasanimmediate but alsocardiovascular effects insusceptibleindividuals. Theseincludeaprofound decrease inblood Cannabinoids andtheirsyntheticendogenousanaloguesmaycausenotonlyneurobehavioural, Cardiovascular Effects seizures insusceptiblepatients(Gordon &Devinsky, 2001). non-compliance withanti-epilepticmedications.Cannabisuseorwithdrawalcouldpotentiallytrigger seizures. Cannabisusecantransientlyimpairshort-termmemory, andlikealcoholuse,mayincrease active cannabinoidshaveanti-epilepticeffects, butthesemaybespecifictopartialortonic-clonic have beensummarisedinarecent review bytheBritishLungFoundation(2002).Chronic heavyuseof Chronic smokingeffects are similartothoseoftobaccosmoking. Theeffects ofcannabisonthe lungs espiratory tractofone-third more tarthansmokingatobaccocigarette (Ashton,2001). esults inanapproximately five-foldgreater increase incarboxyhaemoglobinconcentration(arising The PharmacologicalandToxicological Effects ofCannabis NACD 2004 An Overview of Scientific and other Information on Cannabis 37 in mutagenic The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The Chapter 1 Chapter eviewed the possible carcinogenic effects mediated by the immunosuppression of delta-9-THC. mediated by the immunosuppression effects eviewed the possible carcinogenic A review of cannabis use and risk of cancer by the World Health Organisation International Agency for Health Organisation of cannabis use and risk of cancer by the World A review the 40 years of age, cannabis increases that in users under on Cancer (IARC, 1990) reported Research particularly of the tongue and larynx, tract, of the upper aerodigestive risk of squamous-cell carcinoma and possibly of the lungs. Other possible tumours linked to cannabis use include non-lymphoblastic was observed for regular carcinogenicity In head and neck cancer, acute leukaemia and astrocytoma. the risk of head than once-a-day for years) cannabis smokers. In addition, cannabis increases (i.e. more duration of use. Interaction has been and manner for frequency and neck cancer in a dose-response smoking and alcohol use. Delta-9-THC seems to have a specific carcinogenic observed with cigarette (2000) Dorrell (Carriot & Sasco, 2000). Furthermore products that of the combustion from different effect r Cannabis and Cancer between cannabis use and certain types of suggested a relationship Several publications have recently to obtain cannabis users, it will be difficult use among regular Given the high rates of tobacco cancer. to cannabis rather than to due among cannabis users are definitive evidence that cancers observed tobacco smoking. it is Animal studies have demonstrated that cannabis smoke may be carcinogenic; It has been calculated that smoking 3-4 cannabis cigarettes a day is associated with the same evidence a day is associated cigarettes It has been calculated that smoking 3-4 cannabis mucosa as 20 or of damage to the bronchial and the same degree bronchitis of acute and chronic on the studies of the long-term effects a day (Ashton, 2001). Prospective cigarettes tobacco more airways disease lacking, but some authors suggest that chronic cannabis smoking are lungs of chronic as with tobacco smoking. a risk may be as great carcinoma and bronchogenic cannabis is associated with increased symptoms of chronic bronchitis such as coughing and wheezing. such bronchitis symptoms of chronic with increased cannabis is associated that is, bullous lung disease in young people, to be associated with reported Cannabis use has been abnormalities in greater are and there et al., 2000). Lung function is impaired watery blisters (Johnson changes Cannabis smoking is associated with of cannabis smokers than non-smokers. airways the large swelling of the airway tissues and redness tissue. Many cannabis smokers have increased in bronchial cannabis for heavy reported et al., 1999). In addition to the risks previously (Roth et al., 1998; Joy regular shown that people who are tobacco (Hall, 1998), studies have recently smokers who also smoke than non-smokers (Hall, bronchitis of chronic symptoms users of cannabis but not tobacco have more et Taylor by reported function were respiratory and decreased symptoms 2001). Significant respiratory of tobacco use, and equating to smokers of 1-10 al. (2000) in young cannabis smokers, independent which adds the risk has been reported fungal spores Contamination of cannabis with per day. cigarettes immune system (Verweij particularly in those with a compromised and systemic infection, of respiratory et al., 2000). laboratory studies of cells (in vitro) and in studies of live animals (in vivo). Cannabinoids impair immune and in studies of laboratory studies of cells (in vitro) to infection, and non-cannabinoids in cannabis smoke resistance decreasing function in rodents, of these (IPCS, 1989). The relevance response involved in local immune impair alveolar macrophages have been very findings to human health is uncertain because the doses of THC used in animal studies immunity in human beings. on high, and tolerance may develop to the effects 38 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 1 pregnancy (Fried&Smith,2001; Fried,2002). birth outcome.FriedandSmithhaveprovided recent reviews oftheeffects ofcannabisusein inconsistent. Thismaybelargely duetothenumerous otherfactorsinutero thatmayalsoinfluence The effects ofsmokingcannabis inpregnancy are unclearasresults ofresearch inthisarea havebeen In aUSCommunitysurvey, 4.1%ofpregnant womentestedpositiveforcannabis (Finchetal.,2001). Effects ofCannabisDuringPregnancy andInfancy low spermcount(Halletal.,1994). and womenintheshortterm(Joyetal.,1999),particularlymales,presence ofapre-existing r Studies havereported areduction infertilitytobeassociatedwithcannabisuse.Onthebasisof Effects onReproduction System (Marselos &Karamanakos1999). especially thosewhoalsosmoketobacco,thattheymaybeatincreased riskofdevelopingcancer cannabis andtobaccosmokeare sufficiently strong towarrantadvisingregular cannabissmokers, It hasbeensuggestedthatwhileawaitingtheresults ofthesestudies,thesimilaritiesbetween cancer risksofcannabisuse. case-control andprospective epidemiologicalstudiesare required toassessmore effectively the ability todetectanincrease in respiratory cancers.Furtherfollow-upofthiscohortandadditional prevalence ofregular cannabisuseamongparticipantsin this cohortstudymayhavereduced its prostate cancer, afindingthatneedstobefurtherexamined.Therelative youthandthelow r cancer. Theonlyprospective studytodatedidnotfindanincreased incidenceofheadandneckor one case-control studyhasfoundanassociationbetweencannabissmokingandheadneck gastrointestinal tractcancersamongrelatively youngadults whohavebeendailycannabisusersand The epidemiologicalevidenceisconflicting.There are case reports ofupperrespiratory and evidence onthecancerrisksofcannabisuseisstilltooweaktowarrantstrong conclusions. As outlinedinarecent review byHallandMacPhee(2002), experimentalandepidemiological Solowij, 1998). considered intheanalysisofdatafrom thesestudiesandthisarea requires furtherstudy(Halland r Some casestudieshavefoundanincreased riskofchildcancersinchildren borntomotherswho found noevidencethatcannabis causesbirthdefects(congenitalanomalies)(Zuckermanetal., 1989). for adolescentmothers(Cornelius etal.,1995).Large well-controlled epidemiologicalstudies have been smallcompared totobacco(Fried,1998).There islittleevidencethatgestation shorter except 1998; Joyetal.,1999).Theeffects ofcannabissmoking,where thestudyhasfoundanassociation, has variables butthislinkhasnotbeen foundinotherstudies(Zuckermanetal.,1989;HallandSolowij, controlled studyhasfound this relationship hasremained aftercontrolling foranyconfounding Some studieshavesuggestedthatcannabissmokinginpregnancy mayreduce birthweight.A Birth Weight andCongenitalAnomalies esearch onanimalsithasbeenargued thatcannabiswould probably decrease fertilityforbothmen espiratory cancers(Sidneyetal.,1997).Thisstudydidfind,unexpectedly, anincreased rateof eported usingcannabisduringtheirpregnancies. Howevercannabiswasoneamongstseveralfactors The PharmacologicalandToxicological Effects ofCannabis NACD 2004 An Overview of Scientific and other Information on Cannabis 39 (DSM-IV; American Psychiatric Association, (DSM-IV; The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The Chapter 1 Chapter Diagnostic and Statistical Manual of Mental Disorders esults. To date there is insufficient evidence to support an association between reduced birth weight, birth evidence to support an association between reduced is insufficient date there esults. To Dependence Potential in Humans The 1994) presents criteria for the diagnosis of psychoactive substance dependence, based largely on the substance dependence, based largely criteria for the diagnosis of psychoactive 1994) presents of DSM-IV substance dependence are The key features concept of the dependence syndrome. to use the cognitive, behavioural and physiological symptoms, indicating that the individual continues The criteria include tolerance, a withdrawal problems. substance despite significant substance-related in consumption and a pattern of use which leads to a reduction in controlling difficulty syndrome, et al. (1994) found the DSM concept of Morgenstern other important activities. In an empirical study, stimulants and cannabis dependence at least as valid as those for dependence on alcohol, opiates, sedatives. (CIDI), and A DSM diagnosis is made on the basis of the Composite International Diagnostic Interview accreditation it is a lengthy instrument requiring and validity, while this instrument has good reliability Sudden Infant Death Syndrome use could be a weak risk factor for Sudden Infant Scragg et al. (2001) suggested maternal cannabis by Klonoff- for maternal smoking. This is in contrast to reports even after controlling Death Syndrome, use at conception and in the postnatal period, but not Cohen and Lam-Kruglick (2001) that paternal the risk of Sudden Infant Death Syndrome. to increase maternal use, was reported cannabis on the developing foetus have yielded conflicting of of the effects reports In summary, r to distinguish the influence difficult It remains congenital anomalies, or sudden infant death syndrome. that might be the influences factors such as nutrition and socioeconomic status from of concurrent on behavioural development suggest a attributable to cannabis use. Recent studies of the effect possible link, but this would need further study. Behavioural and Developmental Effects Behavioural and during the first in utero on infants exposed effects Cannabis may have behavioural and developmental been exposed to cannabis in who have of 4 and 9 children few months after birth. Between the ages the shown deficits in sustained attention, memory and cognitive functioning. However, have utero The underlying causes to tobacco and their clinical significance is unclear. small compared were effects underlying the to the reasons closely related or might be more might be the cannabis exposure 1998; Joy et al., 1999; Fried (Fried, 1998; Hall and Solowij, mothers’ use of cannabis during pregnancy and Smith, 2001). in from of executive function resulting IQ, a negative effect is no evidence for reduced Although there between relationship study showed a prospective (Fried, 2002). A been reported has exposure utero inattention) in 10 year impulsivity, (hyperactivity, and various behavioural problems exposure prenatal (Goldschmidt et al., 2000). old children Data on cannabis use was collected during the Avon Longitudinal Study of Pregnancy and Childhood of Pregnancy Longitudinal Study was collected during the Avon Data on cannabis use was no There or during pregnancy. before et al., 2002). 5% of mothers smoked cannabis (Fergusson to be reported but birth weight was care, risk of perinatal death or the need for special increased lower. 40 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 1 that cannabinoid receptors maycontribute tothesusceptibilitydrugabuse. authors concludedthatindependent studiesshouldbedesignedtofurtherconfirmthehypothesis of cannabinoidreceptors inthemodulationofdopamineand cannabinoidreward pathways.The greatest forcocaine,amphetamine,andcannabisdependence. Theresults are consistentwitharole genotype thanforothergenotypes. Theassociationwithspecifictypesofdrugdependence was number ofintravenousdrugsusedwassignificantlygreater forthosecarryingthe>or=/>=5 with amodelwhere homozygosity forthe>or=5repeat allelesshowedthegreatest effect. The dependence variables.ByANOVA onlyfactor1showedsignificantdifferences bygenotypeconsistent to factoranalysis,1showedaclusteringofdrugdependence variablesandfactor2ofalcohol and three genotypes<5/<5, heterozygotes, and>or=/>=5.Whenallvariableswere subjected the 4thallele,and<4alleleswere rare, thealleleswere dividedintotwogroups, <5andor=5, distribution ofallelesincontrols versusintravenousdrugusersshowedadecrease inthefrequency of of substanceabusesymptomsusingtheAddictionSeverityIndex (ASI).Sinceinspectionofthe all typesofsubstancedependenceusingtheDiagnosticInterview Schedule(DIS),andforavariety Unit (ATU) and114 controls. Allwere non-HispanicCaucasians.TheATU subjectswere screened for examined byComingsetal.in1997.Thestudyconsistedof92subjectsonanAddictionTreatment variants oftheCNR1genemightbeassociatedwithsusceptibilitytoalcoholordrugdependencewas 9 alleles.Sincethecannabinoidsystemispartofreward pathwaythehypothesisthatgenetic A microsatellite polymorphism(AAT) atthecannabinoidCB1(brain)receptor gene(CNR1)consistsof The GeneticsofSusceptibilitytoDependence activate thesamebrainwithdrawalprocesses asactivatedbywithdrawalfrom otheraddictivedrugs. processes insimilarfashionto otheraddictivedrugs.Inaddition,cannabinoidwithdrawalappearsto biochemical evidence,Gardner (2002)reported thatcannabinoids appeartoenhancebrainreward dependence (2001).Onthebasisofareview ofmore than 15yearsofelectrophysiological and In arecent review, Johnsreported thatoneintenpeoplewhohaveusedcannabisare atriskof dependence. The authorsconcludedthatprogression beyondweeklyuseofcannabiscarriesasignificantrisk frequently thandependentalcohol users,withdrawalsimilarlyandtoleranceconsiderablylessoften. r consequences 18%.Thecombinationofwithdrawal,persistentdesire andunintentionalusewas obtaining/using 74%;continuedusedespitehealthproblems 63%;tolerance21%;andsocial cannabis userswas:persistentdesire 91%;unintentionaluse84%;withdrawal74%;excessive time (11% males,4%females)metcriteriaforcannabisdependence.Symptomprevalence independent at al.(2002)reported that59%reported lifetimeuseofcannabis,17%usedatleastweeklyand7% 1601 youngadults(meanage20.7years)from anAustralianlongitudinalcohortstudy(N=2,032) Coffey become dependentwhileafurther41haddevelopedsymptomswithoutdependence.Instudyof examined cannabisdependenceinacommunitysampleandfoundthatof599users,37had of Australiancannabisusersmetcriteriafordependence.Rosenberg &Anthony(2001) Three recent studiesare worthyofattention.AstudybySwiftetal.(2001)foundthatalmostone-third dependence. have goodpsycho-metricproperties andwhichwouldallowformore widespread studyofcannabis to administer. Swift,Copeland&Hall(1997)describethree shorterinstrumentswhichwere shownto eported by57%.Dependentcannabisusersreported compulsiveandout-of-control usemore The PharmacologicalandToxicological Effects ofCannabis NACD 2004 An Overview of Scientific and other Information on Cannabis 41 The Pharmacological and Toxicological Effects of Cannabis Effects and Toxicological Pharmacological The Chapter 1 Chapter There is a need to monitor the potency of cannabis available on the Irish market; is a need to monitor the potency of cannabis There of cannabis use among people with mental is a need to establish the extent and significance There in Ireland; health problems illnesses. of cannabis use among people with respiratory is a need to study the extent There olerance ■ ■ ■ Gaps in Knowledge on the pharmacology and toxicology of cannabis continuing and the Obviously the research the beginnings of answers to some of the questions raised in is likely to provide international literature to give consideration to the following important is a need In the Irish context, there this chapter. matters: Conclusions dependence in the DSM-IV include tolerance, a withdrawal As noted above, the criteria for cannabis have area in this of the literature consumption. Some reviews in controlling and difficulty syndrome, (Johns, has now been unequivocally demonstrated concluded that the cannabis-withdrawal syndrome symptoms (2002), on withdrawal the literature of review recent 2001). In contrast Smith, in a more on which to draw any enough evidence date do not provide suggested that the studies conducted to from in human users. It is evident withdrawal syndrome conclusions as to the existence of a cannabis be at risk of of users who may percentage is little on the that there here the studies reviewed becoming dependent. as clear a withdrawal pattern as cannabis cannot be said to provide research On the basis of current the slow other drugs of abuse, such as opiates. This is to be expected of the long half-life and elimination of metabolites. T and systems as alcohol, cocaine, the same reward may affect Animal studies suggest that cannabinoids effects, tolerance to its subjective and cardiovascular opioids. Heavy smokers of cannabis also develop on the abrupt cessation of cannabis use (Hall & Solowij, 1998). withdrawal symptoms and some report Striking individual differences in responsiveness to cannabinoids have been observed that might to cannabinoids have been observed that in responsiveness Striking individual differences In a preliminary receptor. cannabinoid the gene encoding the brain-expressed involve mutations in was comparatively coding region (2000), the human CB1 cannabinoid receptor study by Hoehe et al. acute psychotic symptoms after showed group of individuals: one groups sequenced in different after longterm heavy did not develop any psychopathology another group cannabis intake, while insight some which might provide for structural mutations was obtained, cannabis abuse. No evidence to cannabinoids. responsiveness of individually-different into the molecular basis 42 An Overview of Scientific and other Information on Cannabis NACD 2004 158(12): 2033-7. 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Knowledge, perceptions and availability of information; Knowledge, perceptions and patterns of use; Prevalence Characteristics and behaviour of users; Indicators of health consequences; The availability and quality of product on the market; of product The availability and quality vailability and Quality of Product on the Market of Product vailability and Quality vailability at Consumer Level (Extent/Quantities) vailability at Consumer Level espectively. The figure for the United States (78%) is well above the European average. for the United States (78%) is well above the European The figure espectively. Sources for users, namely adolescents, was a frequently overlooked area of research until the ESPAD of research overlooked area was a frequently for users, namely adolescents, Sources they could buy cannabis. students know a place where 50% of European Report (1999). Approximately by park etc.” being mentioned by 40% and “school” rises to 78% with “street, this figure In Ireland, to the question 23%. Brinkley et al. (1999) examined the same variables and found similar results Sources at Consumer Level Sources A an to evaluate from unknown and difficult is largely The availability of cannabis at consumer level by consumers of on self-reports rely epidemiological standpoint. Most studies ■ ■ A for as a primary reason is warranted because availability is often cited Further analysis of this area using the drug (Brinkley et al., 1999). study on the experience of drug use among secondary school Brinkley et al. (1999) conducted a large obtain a “joint”, students in Dublin. Seventy-one per cent of students in this sample said they could 25% answering that they easily obtain cannabis and approximately that they could with 45% reporting definitely could not find cannabis. In find the drug. Less than 10% said they could probably Fifty-four per cent of cannabis was most easily accessible. comparison to all illicit drugs in this study, the drug on at least one occasion. offered that they were students reported 15- Report targetting on Alcohol and Other Drugs (ESPAD) Project Schools Survey The 1999 European easy Union noted similar findings concerning the relatively the European 16-year olds in schools across as “very” or “fairly easy” to the drug per cent of the sample reported access to cannabis. Twenty-eight above the easy attainment was well who reported olds in Ireland of 15-16-year obtain. The percentage countries (59%). Denmark and the United Kingdom followed Ireland, average for other ESPAD r ■ ■ ■ ■ This chapter addresses the public health risks related to cannabis use including a review of the of a review to cannabis use including health risks related the public This chapter addresses material in the chapter is presented of health outcomes of cannabis use. The epidemiological studies as follows: under seven main headings ■ Public Health Risks of Cannabis Use: Risks of Cannabis Health Public Evidence Epidemiological Overview Chapter Two Chapter 52 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 2 containing cannabisvariedsubstantially, butonaverage,cigarettes madefrom cannabisresin cause andeffect. AnanalysisinIreland from 1980to1996 foundthattheweightofcigarettes 9-THC. Ifthedrugwere consumedorally, itwould takesubstantiallymore than thisamounttoproduce lowest There islittledataonaveragedosesandconcentrationlevels inIreland andtherest ofEurope. The 1 ofthisreport.) (Further chemicalandpharmaceuticaldetailonthedifferent typesofcannabisiscontainedinChapter biscuits (Corrigan,1994). cigarettes (‘joints’)butcanalsobesmokedinpipes,madeintoadrinkorcookedcakes or by dippingintobaccoandthensmoking.InIreland, cannabisisusuallysmokedinhome-made cannabis plant.Cannabisoilisprepared byextractionandsubsequentdistillationisconsumed most popularinIreland andmost ofEurope. Itcomesintheformofasolidblockscrapedfrom the United States,istakenfrom the driedleavesandflowers.Cannabisresin, alsoknownashashish,is the topsofuncultivatedplants.Herbalcannabis(ghanga,marijuana),mostwidelyusedformin There are fournotedtypesofcannabis.“Bhang”whichis the leastpotentoftypes,comesfrom A (59%), Denmark(57%),theUnitedKingdom(52%),CzechRepublic(50%)andSlovenia(47%). 1999. Thetopfivecountriesin1999where cannabiswasperceived tobeeasilyobtainedwere Ireland perceive cannabisas“veryeasy”or“fairlytoobtainhasincreased intheperiodfrom 1995to cannabis. TheESPAD Report(1999)foundthatinmostcountries,theproportion ofstudentswho Another methodemployedtodetermineavailabilitytrends issurveyingthoseadolescentswhobuy number alonemanyalsoreflect Garda andCustomactivity. in 2001.However, boththenumberandquantity ofseizures are importanttoidentifytrends, asthe offences forpossessionofcannabishasincreased steadily from 4,186in1999to4,88020005,083 the AnnualReportsofGarda Síochánarecords (e.g.AnGarda Síochána,2004).Thetotalnumberof for thecountryinwhichtheyare seized(Sinclairetal.,2001).Dataondrugseizures are availablefrom may reflect lawenforcement policies,ratherthanactualavailability, orthedrugsmaynotbeintended and theotherisbasedonself-reports ofthosewhobuydrugs.Figures forcannabispossession neither iscompletelyreliable. Oneisthrough dataforoffences forcannabispossession andsupply Drug availabilitytrends are difficult tomeasure. There are twomainindicatorsofavailabilitytrends and Tr (See chapter4forinformationontheretail marketrelevant tocannabis.) ever havingpurchased it. said theyboughtitfrom astranger. Interestingly, ofthosewhohaveusedcannabis,only38%report addition, 15%saidtheyreceived thedrugfrom asibling,6%saidtheystoleitfrom home,and25% 62% ofpupilswhohadreported useofcannabissaidthatitwasshared around agroup offriends.In much higherpercentage inthepreviously mentionedstudy. Whenaskedhowtheyobtainedcannabis, disco” and“atfriend’s home”.Only6%saidtheywere offered cannabisatschoolcompared witha “where wasthedrugoffered”. Themostcommonplacewas“onthestreet” followedby“ataraveor verage DoseandDegree ofVariability ends inAvailability dose producing behaviouralresponses whencannabisissmokedtwomilligrammesof delta- Public HealthRisksofCannabisUse:EpidemiologicalEvidence NACD 2004 An Overview of Scientific and other Information on Cannabis 53 Public Health Risks of Cannabis Use: Epidemiological Evidence Use: Epidemiological Cannabis of Risks Health Public Chapter 2 Chapter esearch indicates that the THC content of marijuana, or herbal cannabis, is on the rise – El Sohly et al. that the THC content of marijuana, or herbal cannabis, is on the rise – El Sohly indicates esearch Report, 4% to 5% for many years in the UK (House of Lords fairly stable at around esin has remained changes in false and compares 10-20 fold are increased eports suggesting that concentrations have was identified. in this area esearch Purity Levels and Presence of Adulterants Presence Purity Levels and The international (THC) content. is based on its tetrahydrocannabinol The potency of cannabis r 1.5% in 1980 to 4.2% in 1987. Cannabis from that potencies of confiscated samples rose (2002) report r stable between 2% and 4%. relatively have also remained 2000). In New Zealand, THC concentrations His available in Ireland. (2001) has examined the THC content of cannabis In the Irish context Maguire market in being traded on the black of cannabis herb are conclusion is that ‘…high potency varieties THC findings was the variation in about Maguire’s (p. 231). What was especially interesting Ireland’ He found that while the average large. in dose is very content, with the implication that the difference 0.4 to 8.2 mg. using herbal cannabis was 4.3 mg, it could range from THC content in a joint prepared with a value of 16.2 mg THC in a joint containing cannabis resin. This compares on the has also shown that concentrations vary considerably depending The international literature (Niesink, 2000). El Sohly (2002) points out that of administration and the route its source product, r 1985; 4.72% in 2001) and marijuana (2.84% in average concentrations of THC of commercial-grade in 2001). Hall and Swift (1999) point out that usage high-grade sinsemilla (7.17% in 1985; 9.03% potent types is the most significant use of more regular practices among heavier users and their more factor in changes consumption. than 400 chemical compounds. In addition, As noted in Chapter 1, cannabis contains more and as microbes adulterants, including pesticides, as well as naturally occurring contaminants such patients such as these could pose a risk to immuno-suppressed and fungi, may also be present, it was observed that the overall Report, 2000). In the same report people with AIDS (House of Lords years; “many users perceive to have fallen in recent appeared quality of imported cannabis resin with the confirms that this is the case, analysis frequently forensic as adulterated and cannabis resin one of the addition of caryophyllene, a constituent of cloves, being particularly common”. However, and that case experts contended that the concern about herbicide contamination was unfounded, contamination was limited. A need for more microbial from history evidence of health problems r as the clearest One early study identified contamination of marijuana by spraying with defoliants of concerns about the possible health effects are significant 1986). More danger to health (Hollister, illicit used to control the use of cannabis contaminated by herbicides (such as paraquat) that were have also been concerns about the cannabis cultivation in the US in the 1970s (WHO, 1995). There has been little evidence (other than a small number contamination of cannabis leaf but there microbial 1986). the health of cannabis users (Hollister, of case histories) that this has adversely affected contained 102 milligrammes of resin and cigarettes made from herbal cannabis contained 260 herbal cannabis contained made from and cigarettes of resin contained 102 milligrammes of amounts used in is no indication (Buchanan & O’Connell, 1998). There milligrammes on average pipes or ‘bongs’. 54 An Overview of Scientific and other Information on Cannabis NACD 2004 (O’Brien &Moran,1998). averages. InDublin,street pricesvarygreatly according todemandandvariousareas ofthecityitself cannabis leavespergramwasconsistentlyreported at Chapter 2 many users)? cannabis consumptionthatisacceptablefordriving? isthethreshold of progression tootherdrugs;inwords, isthegatewayhypothesisvalid?What notes thefollowingquestionsregarding cannabis:Whyiscannabisuseassociatedwiththe Spruit (2002)summarisingthefindingsofanInternationalScientificConference onCannabis(2002) acceptance ofthedrugwillexacerbateproblem, aswasseenwithtobacco. innocuous, theyexpress concern aboutincreasing prevalence ratesamongyoungpeople. Societal Although chronic cannabisuse isanexperienceofasmallminorityandconsequencesuseappear Hall &Babor(2000)callforheightenedattentionintheneglectedarea ofcannabisaddictionresearch. (NACD &DAIRU,2003). Drug andAlcoholInformationResearch UnitofNorthernIreland hasrecently been published general populationinIreland, commissionedbytheNationalAdvisoryCommitteeonDrugs,and collected someinformationondrugusage(Kelleheretal.,2003).Asurveyofamongthe population studies–SurveyofLifestyle,AttitudesandNutrition(SLÁN)in19982002which for HealthPromotion Studies, NationalUniversityofIreland (NUI)inGalwayhaveconductedtwo There isadearthofgeneral population surveysonprevalence ratesconductedinIreland. TheCentre A of Information Knowledge, Perceptions andAvailability (per gram)hasremained steadyat Ireland (reported byMoranetal.,2001).Theindicationsare thattheaveragepriceofcannabisresin The Garda NationalDrugsUnitprovides mostofwhatisknownaboutstreet pricesofcannabisin T which tobaccowas eventuallyfoundtocauselung cancer. Although evidenceofpulmonaryeffects is will soonbecausallylinkedtolung cancer. Theycompare thedelayofthisdiscoverytoonein more harmfulconsequencesthanmostbelieve.Theauthors writethatitislikelysmokingcannabis The HouseofLords ReportonCannabis(2000)contendsthat consumingthedrugbysmokinghas concept of‘pack-years’forcigarettes and‘units’foralcohol. tolerance. Thishighlightstheneedforanacceptedmeasure ofexposure tocannabissimilarthe dosage willaffect auserduetofactorssuchasvariabilityinindividualsmokeinhalation(chapter 1)and (International ScientificConference onCannabis,2002).Itisdifficult todeterminehowoneparticular wave ofuseinthe1960sand1970s,effects onone’s healthasaresult are largely unknown Although theproportion ofTHCincannabispreparations hasincreased significantlysincethefirst A ypical PricesandRange vailability ofScientificInformationonProduct vailability ofInformationonEffects ofProduct Public HealthRisksofCannabisUse:EpidemiologicalEvidence € 13 fortheyears1995through 1999.Likewise,theaveragepriceof Who € 3 forthesameperiod.Thesefigures are only uses and why (as opposedtosimply, how NACD 2004 An Overview of Scientific and other Information on Cannabis 55 Public Health Risks of Cannabis Use: Epidemiological Evidence Use: Epidemiological Cannabis of Risks Health Public Chapter 2 Chapter General Population the occasional use adolescents aged 15-16 perceived Report (1999) found that European The ESPAD use. Between 21% and 24% of students in Denmark, of cannabis to be less injurious than regular risk. A much higher France, and the United Kingdom believed occasional cannabis use to be a great it to be a very risky and Portugal perceived of students in Romania, FYROM, Lithuania, percentage Level of Knowledge of Product, Effects and Perceptions among and Perceptions Effects Level of Knowledge of Product, Consumers of Product (Brinkley et al., 1999). of cannabis as the effects and pleasure relaxation Irish students typically report as well as enhancement and pleasure name relaxation Cities” study in the “Three participants Similarly, of pupils in the for cannabis use (Cohen et al., 2001). A higher proportion of activities as reasons to any other illicit drug. Those that of cannabis compared Brinkley et al. study could cite the effects and cocaine and to heroin of other illicit drugs typically attributed negative effects knew the effects favourable light and cannabis and in the most Alcohol was perceived to ecstasy. neutral effects to cannabis and close behind. Fifty-nine per cent of students attributed positive effects tobacco were that reported A small percentage mainly negative effects. cannabis as producing only 11% perceived any effects. cannabis did not produce & Babor (2000) note Much debate has been given to the issues of the ‘normalisation’ of cannabis. Hall it to a legal drug, tobacco. With acceptance, equating its social tolerance and widespread high Von a part of growing-up. may just be considered rates especially in youth populations, it prevalence and New Zealand, cannabis Sydow suggests that for adolescents in the USA, UK, Germany, is no strong experimentation is a “normative life-event” (p49). Wibberlythat there & Price (1998) report However, evidence indicating that the use of cannabis has become normalised among adolescents. indicates that cannabis and cocaine are of adult friends in London one study among a group only further aspect of daily life” (Pearson, 2001, p1). However, “accepted as a normal and routine so, in what groups. investigation into the issue can ascertain whether normalisation truly exists, and if of risk, participants in a longitudinal study in New and legal perceptions to the social In regards attitude about cannabis use and held a laissez-faire from resulting Zealand saw few social problems given the legal consequences (Poulton et al., 2001). These feelings may not generalise to Europe rates in New Zealand. much higher prevalence When Irish 16-year olds were asked their reasons for first illicit drug use, the number one reason was for first illicit drug use, the number one reason asked their reasons When Irish 16-year olds were to “get high” as the second most important reason per cent named the desire Twenty-two curiosity. reasons and related to peer pressure referred proportion for experimenting with drugs. A much lesser – 80% of students said 1999). Brinkley et al. (1999) found similar results for first illicit drug use (ESPAD, “I like “they wanted to try” and 44% gave the reason they took illicit drugs for the first time because the effects”. Level of Awareness of Product Amongst Drug Consumers in General Amongst Drug Consumers of Product Level of Awareness beginning to emerge, the epidemiological evidence in relation to cancer is conflicting. However, to cancer is conflicting. evidence in relation the epidemiological beginning to emerge, (Hall & review of cancer has been suggested by a recent risk users of an increased advising regular is contained in of cannabis use discussion of the health effects detailed MacPhee, 2002). A more Chapter 1. 56 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 2 . Themajorityofthepublicare aware ofthemanyillicitdrugsinexistence.However, they failto 1. perception ofdrugsingeneral,whichcanbeappliedtocannabisparticular: of thegeneralpopulationinIreland. Theauthorsgeneratedfourconclusionsregarding thepublic’s Research Division(Bryanetal., 2000)havepublishedareport ondrug-related knowledge andattitudes people todrugs,there islimited availabilityofinformationrelating toallagegroups. TheDrugMisuse While anumberofstudieshaveassessedboththeusagepatternsandattitudesstudentsyoung negatively thantheirmalecounterparts(reported byDrugPrevention.net, 1997). the accompanyingfeelingsofdifferent drugs.Typically femalestudentsperceive drugs more had difficulties differentiating betweentheeffects ofvariousdrugs,youngpeoplefailedtodistinguish cannabis were expressed bothbythoseinthe10-13and 14-17-yearoldcategories.Justasadults awareness andabilitytoidentify different drugsincreased withage.Highlevelsofawareness of Cannabis wasratedastheleastharmfulillicitdrugby14-17-yearoldsinNorthernIreland. Drug frequently, inlarger quantities,andbeganatanearlieragewhencompared withgirls. demonstrated (butsmall)differences ingenderare takenintoaccount.Boysuseddrugsmore schools. Thishigherpercentage inboys’dissatisfactionwithdrugknowledgeisinteresting whenthe Moreover, 73%ofboysand57%girlsexpressed dissatisfactionwithdruginformationintheir Over aquarterofyoungpeopleinDublindidnotknowtheeffects ofcannabis(Brinkleyetal.,1999). DrugPrevention.net). having adequateknowledgeontheeffects andrisksofdrugsingeneral(reported by Behaviour andAttitudesSurveycarriedoutinNorthernIreland, nearlyone-third ofstudentsreported negative effects ofcannabis compared to14%ofnon-users.According tothe2002Young Persons’ were more likelytocitepositiveeffects ofthedrugthannon-users.Likewise,only5%userscited liking theeffects wasareason for40%ofthestudents.Brinkleyetal.(1999)foundthatcannabisusers r the negativeeffects theyknowtobetrue(Brinkleyetal.,1999).Seventy-ninepercentofstudents that feel theeffects asreasons forfirstuse,whilethemajority ofnon-usersdonottakedrugsbecause Interestingly, youthswhousecannabisandotherdrugsmostcommonlycitecuriositywantingto of use. behaviour. Countrieswithlowerratesofriskyperceptions hadcorrespondingly higherprevalence rates great risk.Ireland hadoneofthelowestfigures, withonly63%perceiving regular cannabisuseasrisky 94% ofstudentsinsomecountries,suchasRomania,Cyprus,andSweden,considered regular usea behaviour. Regularuseofcannabiswasperceived ascarryingamuchgreater risk.Asmanyas88%to . Overhalf(53.1%) ofthepopulationbelievedrugexperimentationtobe typicalinadolescence.In 3. Attitudestowards illicitdrugsare mostlynegative.Over97%ofIrishpeoplehadheard ofcannabis, 2. efuse drugsdidsobecauseitisbadforhealth,56%gave“riskofdependency”asareason, andnot make distinctionsbetweenthedifferent effects ofdifferent drugs; 2001). Lessthan halfagreed thattheoccasional useofcannabiswasnothazardous tohealthand pertaining todruguse,figures ofstudentsusingcannabisranged from 12%to37%(Moran etal., the caseofcannabis,thisunease maybeslightlyexaggerated.Inareview onyouthstudies and prevention ismostfocused; as adeterrent touse,thisbeliefisembracedmore byadults thanyouth,where drugeducation yet nearly80%believedalldrugstoproduce equallyharmfulhealtheffects. Althoughthismayact Public HealthRisksofCannabisUse:EpidemiologicalEvidence NACD 2004 An Overview of Scientific and other Information on Cannabis 57 55-64 45-54 35-44 Public Health Risks of Cannabis Use: Epidemiological Evidence Use: Epidemiological Cannabis of Risks Health Public 25-34 Chapter 2 Chapter Figure 2.1: Recent Cannabis Use Figure 18-24 5 0 30 25 20 15 10 The Surveys of Lifestyle, Attitudes and Nutrition (SLÁN) in 1998 and 2002 by the The Surveys of Lifestyle, Attitudes and Nutrition Source: SLÁN Survey 1998 reported by Moran et al., 2000 SLÁN Survey 1998 reported Source: espondents were in favour of drug prevention and rehabilitation programmes. and rehabilitation in favour of drug prevention espondents were 54.7% believed regular cannabis use is as harmful as that of heroin. Overall, drug use among Overall, drug that of heroin. cannabis use is as harmful as 54.7% believed regular However, respondents. was of grave concern to the study’s in general young people in Ireland concern than drug abuse; country warranted more alcohol abuse in this social addicts and blame the person, not the of fear and apathy towards general. They cite feelings the drug users, most of towards negative attitudes Despite the public’s context for the addiction. r espondents in 2002 and 11% in 1998 reported using cannabis in the past twelve months. A clear espondents in 2002 and 11% in 1998 reported 4. those who use drugs in attitudes towards concluded that the Irish hold fairly intolerant The authors Prevalence and Patterns of Use Prevalence Extent of Use of Product (Moran et al., 2001; ESPAD, and elsewhere drug in Ireland Cannabis is the most commonly used illicit used drug, after alcohol most widely 2003) and the third 1999; Brinkley et al., 1999; NACD & DAIRU, the popularity of cannabis (O’Brien et al., confirm Ireland and tobacco. Studies conducted throughout Cork, Kilkenny, Kildare/Wicklow, region, Heath Board 2000). Selected studies in Dublin, the Midland cannabis to be the most common illicit Region found and the North Eastern Health Board Longford, included solvents). region drug (North Eastern Health Board General population: Centre for Health Promotion Studies, National University of Ireland (NUI) in Galway are the most (NUI) in Galway are Studies, National University of Ireland for Health Promotion Centre general population to date. Only of cannabis use in Ireland’s studies on the prevalence comprehensive 2003), available at the time of writing (Kelleher et al., of the 2002 study were results the preliminary by Moran et al. (2000). The study’s reported concentrate on the 1998 results here hence the results Overall 9% of for those 18-years-of-age and older. registers electoral sample was selected from r cannabis usage in gender balance was evident with 12% of men and 7% of women in 2002 reporting use) in 1998). In 1998, the last 12 months (recent the past twelve months (11% and 6% respectively (10.9%), 18-24 years (26%), 25-34 years were by age groups rates for cannabis consumption prevalence 35-44 years (3.2%), 45-54 years (1.7%), and 55-64 years (0.5%). Bryan et al. (2000) also reported that 66% of the general population in Ireland agreed that cannabis agreed that 66% of the general population in Ireland Bryan et al. (2000) also reported legislation favour of changing the current not be in therefore use should be against the law and would which criminalises the possession of cannabis. 58 An Overview of Scientific and other Information on Cannabis NACD 2004 years-of-age). Thehighpercentages foundintheESPAD ReportforIreland were notseenelsewhere 12% and32%(eachstudyused aslightlydifferent agegroup, buttherangewasbetween9and18- A review onyouthdrugsurveys(bothlocalandnational)reveals lifetimeprevalence ratesvarybetween marijuana/hashish inIreland (32%)isdoubletheaveragefor allESPAD countries(16%). compared totherest ofEurope. Datafrom thissurvey showsthatthepercentage ofthosewhouse Italy, andSlovenia.Cyprus,Romania,Sweden,theFaroe Islandshadverylow rateswhen countries withrelatively highprevalence ratesincludetheUnitedKingdom,France,CzechRepublic, cannabis consumptioninallthree categories–lifetime,last12months,and30days.Other decreased since1995(significantlyforboysonly),Ireland stillranksamongthetopcountriesfor lower thanthatforlifetime,presumably duetotheyoungagecohort).Althoughthesefigures have 30 dayswas15%andinthelast12months26%(themeasures ofcurrent useare onlyslightly among adolescentsinIreland was32%in1999(boys35%andgirls29%).UsebyIrishyouththelast Ireland rankedasoneofthetopcountriesforcannabisuse.Lifetimeprevalence forcannabisuse examining prevalence ratesand related informationfor15-16-yearoldsin30European countries. School andyouthpopulation: age-group haddoneso. has usedcannabisatsometimeintheagegroup 15-34years,whileonly3.5%ofthoseinthe55-64 expected theprevalence of use wasmuchhigheramongyoungpeople.Around oneinfourpeople just onepercent lessinNorthernIreland hadusedcannabis atsometimeintheirlives.Asmightbe feature wasthatcannabisthemostwidelyusedillegaldrug.Just18%ofpeopleinsouthand the latterpartof2002andinearly2003.From theviewpointofpresent work,themostinteresting published (NACD&DAIRU,2003).Nearly9,000peoplewere surveyedinface-to-faceinterviewsduring More recently, thepreliminary results ofanationalsurvey(Ireland, northandsouth)hasbeen Chapter 2 (13%), 40-50years(9%),51-65(2.2%),66+(1.4%)(Bryanetal.,2000). sample agedover18years.Percentages ofusebyagerangeswere 18-29years(29.5%),30-39 attitudes andbeliefsoncannabis,lifetimeuseofcannabiswasreported by12.4%ofthepopulation rates for18-34-yearoldsreached 30%,whileratesforalladultswasnearly20%.Inastudyon Irish users, butonly9.4%ofalladultsaged18-64are current cannabis users.Similarly, lifetimeprevalence is clearlyconcentratedamongtheyoungerpopulations;17.7%of18-34-yearoldsare current cannabis having usedcannabisatleastoncecompared to2.1%ofthe55-64agegroup. Cannabisconsumption Lifetime cannabisusereflects thesameinverserelationship withage,33.4%ofadultsaged18-24 Public HealthRisksofCannabisUse:EpidemiologicalEvidence Source: IrishSocialOmnibusSurvey1998reported by Bryanetal.,2000 10 15 20 25 30 35 0 5 18-29 ESPAD (1999)publishedoneofthelargest youthpopulationstudies Figure 2.2:LifetimeUseofCannabis 30-39 40-50 51-65 66+ NACD 2004 An Overview of Scientific and other Information on Cannabis 59 Public Health Risks of Cannabis Use: Epidemiological Evidence Use: Epidemiological Cannabis of Risks Health Public Chapter 2 Chapter efers to any aspect of the drug taking process, while misuse “…refers to the use of while misuse “…refers efers to any aspect of the drug taking process, r Use wo points are worth mentioning. The first has to with the difference between the ESPAD estimate for between the ESPAD worth mentioning. The first has to with the difference wo points are eported lifetime use of cannabis, but almost 90% of those lifetime users had tried it only a few times eported lifetime use of cannabis, but almost 90% of those lifetime users had tried it only (See chapter 1 for further discussion of cannabis dependence.) Of those who use cannabis, most only do so occasionally. A minority are chronic users and experience chronic A minority are Of those who use cannabis, most only do so occasionally. et al., by Degenhardt One out of ten users will become dependent on cannabis (reported difficulties. region the Nordic 2000). Over one-fifth (21.4%) of young people aged 20-24 from 2000; Hall & Babor, r the important distinction between occasional (Poikolainen et al., 2001). Poulton et al. (2001) also stressed drugs and legal use and dependence. Dependence, not occasional use, was associated with use of other They conclude “occasional use does not appear to cannabis in this longitudinal study. relating problems users is a serious public health issue [but] cannabis dependence among a serious problem, to present dependent of people in Ireland that warrants immediate action” (p544). An estimate for the proportion for of people presenting that the proportion on cannabis was unavailable but Moran et al. (2000) report since 1990. for cannabis use has been between 11% and 16% of those seeking treatment, treatment Moran et al. (2000) stress the importance of distinguishing between lifetime and current use of drugs. the importance of distinguishing between lifetime and current Moran et al. (2000) stress Lifetime telling indicator of frequency. use of a drug is a more or current that recent It is argued use recent if a sample has ever used the drug in question, while experience of a drug simply measures may lifetime measure the last month, etc. Therefore, year, assesses drug experiences within the last a population. within as a poor indicator of trends behaving year to year, fluctuate very little from because of their in this review nonetheless employed rates indicating lifetime use are Prevalence on availability and usefulness in making comparisons (International Scientific Conference widespread drug user. Cannabis, 2002). It is also important to distinguish between use/user and misuse/problem by Bryan et al. (2000) is “a drug user who experiences social, drug user as defined Problem of an excessive compulsion to continue taking as a result psychological, physical or legal difficulties drugs” (p.xii). loss of social well-being for in physical or mental harm or illegal substances in a manner that results (p.xi). the individual, for other individuals, or for society at large” Frequency of Use Frequency (Moran et al., 2000). The Health Behaviours in School-Aged Children (HBSC) Study found much lower (HBSC) Health Behaviours in School-Aged Children (Moran et al., 2000). The al., 2003). Over one-fifth (21.7%) Report (Kelleher et ESPAD by the rates than was reported prevalence to to the HBSC, compared according used cannabis at some point in their lives of 15-16-year olds had steadily days) of cannabis increased use (last thirty finding of 32%. Lifetime and current the ESPAD the most dramatically between use of cannabis increased 11 to 17. Lifetime and current age from in initiation to the drug occurs most frequently suggesting age group, 13-14-year and the 15-16-year use 11%, lifetime use 28.5%). 17-year olds (current found for the rates were this cohort, but the highest Moran et al., 2000). by was 5.9% (reported use among all study participants aged 9-17-years Current T not the data are a number of ways in which are There 15-16-year olds and those in the HBSC study. definition of age-cohort was strictly in terms of the ESPAD strictly comparable, particularly the fact that worth mentioning is that the the study i.e. 1983. Another point those born in the year 16 years before than for cannabis. During the year prior much greater for alcohol and tobacco are comparable figures feeling drunk while of Irish 15-16-year olds had drunk alcohol and 69% reported 89% to the study, 1999). study, at some time (ESPAD quarters of these students had smoked cigarettes about three 60 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 2 third setoffindings centre onthefrequency ofcannabisconsumption andtheprobability ofusing It isveryrare thathard drugs likeheroin are usedbefore cannabis(Fergusson &Horwood, 2000).The Another setoffindingsconcerns thealmostinvariantorder ofadolescents’initiationtodifferent drugs. use cannabisisassociatedwith thelikelihoodofsubsequentusehard drugs. and theriskfactorhasgenerally beenhigh(Kandel,2002).Arelated findingisthatageofbeginningto adolescent cannabisusers.Thiselevatedriskisfoundinallcountries where theissuehasbeen studied involved inprogression tootherdrugs.Thefirstoftheseisthegreater riskofhard drugusefor Three keyfindingshaveplayedanimportantpartintheacceptanceofideathatcannabis is longstanding oneandhasbeenquiteinfluentialindrugpolicy inmanycountries(Morraletal.,2002). cocaine andheroin. Thisconcern abouttheriskofprogressing tomore dangerous substancesisa argued thatuseofcannabisincreases youth’s riskofinitiatingmore dangerous drugssuchas other drugs.Inthedebatesondecriminalisationandmedicinal useofcannabis,itisoften One ofthemostcontroversial issuesregarding cannabisconcernsitsrole intheprogression touseof Cannabis UseandSubsequentofOtherDrugs not report cannabisuserarely reported theuseofotherdrugs(Perkoniggetal.,1999). participants were continuous usersandmore soiftheyexperienceddependence.Studentswhodid (including ecstasy),hallucinogens6.1%,andcocaine5.2%.Thesepercentages increased ifthe use ofotherillicitdrugs(notnecessarilysimultaneously),9.4%admittedtothestimulants In alongitudinalstudyofGermanadolescentsaged14-17years,17.5%cannabisusersreported the however, were unlikely toengageinprolonged orheavyuseofthesedrugs. use cocaineand9%6%respectively useecstasy(Cohenetal.,2001).Thesepolydrugusers, r use alcohol,tobacco,andotherdrugs(paraphrased,p325).Theauthorsofthe“Three Cities”study for confoundingdemographicandneuroticism factors,anytypeofcannabisuserwasmore likelyto used likely toabuseorbedependentuponsedatives,stimulants,opiates,alcohol.Eventhosewho Degenhardt etal.(2001)foundthatthosewhoexperiencedcannabisdependenceorabusewere more distinctions between“recreational” and“problematic” polydrugusers. in anIrishcontextandcallsforfurtherinvestigation,namelytodrawcomparisonsmake (36.5% ofrespondents). Keane(2001)concludesthatthere are gapsintheknowledgeofpolydruguse ‘confirmed’ polydrugusers,cannabisandalcoholwere reported asthemosttypicalcombination When polydrugusewasdefinedas“usingtwoormore drugsinthesame24-hourperiod,” among41 combination withMDMA(ecstasy)andalcohol,buttoamuchlesserextent. benzodiazepines (Sinclairetal.,2001).Ofthoseseekingtreatment, cannabiswasalsoused in and benzodiazepineswasthesecondmostcommontriageofdrugsafterheroin, methadone,and of twodrugsusedtogetheronadailybasiswasheroin andcannabis(NDTRS,2002).Cannabis, heroin, According totheNationalDrugTreatment ReportingSystem(NDTRS),themostcommoncombination al., 2001)as“theuseofdifferent substancesanddifferent combinationsatdifferent times”(p161). Polydrug useisdefinedinthereport oftheDrugMisuseResearch DivisiontotheEMCDDA(Sinclairet Other DrugsUsedinCombinationwithProduct eport thatamongregular cannabisusersinAmsterdam and SanFrancisco,9%and8%respectively cannabis were atgreater riskforalcoholabuseandproblems withotherdrugs.Aftercontrolling Public HealthRisksofCannabisUse:EpidemiologicalEvidence NACD 2004 An Overview of Scientific and other Information on Cannabis 61 Public Health Risks of Cannabis Use: Epidemiological Evidence Use: Epidemiological Cannabis of Risks Health Public Chapter 2 Chapter drugs like heroin. A common finding is that the more frequent use of cannabis is associated with use of frequent is that the more A common finding drugs like heroin. & Horwood, 2000). drugs (Fergusson of use of hard likelihood greater with explaining these and ‘gateway’ hypotheses have been concerned The ‘stepping stone’ use ‘causes’ or leads unavoidably to stone’ theory suggests that cannabis associations. The ‘stepping evidence to suggest that the is no pharmacological there serious drugs. However, the use of more drugs (Corrigan, 1994; Rigter & to other of cannabis would inevitably lead to a progression properties statistical association between cannabis use is a strong as noted above there 2002). However, van Laar, of other illicit drugs. On the other hand it is known that many during adolescence and subsequent use heavy use of cannabis or to other illegal to either progress young people try out cannabis and do not 2002). substances (Rigter & van Laar, risk users may also use other drugs due to predisposing The ‘gateway’ theory suggests that cannabis acknowledges cannabis primes the user into taking factors or experience. The gateway hypothesis than one and also that more not direct are other substances but that the mediating influences (alcohol of legal substances also acknowledges the role pathway may be involved. The gateway theory evidence adolescents to using cannabis in the first place. Emerging and tobacco) predisposing in exactly the same and withdrawal processes brain reward suggests that cannabinoids not only affect can be sensitisation with amphetamine and morphine cross way as other addictive drugs but also that that long-term use of cannabis exposed to THC suggesting repeatedly induced when animals are & Pontieri, 1997; in certain individuals (Tanda might enhance vulnerability to addictive substances & Simon, 2001). Taghzouti Lamarque, is that social disadvantage and low levels of parental One elaboration of the gateway hypothesis themselves influential in are associated with early cannabis use and that these factors attachment are indications that this may be part of the are 2002). There drugs (Rigter & van Laar, to other progression is also some indication that genetic susceptibility to drugs There story but not the complete picture. 1991). (Sher, cannabis to other substances from may be at least a contributory factor in the progression context in which cannabis is used and obtained. factor may be the social An important environmental barriers and inhibitions against the use of perceived It may be that access to cannabis may reduce 1990). Another factor that may access to such drugs (Bailey & Hubbard, other drugs and the perceived is some indication that non-conforming is personality make-up. There be involved in progression to use drugs, i.e they may be propensity adolescents may initially try out cannabis as part of a broader to take risks than their peers; they may have such positive experiences novelty-seeking or ready more the risk of other illicit drugs (Petraitis et al., 1995). with cannabis that they start to underestimate (See further discussion in chapter 4.) at least some version of the ‘gate-way’ theory. is a considerable body of evidence favouring There and alcohol use was demonstrated, cigarette Merrill et al. (1999) showed that although no causal effect with the was associated with the likelihood of marijuana use and marijuana use was associated considered behaviours were likelihood of other drug use, even after selected other risk and protective New Zealand showed individuals using cannabis among high school seniors in the US. Findings from than 59 times higher of other illicit drug use that were had hazards than 50 occasions a year on more factors and non-users. After adjustment for co-variate factors, including childhood factors, family to the onset of other forms of illicit related strongly adolescent lifestyle factors, cannabis use remained 2000). & Horwood, drug use (Fergusson 62 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 2 in theEUthanAustraliaor USA(Table 4). methodologies andpopulations, theavailabledatasuggeststhatcannabisuseislessprevalent (Rigter &vanLaar, 2002). Althoughcomparisonsbetweencountriesare hampered bydifferent Approximately 18%ofthegeneralpopulationinEUhave triedcannabisatsometimeintheirlives 1999). Europe prevalence estimatesare nearingthoseoftheUnitedStatesandCanada(Perkonigg etal., 2000). However, alongitudinalstudyofadolescentsinGermanysuggeststhatatleastsomeparts The useofcannabisisevenmore prominent intheUSAandAustralia(ESPAD, 1999; Hall&Babor, increase intheuseofillicitdrugsotherthancannabis. Estonia, Italy, andLithuania.Inaddition,nearlyhalf oftheESPAD countries were experiencingan pronounced increase includedPoland,CzechRepublic(puttingitonparwiththeUnitedKingdom), for thosewiththehighestrates,UnitedKingdomandIreland. Countriesinwhichthere wasa finding isthatfrom 1995to1999, almostallcountriesexperiencedmountingprevalence rates,except in lifetimeuseofcannabis,whileFrancehadthehighestratelast30days.Aninteresting of Cyprus,Romania,Faroe Islands,Finland,andSweden.InEurope, theUnitedKingdomrankedfirst and Slovenia.Ontheotherhand,cannabisconsumptionwasonlyfoundin1%-2%ofpopulations of cannabisamong15-16-yearoldswere Ireland, theUnited Kingdom,France,CzechRepublic,Italy, As aforementioned, theESPAD Report(1999)foundthatthecountrieswithmostwidespread use cannabis reside inaruralarea ofIreland (Bryanetal.,2000). who haveeverusedcannabisreside inanurbanarea ofIreland while9.9%whohaveeverused Lifetime prevalence ratesofcannabisuseare higherinurban locations(Moranetal.,2000)–14.5% Geographical DistributionofUse drug use. of acommonfactor–drug-usepropensity –influencingtheprobability ofbothcannabisandother the observedassociationbetweencannabisandotherdrugscouldinsteadbeexplainedasresult likely tousecocainethanwere thosewithnohistoryofmarijuanause.Morraletal.(2002)reports that smoking. Amongyoungpeoplewithacocaineopportunity, thosewhohadusedmarijuanawere more an opportunitytodosohadoccurred. Opportunitytousecocainewasassociatedwithpriormarijuana non-users tohaveanopportunitytrymarijuanaandwere more likelytoactuallyusemarijuanaonce W perceived barriersagainsttheuseofotherillegaldrugsandprovide accesstothesedrugs. which cannabisisusedandobtained–inparticular, earlyaccesstoanduseofcannabismayreduce environmental factors.Theassociationmayarisefrom the effects ofthepeerandsocialcontextwithin abuse/dependence cannotsolelybeexplainedbycommonpredisposing geneticorshared r abuse, conductdisorder, majordepression, and socialanxiety)hadonlynegligibleeffects onthese known riskfactors(early-onsetalcoholortobaccouse,parental conflict/separation,childhoodsexual 5.2 timeshigherthanthoseoftheirtwinwhodidnotusecannabisbefore age17years.Controlling for years hadoddsofotherdruguse,alcoholdependence,andabuse/dependencethatwere 2.1to L esults. Theyconcludethatassociationsbetweenearlycannabisuseandlaterdrug ynskey etal.(2003),inastudyofAustraliantwins,foundthatthosewhousedcannabisbyage17 agner andAnthony’s (2002)results indicatedthatusersoftobaccoandalcoholwere more likelythan Public HealthRisksofCannabisUse:EpidemiologicalEvidence NACD 2004 An Overview of Scientific and other Information on Cannabis 63 Public Health Risks of Cannabis Use: Epidemiological Evidence Use: Epidemiological Cannabis of Risks Health Public Chapter 2 Chapter Adapted from Data from the International Conference on the International Conference Data from Adapted from ends in Prevalence and Patterns of Use ends in Prevalence estern – Nations Finland 10 3 SwitzerlandGreeceSwedenGermany (‘East’) 19 13 11 13 5 4 5 1 BelgiumGermany (‘West’)IrelandSpainNetherlands 21 21 20 19 20 6 ? 9 6 7 CanadaEngland & WalesDenmarkFrance 27 29 24 23 9 7 4 8 CountryAustraliaUSA Lifetime Use % 39 Use % Last Year 34 18 8 able 4. Prevalence Rates of Cannabis Consumption in the General Population of in the General Population Rates of Cannabis Consumption able 4. Prevalence espondents aged 15 to 35 or 40 years) is compared, Ireland, along with England and Wales, had the along with England and Wales, Ireland, espondents aged 15 to 35 or 40 years) is compared, Tr being young, being white, having lower of cannabis use are Factors identified as predictors not attending any religious educational and occupational expectations, living in an urban area, high school), services, living alone, having a father or a mother with advanced education (at least on Cannabis, 2002). Scientific Conference (International being male and living with only one parent years. Union has doubled in the past 10 indications that cannabis use in the European are There people aged 15-64 years) have tried cannabis at least once (Hartnoll, 20% (50 million Approximately 1995 to 1999 are 2002, paraphrased, p4). The rates of cannabis use among adolescents for the period rates among Union. Cannabis prevalence in the European among member states converging in countries and increasing in historically higher-use stabilising or decreasing adolescents are lifetime use among in Ireland Report). Results showed that those with past low rates of use (ESPAD T W The studies quoted show lifetime use among the general population to vary from 10% in Finland to The studies quoted show lifetime use among the general population to vary from of 20% for rate mid-way in the table with a prevalence approximately appears 39% in Australia. Ireland the EMCDDA for ‘young adults’ (defined as lifetime use in the general population. When data from r (use in last year) cannabis consumption in the EU at 18% rate for recent highest prevalence (EMCDDA, 2001). Cannabis, 2002. 64 An Overview of Scientific and other Information on Cannabis NACD 2004 and last-30-dayprevalence ratesofcannabisusersaged18-24,25-34,35-44,45-54and55-64 A review ofIrishsurveysconfirm thatthisgenderdifference generalisestothelifetime, last-12-month treatment forsubstanceabuse(Westermeyer &Boedicker, 2000). drug forfeweryears,havinglegalproblems associatedwithdrugs,andhavingspentlessdaysin use aswelllessproblems associatedwithusewhencompared withmen,includinghavingusedany patterns ofcannabisconsumptionare more pronounced inmales.Women demonstratelowerlevelsof of bothpatternsproblematic usenearlydoubledforbothsexes.Still,mostresearch indicatesthat indicators ofabuseanddependencewere included.Betweenbaselinedataandfollow-up,therates Perkonigg etal.(1999)reported nosignificantdifference betweenmalesandfemales evenwhen this findingtotherelatively young ageofthesampleandtheirmildexperiencewithdrug. with theearlystages.Inthisgroup, there wasnosignificant genderdifference. Theauthorsattribute classified as‘one-timeonly,’ ‘repeated use,’and‘regular use,’focusingontheriskfactorsassociated For instance,Hofleretal.(1999)targeted adolescentsaged14-17whosecannabisexperiencewas However, there issomeresearch thatfailstofindanygenderdifferences ofstatisticalsignificance. Cannabis, 2002;ESPAD, 1999;vonSydowetal.,2002;BrinkleyCoffey etal.,2002). consumption ismore prevalent amongmalesthanfemales (InternationalScientificConference on Most studiesonthedemographicsofcannabisuse,abuse,anddependenceindicatethat Age andGenderofUsers Characteristics andBehavioursofUsers drug. ThiswasalsotrueintheUnitedKingdom. showed thatover90%ofIrish16-yearoldswhohadusedillicitdrugsreported cannabisas theirfirst 15-16-year oldshaddecreased from 39%in1995to32%1999(ESPAD, 1999).TheESPAD studyalso Chapter 2 1 use intheyouth populationcomesfrom population studies.Althoughthere are alimitednumberof 50, respectively (NationalInstituteonDrugAbuse,2002).The mostconvincingevidenceofincreased increases withagebetween8th-,10th-,and12th-graders,reaching percentages of20,40,andalmost In theMonitoringFuture Study, datacollected inUSschoolsrevealed that theuseofcannabis age (DrugsPrevention.net, 2002). some pointintheirlives,compared with83.5%ofthoseaged22-25and90.3%26-30years Agency inNorthernIreland found that85.9%ofadultsaged18-21reported havingtakencannabisat ages of20and30thendeclinesasoneheadstowards middleage.Indeed,theHealthPromotion typically declineswithagebeginninginearlyadulthood.Use usually reaches itspeakbetween the average, beganusingat12.7,compared withboysat12.2yearsofage.Cannabisconsumption Brinkley etal.(1999).Girlshadasignificantlyolderageofonset whencompared withboys;girlsonthe lowest initiationageofanyillicitdrug.Themeanonset is12.5yearsofage,according to highest riskperiodofbecomingdependentonthedrug(Perkonigg etal.,1999).Cannabishasthe literature, thehighestriskofuse andinitiationoccursbetweenages14-18atage16beginsthe The experienceofcannabisisprimarilyayouth-basedphenomenon.Basedonreview ofcannabis to femalesforthoseaged11-12,13-14,15-16and17years(Moranetal.,2000). lifetime, last-12-monthandlast-30-dayprevalence ratesforcannabiswere higherformalescompared et al.,2000).Thedatafrom the1998HBSCstudyofthoseagedlessthan18yearsshowsthat last-30-day prevalence rateformales andfemalesin thisgroup converge at0.5. While thelifetime andlast-12-monthprevalence ratesshowagenderdifference inthe55-64 yearagegroup, the Public HealthRisksofCannabisUse:EpidemiologicalEvidence 1 (Moran NACD 2004 An Overview of Scientific and other Information on Cannabis 65 Public Health Risks of Cannabis Use: Epidemiological Evidence Use: Epidemiological Cannabis of Risks Health Public Chapter 2 Chapter eceiving their first drug (typically cannabis) from friends or siblings, compared with less than 5% who friends or siblings, compared from eceiving their first drug (typically cannabis) cannabis use, of those Dublin pupils reporting study, In a related a stranger. eported getting it from The presence of psychoactive material in cannabis undoubtedly has an effect on the behaviour of an undoubtedly has an effect of psychoactive material in cannabis The presence this individual, but the extent to which this occurs has yet to be determined. Factors complicating namely and the tendency for cannabis to be used with other drugs, individual differences issue are of cannabis on behaviour. to isolate the effect alcohol, making it difficult violence associated with cannabis use suggests that perceived on cannabis, Nelson (1993), in a review of cannabis often confused with effect a psychological is actually a manifestation of “panic reaction”, makes cannabis users state and lassitude that their depressive He reports behaviour. aggressive has been disputed. In a New Zealand sample of young This mellowing effect unlikely violent offenders. cannabis dependence, adults, the following contributed to their risk of committing violent offences: 10%. Any combination of two of these factors 28%; alcohol, 11%; and any form of schizophrenia, Risk Behaviours Associated with Use Friends or those the user knows well are often cited as their means of obtaining the drug as well. often cited as their means of obtaining Friends or those the user knows well are in which adolescents experimented consistently named as the primary social group “Friends” were users, Cities Study’, examining the behaviours of long-time drug with or used cannabis. In the ‘Three (Cohen et al., 2001). The amongst friends the first time they used cannabis eight out of ten were 80% in approximately that revealing literature on Cannabis (2002), reviewed International Conference than 75% was initiated by friends or acquaintances. More of cases, users’ first experience of cannabis Report (1999) admitted assessed in the ESPAD of the students using drugs in 19 of the countries r r that the cannabis was ‘shared a friend and 62% reported 64% had said they obtained the drug from peers/friends’ influence along with curiosity, of friends’ (Brinkley et al., 1999). Similarly, group a around Brinkley et al., 1999). cannabis use (Kuipers & Zwart, 1999; is an important factor leading towards the with which adolescents use cannabis. However, another social group Elder siblings may represent quite low. rates of siblings of these users are Report finds that the cannabis prevalence 1999 ESPAD high cannabis drug users have corresponding higher rates of sibling Those countries with relatively also use that 17% of their siblings reported cannabis users in Ireland rates. For instance, prevalence of sibling cannabis This low percentage with the average of 6% for all countries). cannabis (compare for consumption. acting as a social group evidence against older family members users provides Social Groups Where Product Available/Used Product Where Social Groups studies addressing the general population, those that exist find the youngest age group (varying age exist find the youngest age group the general population, those that studies addressing of cannabis consumption (Kelleher et and young adults) have the highest rates ranges of adolescents the Commission to the Council and the 2000) The Communication from al., 2003; Moran et al., that between Action Plan to Combat Drugs (1999) reports Union Parliament on a European European have at least experimented population and 20% of the younger population 1% and 8% of the total with cannabis. showed that lifetime, last-12-month and last-30-day the 1998 HBSC survey in Ireland Data from The 1998 old to the 17-year old age group. the 11-12-year steadily from rates increased prevalence last-12-months and last-30- rates (lifetime, that prevalence SLAN and KABI surveys of adults showed 18-24 years to 55-64 years (Moran et al., 2000). from in each successive age group days) decreased 66 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 2 severe effects mayoccurin babiesborntoheavierusers. use ofcannabis.Thewomeninthisstudyusedcannabisonce perweekorless,suggestingthatmore at riskforperinataldeathorinneedofcare; however, thisstudyislimitedbyfrequency ofmothers’ were showntobeinsignificant.Cannabisuseduringpregnancy doesnotseemtoputtheunbornchild than babieswithnon-usingmothers.Smalldifferences were alsodetectedinbirthweight,butthese Babies borntothesemothershadsignificantlyshorterbirthlengths andsmallerheadcircumferences pregnant women,thoughresearch indicatesadverseeffects are minimal(Fergusson etal.,2002). Another particularlyvulnerablegroup toconsiderare unbornchildren ofcannabis-consuming were exacerbatedbycannabisconsumption. several studiesreviewed byJohns(2001)positivesymptoms,namelyhallucinationsanddelusions, evidence thattheuseofcannabisaggravatessomesymptomsinpatientswithschizophrenia. In pronounced andthere issupportforcannabisactingasa risk factorforthedisorder. There isalso of cannabis.Theprevalence ofcannabisuseintheschizophrenic populationis,however, well general, there hasyettobeaclearcauseandeffect relationship withtheuseandabuse/dependence especially schizophrenics. As wasdiscussedinChapter1,withinthecontextofmentalillness There isaconcernaboutthe useofcannabisandabuse/dependenceinthementally-illpopulation, Special ConcernsaboutVulnerable Groups the chancesofsuchunwantedeffects aspregnancy andthetransmissionofaninfectiousdisorder. r less often(Castillaetal.,1999).Sexualriskbehaviour–sexwithmore thanonepartnerandlackof consumption were more likelytohavemultiplesexualpartnerscompared withthose usingcannabis drugs withriskysexualbehaviour. Spanishadultsaged18-39withhigherfrequencies ofcannabis There hasalsobeenasignificant associationbetweentheuseofcannabisandotherpsychoactive non-significant changesindepression andanxietyscores. aggressive responding returned topre-withdrawal levelsafter28daysandwere paralleled bysmall, marijuana abstinencecompared tocontrols andtotheirown pre-withdrawal data.Theseincreases in showed thatchronic marijuanausersdisplayedmore aggressive behaviourondaysthree andsevenof Kouri etal.(1999)investigatedtheabstinencesyndrome associatedwithchronic marijuanauseand (Chapter 1containsamore detaileddiscussiononcannabisandmentalillness.) r benzodiazepines, andcocaineappeared toinduceviolentreactions inusers,thesamecausal failed topredict violenceandaggression bytheuseofcannabis. Whilealcohol,antidepressants, (Arsenault, 2000reported bytheInternationalConference onCannabis,2002).Gilletetal.(2001)also conduct disorder, suchasdelinquency, mayspawnviolencemore sothantheuseofcannabis those experiencingcannabisdependence.Itissuggestedbythestudythatfactorsassociatedwith of cannabis–priortoanactviolencethatwasresponsible fortheincreased riskofviolenceamong greatly elevatestherisk.However, itwasathird factor, thepresence ofconductdisorder –nottheuse occur withcannabis use:lowersocio-economic status;malegender;poorfamilial relationships The followingcharacteristicsand behaviourshavebeenfoundconsistentlyinseveralstudies to co- Tr egular condomuse–tendedtooccurmore frequently with thosethatwere “high”,thusincreasing elationship wasnotfoundforcannabis. ends inCharacteristics/Behaviours ofUsers Public HealthRisksofCannabisUse:EpidemiologicalEvidence NACD 2004 An Overview of Scientific and other Information on Cannabis 67 cannabis user does not exist” (Rigter & The Public Health Risks of Cannabis Use: Epidemiological Evidence Use: Epidemiological Cannabis of Risks Health Public Chapter 2 Chapter (particularly with the mother); mental illness; use of alcohol, tobacco and other illicit drugs; adoption of mother); mental illness; use of alcohol, tobacco (particularly with the friends; unemployment; easy lifestyle; poor school performance; substance-using an anti-conventional 2001; McGee, (Brinkley et al., 1999; Poikolainen, in an urban area and residing availability of drugs; 2002). et al., 1998; von Sydow et al., Hall, 2000; Morrell & 2000; Lynskey and interpersonal factors that sociodemographic, personality, Some authors have suggested have simply those of individuals who from or abuse/dependence differ use associated with the regular in a study of the early stages of cannabis consumption experimented with the drug. For instance, spanning a wide range of users such as low self- among German adolescents, typical characteristics many other variables did not confirmed, however, use were esteem, poor competence, and peer drug et al., 1999). The use of other illegal drugs, a history of generalise to these experimental users (Hofler first or occasional use of failed to predict education, and residence gender, conduct disorder, and dependence, include use, to abuse from progression characteristics predicting cannabis. Similarly, socio-economic status, use of other illicit (but not licit) younger age, a disadvantaged male gender, Sydow et al., 2002). (von problems drug use, and maternal affective future drugs, attitudes towards as simply listed here are importantly the characteristics, of cannabis users The behaviours, and more would it in sample populations. The list is by no means conclusive nor those occurring most frequently many All levels of users come from of accuracy those that will use cannabis. a high degree with predict of cannabis user (or any drug user) would be a single profile and to create backgrounds different quote “ impossible. This is summed up by the following van Laar, 2002). To complicate matters further, Kuipers & Zwart (1999) discovered a recent trend in the trend a recent Kuipers & Zwart (1999) discovered complicate matters further, 2002). To van Laar, those of the non-using cannabis users in the Netherlands to resemble characteristics of regular normalisation of cannabis use in of the continued a result cannabis population. This is presumably but nonetheless blurs the distinction between those in this review), (discussed elsewhere many areas who use drugs and those who do not. mental and behaviours of users comes from of information on the characteristics A major source or the drug the question of which came first, the illness McGee et al. (2000) addressed health research. with afflicted use. In a longitudinal study of New Zealanders aged 15-21, those youngest in the sample as to use cannabis. However, than those without a disorder likely four times more mental illness were of a as well; the presence consumption increased rates of cannabis the sample aged, the prevalence is The implication of substance use in the older age groups. predictor failed to be a mental disorder use to cannabis mental disorder of risk lies from that among younger people “the primary direction the opposite conclusion in a study on Poikolainen et al. (2001) reaches (p500). rather than the reverse” the former study deals with all levels of cannabis of initiation to cannabis use. However, the correlates than a few times. use, while the latter focuses primarily on those whose use does not exceed more plays in the lives of those who use cannabis, the environment that is no doubt of the central role There the possible impact of genetics on users. Kendler and Prescott has explored research recent however, pairs of monozygotic (1998) assessed lifetime cannabis use, heavy use, abuse, and dependence among that cannabis use is attributed to both genetic indicate and dizygotic twins. The hertitability results but the authors suggest that heavy use, abuse and dependence influences, and environmental genetic make-up. A study in Australia of of the individual’s a result solely symptoms of cannabis are cannabis use and drug use escalation among monozygotic and dizygotic twins concluded that early genetic later drug use and abuse/dependence cannot solely be explained by common predisposing 68 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 2 (del Rioetal.,2002). Postmortemresults inStockholm showedthatdeathsamong thecannabisusers involving fatally-injured drivers,thefourth-most-commondrug, afteralcohol,cocaine,andopiates decade (Galeaetal.,2002).Employing bloodsamples,cannabiswasdetectedin2.2%ofthe cases positive toxicologyhasactually falleninthemid-1990safteranincrease intheearlierpartof with cocaine,opiates,andalcohol, were detectedinnearly everycase.Indeathsbyguns,cannabis- firearms andmotorvehicleaccidents. AmongdeathsduetodrugsinNewYork City, cannabis,along Other areas where therole ofcannabisasanindirect cause ofdeathhasbeenresearched includes direct orindirect causesofdeathintheIrishreport totheEMCDDA(Sinclairetal.,2001). is commonforseveraldrugstoappearononecertificate.Cannabis wasnotmentionedinrelation to the years1993to1996.However, thecertificateslistalldrugsthatwere believed tocausedeathandit r The HouseofLords Reporton cannabis(2000)reports thatinanexaminationofthecausesdrug- cannabis in10,5and1instances,respectively. while alcohol,alcoholandmedicinaldrugs,oronlydrugswasdemonstratedtogetherwith be theonlydruginpostmortemsamples24cases;8ofthese,cannabiswasfinding, illicit druguseintheStockholmarea. Duringthefour-year periodof1987-1990,cannabiswasfoundto (19%), andFinnish(12%)cases.Rajsetal.(1992)reported datafrom theregister ofdeathsrelated to However, tetrahydrocannabinol wasobservedinmanyoftheDanish(31%),Norwegian(25%),Swedish majority oftheaddicts,butinnocasewascannabisreported asthemaindrugresulting indeath. determined byautopsyandtoxicologicalanalysis.Heroin/morphine wasthecauseofdeathin addicts inDenmark,Norway, Sweden,Finland,and Iceland.Thedrugspresent inthedeceasedwere Steentoft etal.(2001)determinedthedrugsinvolvedinpoisoningsresulting inthedeathsofdrug influence ofcannabisonpremature mortality. Scientific Conference onCannabis,2002).There is,however, someevidencethatsuggeststheindirect Addiction hasnotyetdefinedcannabisintermsofits“problematic use”(Nelson,1993;International contracting aninfection.Itisforthisreason thattheEuropean MonitoringCentre for DrugsandDrug There havebeennodeathsasadirect result ofcannabisuse,suchasthrough pulmonarydiseaseor Deaths (Direct andIndirect) emergencies in2001(NationalInstituteonDrugAbuse,2002). Ireland. –intheUSmarijuanawasidentifiedasafactorcontributingtoover110,000ofhospital number ofemergency admissionsrelated toaccidentsassociated withcannabisabuseisunknownin 5.0% offirstadmissionstoin-patientpsychiatrichospitalswere drug-related (Moranetal.,2000).The induced bycannabisisadirect causeforpsychiatricadmission.InIreland, 3.6%ofalladmissionsand There islittledocumentationofhospitalemergencies related specificallytocannabis.Acutepsychosis Hospital Emergencies Indicators ofHealthConsequences social contextinwhichcannabisisusedandobtained(Lynskey etal.,2003). or shared environmental factorsandthattheassociationmayarisefrom theeffects ofthepeerand elated deathsinEnglandandWales, cannabis appeared ondeathcertificates35timesthroughout Public HealthRisksofCannabisUse:EpidemiologicalEvidence NACD 2004 An Overview of Scientific and other Information on Cannabis 69 Public Health Risks of Cannabis Use: Epidemiological Evidence Use: Epidemiological Cannabis of Risks Health Public Chapter 2 Chapter raffic Accidents raffic elationship between the frequency of cannabis use and traffic accidents as part of a longitudinal study and traffic of cannabis use elationship between the frequency T 1970) gave consideration to the link between The Le Dain Commission (Canadian Government, to believe that the “short-term effects was reason that there cannabis use and driving and concluded EU Member States the concern across of driving”. The increasing the hazards of cannabis increase conducted review accidents was highlighted by a literature in traffic drug use may play about the role Monitoring for the European Board Division of the Health Research by the Drug Misuse Research between drug use, Drugs and Drug Addiction (EMCDDA) which looked at the relationship on Centre accidents (Gemmell et al., 1999). Field studies demonstrated that cannabis driving and traffic impaired drivers. Assessment of the in fluid samples taken from drugs discovered was one of the most prevalent in the of cannabis was found to be complicated by the fact that alcohol was also present causal role likely to be found that cannabis, when mixed with alcohol, is much more majority of cases. The review a risk factor than when consumed alone. as well as that of other health indicators accidents, to cannabis and traffic pertaining The research use as the cause of various negative outcomes, found in this section nearly always cites polydrug list of drugs cannabis usually heads the substances. However, typically alcohol used with one or more and Horwood (2001) demonstrated a significant found in combination. Fergusson that were r with the amount of accident increased in New Zealand. The likelihood that one was involved in a traffic for confounding factors, such as risky/illegal driving after controlling cannabis consumed. However, the association between cannabis use and driving violations, behaviour and casual attitudes towards study found that alcohol caused a significant accidents became non-significant. A German active traffic & Terry, users (Wright to regular cannabis users relative deterioration in performance among infrequent for dizziness. scores by significant changes in self-reported mirrored 2002). These changes were driving skills are of THC and alcohol on higher-level of low doses Another study found that the effects minimal (Lamers & Ramaekers, 2001). that epidemiological studies, such as the one on cannabis use and driving, it was found In a review for cannabis-using drivers in motor likely to indicate a very limited role more mentioned above, are on Cannabis, 2002). Experimental studies, on the vehicle accidents (International Scientific Conference suggest that the other hand, typically find significant impairment in ability when cannabis is used. They and call for more, indicators (such as self-reports) biased due to unreliable epidemiological studies are studies. carefully-controlled of THC presence One study that did use blood samples to determine level of intoxication found the crashes (Longo et al., 2000). to driver culpability in either single-or multiple-car only was not related of cannabis-using a lower percentage where group, with the drug-free striking is the comparison More were unexpectedly violent compared to deaths among other drug addicts. The proportion of suicides, proportion deaths among other drug addicts. The to unexpectedly violent compared were a non-violent only one died from high. Among the 24 cannabis users, 10 out of 24, was particularly to a total of 26% of the of violence, compared 23 (96%) died as a result cause, while the remaining cannabis during the same period. Eight of the 24 of 13,417 investigated postmortems number entire traffic and five from drowning alcohol intoxication, one from – two from users died in accidents with cannabis-influenced drivers) of motor vehicles, and 2 as passengers accidents (3 as drivers (Rajs et al., 1992). 70 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 2 make asmallcontribution Hall &Babor(2000)takeamore oppositionalstanceontheissue,claimingthatcannabis“seemsto the factthatthesesubstancesbothcause,inmain,reversible perceptuo-motor deficits”(p2). are more duetothemethodsandcircumstances oftheirusebyaminorityindividualsratherthan used “…problems causedbyalcoholandcannabisinrelation tomotorvehicleaccidents,inparticular, plays arelatively minorpartinvehicleaccidents,thatitismore amatterofthecontextinwhichitis coexistence ofalcoholandTHCintheanalysesdrivers’blood.Heimpliesthatdrugitself Nelson (1993)recognises thedifficulty indeterminingthe effects ofcannabisondrivingduetothe not reached byanyoftheparticipantsintheirstudy, cannabiscouldresult inincreased culpability. not significantlygreater thanthesoleeffects ofalcohol. Longo etal.cautionthatinextreme doses, alcohol andcannabisusedtogetherresulted inaugmentedculpabilityfordrivers,thecombinationis drivers were deemedculpableforthecrash.Thisdifference, however, wasnotmeaningful.Although r concluded thatmethodsfordetecting cannabinoidsinbloodspecimenswere inadequateandwould blood specimensanalysedbythe different methods,exceptforcannabinoids”(p.89).The authors benzodiazepines. Thestudyfoundthatresults showed“excellentagreement fordrugdetectioninthe four ormore drugspresent. Themostfrequent drugsfoundwere cannabis,amphetaminesand than onedrug.66%oftheconfirmedspecimenscontainedtwo ormore drugs,and10%confirmed specimens were foundtobe positive; 23specimenswere positiveforonedrugclassand48more specimens testedforthepresence ofadrugduring2000.Ofthese,34bloodspecimensand37urine (Drugnet Ireland, 2002).Astudy conductedfortheMBRSbyFlynnetal.(2001)analysed78 out research ontheepidemiologyandtrends inregard todrivingundertheinfluence ofdrugs Government’s StrategyforRoadSafety1998-2002,theMedicalBureau ofRoadSafety(MBRS)carried The linkbetweendrugsanddrivinghasrecently beenafocusofpolicyinIreland. Aspartofthe were slightlygreater thanwithcannabisalone(Sextonetal., 2002). The effects ofalcohol(atadose ofjustmore thanhalftheUKlegallimit)andcannabistakentogether driver capabilityfollowingtheingestionofcannabisorandalcoholtogether. deteriorated withincreased doselevel.Intermsofroad safety, thestudyshowedaclearworseningof bend (tracking),where theirperformancedeteriorates.Thestudyfoundthattracking unable tocompensateforthelossofcapabilityinsomepsychomotorskillssuchasstayinglaneona of cannabisare aware oftheirimpairment,attempttocompensate bydrivingmore cautiously, butare clinical trials.Itconfirmedtheresults ofprevious studieswhichshowedthatdriversundertheinfluence assessing theeffects ofcannabis andalcoholondrivingperformanceincontrolled experimental An experimentalstudybytheUKTransport Research Laboratorydemonstratedthepracticabilityof Institute onDrugAbuse,2002). the hospitalemergencies in2001–15%ofthepatientswere betweentheagesof12and17(National Drug AbuseWarning System(DAWN)identifiedmarijuanaasafactorcontributingtoover110,000of ability, itisdifficult todeterminetheextentofthisinfluenceontraffic accidents.Datafrom theUS’s While itisnotedthatcannabishasadversebehaviouralandcognitiveeffects thatcanimpairdriving the combinedintoxicatingeffects ofalcoholandcannabis(Gieringer1998,citedinHall&Babor). equire furtherspecialattention. Public HealthRisksofCannabisUse:EpidemiologicalEvidence in itsownright to motorvehicleaccidents”,againexpressing concernover NACD 2004 An Overview of Scientific and other Information on Cannabis 71 outside the Eastern Regional Health 2 Public Health Risks of Cannabis Use: Epidemiological Evidence Use: Epidemiological Cannabis of Risks Health Public Chapter 2 Chapter eatment for illicit drug use only. r egion, however, cannabis misuse decreased from 70% (1996) to 58% (2000) of those seeking 70% (1996) to 58% (2000) of from misuse decreased cannabis egion, however, egards to alcohol testing. Cannabis intoxication, the commission pointed out, “is still unrecognisable intoxication, the commission pointed to alcohol testing. Cannabis egards Authority area (NDTRS, 2002). Several health board areas experienced notable increases in cannabis experienced notable increases areas (NDTRS, 2002). Several health board Authority area for one-half were of those seeking treatment, Board, misuse. For instance, in the Southern Health 33% in from in 2000. Cannabis misuse increased with two-thirds in 1996, compared cannabis problems 44% in and from Health Board, in 2000 in the Mid-Western 1996 to 53% of those seeking treatment In the South Eastern Health Board region. Health Board 1998 to 61% in 2000 in the North Eastern r 92 from almost trebled number seeking treatment during that time the absolute However, treatment. is a fairly stable and there has remained Health Board to 247. Cannabis misuse in the North Western (NDTRS, 2002). area Health Board for any drug in the Western low number of those seeking treatment drug use for an accurate indicator of problematic considered are for treatment Although requests The EMCDDA (1998) describes drug treatment is needed here. of caution most substances, a word and a valuable public health tool (paraphrased, NDTRS, 2002). in assessing needs data as effective counselling. any cannabis users do not request that most problematic Rigter & van Laar (2002) reports with other when compared Hall & Babor (2000) deducted that few cannabis users seek treatment not as intense as those produced of cannabis are dependent drug users simply because the ill effects alone for cannabis problems there rarely are for treatment by opiates and stimulants. Those presenting mental disorder. and/or a non-drug related other substance disorders from usually suffering and are primarily for cannabis troubles patients being treated For instance, in the Netherlands, one in three alcohol and cocaine (Hall & Swift, 2000 quoted in namely with also experienced other drug problems, on Cannabis, 2002). the International Scientific Conference as an indicator of Admissions to in-patient psychiatric hospitals can also be examined with causation community intervention for drug drug use. Despite policies favouring non-residential problematic on the rise. First admissions with a drug-dependence are admissions dependence, drug-related This sum of all health boards). diagnosis accounted for 10.6% of total admissions (percentage steadily since 1995 (Sinclair et al., 2001). No data is available on the has increased proportion to cannabis misuse. related are of admissions that proportion 2T Requests for Treatment/Counselling data current and the most reliable Reporting System (NDTRS) provides The National Drug Treatment and information on of research A bibliography for cannabis use in Ireland. on those seeking treatment is also available (O’Brien et al., 2000). The Drug Misuse issues in Ireland drug misuse and related collects data on entries into in-patient and out-patient Board Division of the Health Research Research the is taken from included here The information facilities for each of the health boards. treatment contacts aged 15-39. 1996-2000 period for treatment seek treatment Cannabis is the primary drug for which people The Le Dain Commission (Canadian Government, 1970) also highlighted the difficulties of devising a the difficulties (Canadian Government, 1970) also highlighted The Le Dain Commission with used to the breathalyser comparable body, for detecting cannabis in the human practical measure r simple method for detecting the need to develop a commission recognised and undetectable”. The It was not optimistic the body. of THC or other active cannabinoids in and concentration the presence in the immediate future. being made in this area of significant advances 72 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 2 Commission totheCounciland theEuropean ParliamentUnion ActionPlantoCombatDrugs,1999). cannabis andwere mostlikelyattributedtoharder drugs,suchasheroin (Communicationfrom the not specifyparticulardrugs,itis unlikelythatasignificantproportion ofthesecaseswere related to including witnessingdrug-related scenesorbeingavictimofviolence.Again,althoughthe authorsdo Fourteen percentofEUcitizenshaveexperiencedproblems intheircommunitiesrelating todrugs, totalled 2,600andin2000,thenumberreached over5,000. obstruction. Cannabisoffences haveincreased inboth1999and2000.In1996,cannabisoffences accounted formostdrugoffences ineveryregion, includingpossession,supply/dealing,and those intheUK(Sinclairetal.,2001;HouseofLords ReportonCannabis,2000).InIreland, cannabis possess cannabis.Cannabisoffences accountfor59%ofalldrugoffences inIreland and 64%of cannabis use.Theevidencelinkinguseandcrimeis weak, however, itisanoffence to Chapter 4containsadetaileddiscussionofthesociologicaland criminologicalimplicationsof Implications fortheNon-usingPopulation (See chapter3fordetaileddiscussionofeffects oneducationalperformanceandmotivation.) linked withsuchfactorsasanonconformistlifestyleanddelinquentsubstance-usingpeergroup. explanations, suchas“amotivationalsyndrome” (Lynskey &Hall,2000).The authorssuggestthatuseis performance, itmaybemore related tothesocialcontext ofuseratherthanpreviously cited and cannabisreveals thatalthough useisassociatedwithearlyschoolleavingandpooracademic In reference tonon-drugrelated riskfactorsassociatedwithuse,areview oneducationalattainment with illicitdrugs,alcoholdependencewasassociatedcannabisuse(Hofleretal.,1999). 2001). Eveninthecaseofexperimentalandoccasionalusers,where arelationship couldnotbefound dependence) andexperiencelegalsocialdifficulties relating totheirdrinking(Booth&Kirchner, instance, regular usersofcannabisare more likelytobediagnosedwithanalcoholdisorder (abuseor Aside from illicitdrugs,dependence onalcoholislikelytoco-occurwiththeuseofcannabis.For in detailChapter1. squamous metaplasiaoftherespiratory tract,apre-cancerous stage.Thismatterhasbeenconsidered is along-termhealthhazard, increasing thelikelihoodofdeveloping bronchitis, asthma,andeven cannabis ontherespiratory system.According totheHouseofLords Report(2000),smokingcannabis Although saferthaninjection,recent findingshavebrought toattentiontheeffects ofsmoking Risk FactorsLinkedtoCircumstances andRitualsofConsumption Context ofUse cannabis misusemayincrease therisk.Thisissueisexaminedinchapter3. a possiblenegativeoutcomethatmayresult from seriouspsychiatricdisorders anditissuggestedthat The linkbetweencannabisuseandmentalillnesshasalready beenconsidered inchapter1.Suicideis Other HealthIndicators Public HealthRisksofCannabisUse:EpidemiologicalEvidence NACD 2004 An Overview of Scientific and other Information on Cannabis 73 Public Health Risks of Cannabis Use: Epidemiological Evidence Use: Epidemiological Cannabis of Risks Health Public Chapter 2 Chapter The role of cannabis in traffic accidents in Ireland, either in combination with alcohol or alone, should accidents in Ireland, of cannabis in traffic The role be examined on an ongoing basis. There is a need to monitor cannabis use in both young people and the general population. The is a need to monitor cannabis use in both young There who have left monitoring of use among young people should include both those in school and those school early; at periodic intervals; Public attitudes and knowledge should be monitored ‘An effective public health policy is more difficult to implement when a substance is more widely used to implement when a substance is more difficult public health policy is more ‘An effective 2000); and accepted’ (Hall & Babor, to health approaches to develop credible a public health perspective is ‘The challenge from available and cannabis is widely context, where in today’s and treatment harm-reduction promotion, youth’ (Hartnoll, sections of mainstream broad contexts is seen as banal across its use in recreational 2002). ‘While occasional use does not appear to present a serious problem, cannabis dependence among a serious problem, present ‘While occasional use does not appear to et al., 2001); users is a serious public health issue’ (Poulton Cannabis use is increasing and the epidemiological evidence suggests that ‘there are a number of are and the epidemiological evidence suggests that ‘there Cannabis use is increasing ingestion that could to both acute intoxication and chronic related adverse health effects probable 2000); & Babor, (Hall a substantial public health burden’ potentially produce elatively small proportions of people consume adverse levels of the product – may lead to the conclusion – may consume adverse levels of the product of people elatively small proportions ■ ■ ■ Gaps in Knowledge attention to the following: work in an Irish context should give particular Future ■ ■ ■ A number of things are clear from the evidence presented in this review: the evidence presented clear from A number of things are ■ The purpose of this chapter was to present information to assist in answering the question – is cannabis a to assist in answering the question – is information was to present The purpose of this chapter yet somewhat inconclusive. Some facts evidence available is quite extensive and public health risk? The have tried it at least of people (a high proportion use for example its widespread about cannabis use – and that only discontinue use after their twenties often intermittent, that the majority once), that use is more r to that of other licit and illicit drugs. when compared that the public health impact is small, in particular particularly among adolescents and young is increasing, as seen above, the use of cannabis However, availability of is greater and there dose level is a difficulty adults. In addition, the complexity in establishing risky administration methods. Although the in more and an increase higher THC concentration products not as serious as other drugs, the evidence presented of cannabis use and misuse are health effects to cannabis misuse, dependence and related effects undoubtedly health-related are suggests that there of evidence that cannabis is a ‘gateway’ drug – regardless polydrug use. 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(2002).Modulationoftheeffects ofalcoholondriving-related psychomotorskills estermeyer, J.&Boedicker, A.E.(November2000).Course,severity, andtreatment ofsubstance ibberly, C.&Price,J.F. (Autumn1998).Young people’s druguse:Factsandfeelings. Public HealthRisksofCannabisUse:EpidemiologicalEvidence Children ofalcoholics. 138-142. 918-925. The InfluenceofCannabisandAlcoholonDriving. Geneva. Psychopharmacologia, 160(2), American JournalofDrugandAlcoholAbuse,26(4), Chicago: UniversityofChicagoPress. A ComparativeAppraisaloftheHealthandPsychological Science, 276, 2048-2050. Drug andAlcoholDependence, Ireland NationalReport. 213-219. Forensic ScienceInternational, T ransport Research American Journalof Journal ofChild Drug Misuse 523-535. 68, 49-62. NACD 2004 An Overview of Scientific and other Information on Cannabis 79 Mark Morgan There has also been a number of studies of chronic cannabis users from India. In general, the pattern India. In general, cannabis users from of studies of chronic has also been a number There substantial minority of people who have used among a in these has been of cognitive problems Over 30 years ago the US National Institute of Drug Abuse funded three studies in Greece, Jamaica studies in Greece, of Drug Abuse funded three Over 30 years ago the US National Institute of cannabis use. In the Jamaican study Bowman & Pihl effects and Costa Rica to examine the chronic heavy daily cannabis users who had a minimum of ten years use and on (1973) examined the effects who had no experience of in comparison to controls However, smoked an average of 23 joints a day. in either rural or urban samples. cannabis, the study failed to find any major cognitive differences inadequate.) were in this study that the controls some indications however, are (There group daily cannabis users with a control & Fink, 1977) compared study (Stefanis, Dornbush The Greek the favoured that emerged SES as well as alcohol use. The differences matched for age, gender, on verbal IQ and on specific abilities within the IQ tests. It should be noted particularly group control testing so that it is not certain that to stop use before not required that the daily users were however, of cannabis use. effects due to acute as opposed to chronic were the observed effects study but included a The Costa Rican study involved a design that was fairly similar to the Greek had been using cannabis for about 30 group follow-up study after ten years by which time the target except at the follow-up which indicated few differences 1988). The results years (Page, Fletcher & True, performed less well on tests of sustained attention and short-term group showed that the target memory. Cross-cultural Studies Cross-cultural Because cannabis has acute effects on cognitive performance, there is a major concern that its use on cognitive performance, there Because cannabis has acute effects evidence that many people who have is in cognitive impairment in the long-term. There may result solving (Stephens, Roffman of memory and in problem problems from suffer used cannabis frequently such associations should be has to do with how that emerges & Curtin, 2000). The difficulty found in these cases may have preceded that are It may be that the cognitive problems interpreted. the use of other substances. Below, from they result cannabis use or at least in some cases that studies of cannabis use and (ii) controlled studies, and as follows: (i) cross-cultural evidence is reviewed cognitive impairment. Cannabis and Cognitive Performance Cannabis and Cognitive This chapter reviews some of the major psychological consequences of cannabis use. In the first major psychological consequences of some of the This chapter reviews and controlled examined including field studies functioning are on cognitive section, the effects to particular reference on self-harm with section examines the effects laboratory work. A second of cannabis use are health. The motivational consequences of physical suicide and perception use and education outcomes chapter and the association of cannabis part of this examined in the third examined in the in the fourth section. Matters to do with occupational performance are is considered of this set out in the sixth part. The final section are fifth section while the psycho-social consequences of risk associated with cannabis use. chapter is concerned with the perception Overview Chapter Three Chapter Consequences Psychological Use of Cannabis 80 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 3 cannabis foralong timefounditharder toignore irrelevant stimuli –animpairmentthatwasnot, duration ofuse.Theresults were notfullyclear-cut. Itemerged thatthegroup whohadsmoked cannabis use.Thirtytwo userswere dividedintofour groups basedonfrequency ofuseand Solowij (1998)examinedtheextent towhichdegree ofimpairment ofattentioncouldbelinkedwith information and,specifically, tofilteroutinformationthatwasirrelevant. more errors. Theresults suggestedthatcannabisuserswere lesswellabletoprocess certainkindsof performed significantlypoorer thancontrols, withfewercorrect detections,longer reaction timesand sound inoneoftheirearsandtorespond bypressing abutton.Itemerged thatthecannabis users headphones whilebrainactivitywasrecorded. Subjectswere required toattendaparticularkindof The taskinvolvedaselectiveattentioninwhichsequences oftoneswere presented through the case. abstain from cannabisandalcohol for24hourspriortotestingandurinetestsensured thatthiswas than cannabisorhadhighlevelsofalcoholconsumption.Inaddition, thecannabisuserswere askedto Furthermore, subjectswere excludediftheyhadhistoryofpsychiatricillness,useddrugsother range ofattributesincludingage,gender, yearsof educationandpre-use estimatedIQscores. similar tothe‘experimental’group. Inanearlystudycannabisuserswere matchedwithnon-usersona A majorcharacteristicofthisworkisthecare thatSolowijhastakeninensuringcontrol groups are measures andalsobrainevent-related potential(ERP). studied theattentionprocesses ofcannabisusers,makingusebothconventionalperformance on auser’s abilitytoexcludeirrelevant stimuliwhenfocusingattentiononatest(Solowij, 1995).Solowij Among thebestknownstudiesinthisarea are thoseofSolowij,whohasexaminedlong-termeffects heavy usersdidlesswellintestsofbothmathematicalandverbalskills. standardised tests,aperiodofabstinenceatleast24hourswasrequired. Theresults showedthat usage wasdefinedasfivetimesperweekforatleastsixyears.Priortotestingonarangeof study involvedacomparisonof64lightuserscannabiswith80heavyand72controls. Heavy information collectedontheminearlyhighschool,before theybeganserioususe.Thedesignofthe importance toschoolachievement.Theresearchers matched usersandnon-usersonthebasisof the effects oflong-termcannabis useoncognitivefunctionsthatwere considered to beofmajor A studybyBlock,Farnham,Braverman,Noyes,andGhoneim(1990)inalongitudinalformatexamined affected. addition, aconsiderablefocushasbeenonidentifyingtheparticularcognitiveprocesses thatmaybe attention toensuringthatcontrol groups didnotdiffer from cannabisusersbefore theybeganuse.In Studies carriedoutoverthelast15yearshavetendedtouseWestern samplesandhavegiven alotof Controlled StudiesofCannabisUseandCognitiveImpairment compared tothecontrols againstwhomtheyhavebeen judged. users frequently differ inotherrespects likepolydruguse,poornutritionandmedicalcare certainly beenassociatedwithuse.Whatmakesthefindingsomewhatdifficult tointerpret isthatthe cognitive impairmentresulting from long-termcannabisuse.Inmanycases,suchimpairmenthas In general,itisfairtosaythatthecross-cultural studieshaveproduced equivocalevidenceof &Varma,cannabis foralongtime(Wig 1977). Psychological ConsequencesofCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 81 Psychological Consequences of Cannabis Use Cannabis of Consequences Psychological Chapter 3 Chapter emembered that while the MMSE is an appropriate measure of gross cognitive functioning, it is of gross measure is an appropriate that while the MMSE emembered the ages studied. with a decline in IQ over use was significantly related esults showed that current however, related to frequency of use. In contrast speed of information processing was related to was related information processing of use. In contrast speed of to frequency related however, examine the question of of use. The same author sought to of use but not to duration frequency the cannabis. For this study, from in ERP persisted after an extended abstinence whether the change was a partial recovery there showed that years. Her results had been abstinent for two group target of was evidence that speed there been abstinent for two years. In particular after former users had impaired. stimuli remained irrelevant ability to ignore but the improved information processing of abstinence. to length was not related occurred recovery the extent to which Furthermore, the study by Solowij and her colleagues (Solowij et al., 2002) sought to examine The most recent functioning among users who were of cognitive duration of cannabis use on specific areas of effects equal for cannabis dependence. The study involved 51 long-term users and an seeking treatment found that long-term users performed It was users as well as controls. number of shorter-term on verbal Furthermore, on tests of memory and attention. significantly less well than the other groups while the short-term users fewer items than the other groups learning tests long-term users recalled The authors conclude that long-term each other. substantially from did not differ and the controls beyond the period of endures in impairment of memory and attention that heavy cannabis use results cannabis use. intoxication and worsens with years of regular of heavy cannabis use among college (1996) examined the cognitive effects Pope and Yurgulun-Todd who had been using cannabis for at least two years on a students. Their comparison involved students The authors days monthly. than three cannabis on not more daily basis and light users who had used similar to heavy users on a range users would be more that infrequent used this design on the grounds no major demographic were students. While there of confounding variables than would control in verbal differences were on social and demographic variables, there between the groups differences was that the however, interesting What was more (SAT). Scholastic Aptitude Tests IQ and self-reported memory scale and the Weschler processing on tests of digit span, auditory sequential differed groups these significantly, attention. More measure specifically designed to as well as on tests that were IQ and self-reported in Verbal made for the differences persisted when adjustments were differences of cannabis on memory and attention. indicating effects scores, test SAT The study some of the most convincing evidence in this area. longitudinal studies provide The recent use on cognitive of cannabis Liang and Anthony (1999) examined the effects Garret, by Lyketsos, than 11 years after they had been assessed using the Mini functioning among over 1300 adults more among participants taken together declined by 1.2 Mental State Examination (MMSE). The scores was however, points over the 11 years and this decline was highest among older participants. There and this lack of a relationship in cognitive score between cannabis use and decline no relationship applied for age, gender and use of other drugs. It should be were persisted even when controls r to above as in the work of Solowij. referred that were of the subtle impairments not a measure of cannabis on IQ is also worth noting. The recent longitudinal study of the effects Another recent in the early teens (10-12 years) James and Gray (2002), examined IQ scores study by Fried, Watkinson, use. The of cannabis with frequency the changed scores with those age 18-20 years and compared r former to gains for light users, of 4.1 points in heavy users compared was an average decrease There users and non-users. 82 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 3 indications thatinmanycasestheimpairmentcanbereversed withaprolonged periodofabstinence. impairments ofmemory, attentionandtheorganisation ofcomplexinformation.Thirdly there are However, there isaconsiderablebodyofevidencethatheavycannabisuseproduces subtlecognitive something whichmayrelate tothefailure tofindgross structuralchangesinthebrainsofusers. Firstly, there islittle evidencethatcannabisproduces severe impairment ofbroad cognitivefunctions, A numberofconclusionsare appropriate regarding theeffects ofcannabisoncognitivefunctioning. in thisstudy)were notsignificant. r Creative BehaviourInventory togetherwithmeasures ofsubstanceuse.Thefindingsindicatedthatthe motivational dimensions.OnestudythatexaminedthiswasbyPlucker&Dana(1998)whousedthe functioning wouldbeinthedomainofcreativity andaspectsofcognitionthatinterfacewithpersonal- may havebeneficialeffects on certainformsofcognitivefunctioning.Themostlikelyfeatures of Only asmallamountofresearch attentionseemstohave been giventotheideathatcannabisuse this time. cognitive effects. Thereason forthedifference betweenthestudiesbyPopeandBollaisnotclearat also emerged thatduration of cannabisusehadlittleinfluenceonthepersistencenegative measures used(includingmemory, psychomotorspeedandmanualdexterity),evenafterabstinence.It persisted after28days.Agroup ofheavycannabisusersshowedpoorer performanceinfiveof35 On theotherhand,Bolla,Brown, Eldreth, Tate &Cadet(2002)foundthatdecrements inperformance differences betweenthethree groups ontheperformanceofvarioustasks. memory tasksbefore andupto7daysabstinence.By28however, there were virtuallyno verbal fluencyandsustainedattention.Current heavyusersscored significantlybelowcontrols on and 28daysofabstinencefrom use.Thetestbatteryincludedmeasures ofintellectualfunctioning, tests togroups ofcurrent heavyusersofcannabis,formerandnormalcontrols after1,7, cannabis. AstudybyPope,Gruber, Hudson,Huestis&Yurgelun-Todd (2001)administered abatteryof One interesting pointthatemerges inanumberofstudies concernsthereversibility oftheeffects of domains suchasmemoryandattention. cannabis doesnothaveamajoreffect onglobalintelligence,there mightbeaneffect incognitive previously beenheavyusersbutwhonolongerusedthesubstance.Theyalsoconcludedthatwhile smoked 5jointsaweekormore. Anegativeeffect wasnotobservedamongpeoplewhohad The authorsconcludedthatheavyusehadanegativeeffect onglobalIQscores onlyifthesubjects cannabis andsuicide attemptsremained significant evenwhensocio-demographic factors,other well asinhalants,alcoholandsedatives. Whatwasinteresting however, isthattheassociationbetween between self-reported suicideattemptsanddependenceon anumberofdrugsincludingcannabisas W deciding whethertherelationship iscausalorcanbeexplained byotherfactors.ThestudyBorges, In decidingabouttherelationship betweencannabisuseandsuicide,oneofthemajorproblems isin Cannabis andSuicide Cannabis andSelf-injuriousBehaviour elationship betweenvariousformsofsubstanceuse,includingcannabis,andcreativity (asmeasured alters andKessler(2000)inacross-sectional studyfocusing on‘co-morbidity’foundanassociation Psychological ConsequencesofCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 83 Psychological Consequences of Cannabis Use Cannabis of Consequences Psychological Chapter 3 Chapter egression analysis showed that emotional well-being predicted most of the variance in suicidal analysis showed that emotional well-being predicted egression psychiatric disorders and alcohol dependence were controlled. The odds ratio was 2.4 indicating that The odds ratio was 2.4 indicating controlled. dependence were and alcohol psychiatric disorders such attempts than report likely to times more between two and three were those using cannabis cannabis use. people not reporting suicide of serious hospitals as a result (1999) looked at cases admitted to Beautrais, Joyce & Mulder over 300 cases admitted to hospital with of their study involved a comparison of attempts. The design about were that the hospital group This comparison indicated randomly. over 1000 people selected for social likely to have had a heavy involvement in cannabis use. Controlling eight times more the association substantially but the odds reduced disadvantage and having a history of depression at 2.00. ratio still remained was concerned with factors associated with suicidal The study by Field, Diego & Sanders (2001) in a number found to differ suicidal ideation were ideation. Those high school seniors who reported family relationships, those who did not on a number of variables including family, of ways from that a emotional well-being and substance use, including cannabis use. It is interesting depression, r use, added a modest level to the extent of the variance ideation while other factors, including drug explained. of risk-taking, which in to other forms use is related A number of studies have shown that cannabis Felts, Chenier & Parrillo (1995) found that A study by Burge, behaviour. to self-injurious related turn are sexual activity and to a range of high risk behaviours including precocious substance use was related use was especially strongly that in this study cocaine suicidal ideation. It was particularly interesting somewhat were attempts while the relationships associated with severity of outcomes of suicide use. weaker in the case of alcohol and cannabis drinking, cannabis between found a relationship A study by Rodondi, Narring & Michaud (2000) it young people in Switzerland. However, suicide in a sample of 2,500 use and having considered of cannabis and and the relationship strong was not especially should be noted that the relationship than was the case with having thought alcohol use with other risky behaviours was much stronger about suicide. indications that in cases of suicide, cannabis use is often strong are One important point is that there Rich, Ghani & found to be associated with other forms of substance misuse. A study by Dhossche, for over 300 suicides in Alabama, USA. Isacsson (2001) examined postmortem toxicology records categories: (i) alcohol, cocaine and cannabis; broad into three grouped Psycho-active substances were medications. What was most psycho-tropic medications; and (iii) non-abused (ii) abusable prescription of cases than two third between the various categories. In more was the extent of overlap interesting was also evidence of the abuse of an found to be used, there cannabis and alcohol were where abusable medication. 84 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 3 development ofsuchascalefor peopleintreatment foravariety ofaddictionsincludingcannabis component ofmotivation).One studyalongtheselines(Sklar&Turner, 1999)wasconcernedwith judgments are powerfulpredictors ofreadiness totackle andcopewithparticulartasks(anessential There issomeinterest in the associationbetweencannabisuseandself-efficacy judgmentssincesuch motivation isparticularlyassociatedwithcannabisuse. environment wasstableandpredictable. There islittleevidenceinthesefindingsthatlackof another byahighlevelofunhappiness,andthird andlargest group whobelievedthattheir cluster analysis.Three groups emerged, oneofwhichwascharacterisedbyanti-socialbehaviour, examined theprofile ofstudents whohadusedcannabisatleast40timesintheirlives,basedona The studybyMiller&Plant(2002)wasbasedondatafrom studentsintheUKESPAD study. They r frequently were somewhatlessanxiousandemotionally-stressed thantheothergroups. These barbiturates) witheachgroup completingapersonalityinventory. Thosewhotendedtousecannabis Gorman (1975)examinedthree groups ofcollegedrugusers (cannabis,amphetaminesand personality andmotivationalcharacteristicsofusersnon-users.Forexample,Crain,Ertel& One typeofstudythatwastraditionallyverypopularadesigninvolvedlookingatthe may haveexistedinadditiontoandpriorcannabisuse. whether thecontrols thatwere appliedwere sufficient toruleoutother(psychological)differences that being lesslikelytohavebeenpromoted andbeingmore likelytobeindebt.However, itisnotclear users suffered from avarietyofnegativeeffects includinghavingalessgoodemploymentrecord, matched onrelevant characteristics likeage,educationandoccupation.Theresults indicatedthatthe In anearlystudy, Carteretal.(1980)compared 41heavyuserswithasimilarnumberofnon-users to findclear-cut evidenceforthissyndrome. considered tobesuffering from an‘amotivationalsyndrome’. Subsequentstudieshowever, havefailed US were considered bymanypeopletobesoapathetic,lethargic andunmotivatedthattheywere Over 30yearsago,itemerged thatchronic cannabisusers inJamaica,Egypt,theCaribbeanand Motivational ConsequencesofCannabisUse well beanimportantinfluencewhentherelationship betweenhealthandcannabisuseisconsidered. physical activitywasrelatively loweramongstudentswhowere frequent cannabisusers. Thismight (1995)ofAmericanHighSchoolstudentsfoundthat It isalsoofinterest thatastudybyWinnail academic achievementandself-esteemaswelldemographicfactors. difference tosuchratingsinastudyofstudentsthatincluded othervariableslikefinancialsituation, Wadesuch ratings,Vingilis, &Adlaf(1998)foundthatcannabisusewasoneofthefactorsmadea negatively related toperception ofone’s ownstateofphysicalhealth.Inastudyfactorsinfluencing of howdepression isaffected bycannabisuse.Theevidencesuggeststhatregular cannabisuseis r topic thatisgivenconsiderationinchapters1and2.However, itisinteresting toconsiderthe It isbeyondthescopeofpresent chaptertoconsidertheeffects ofcannabisonphysicalhealth–a Cannabis andPerception ofPhysicalHealth esults mayhavesomeimplicationsformotivationespeciallythe lowerlevelsofanxiety. elationship betweencannabisuseandperceptions andratingofhealth,sincethislinkswiththeissue Psychological ConsequencesofCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 85 Psychological Consequences of Cannabis Use Cannabis of Consequences Psychological Chapter 3 Chapter ecco and Pelc (2002) notes that in a small number of studies it has been found that cannabis can ecco and Pelc (2002) notes that in a small Cannabis Use and Educational Outcomes studies (in Ireland In line with the view that bonding to school is weaker among cannabis users, several with poor school performance including have shown that cannabis use is associated and abroad) & Lynskey 1986; Fergusson, (Grube & Morgan, out grades, attendance and likelihood of dropping are of cannabis use, a number of interpretations Horwood, 1995). As in the case of many correlates performance. possible. It may indeed be the case that cannabis use is a causal factor in poor school both cannabis and poor school that common factors influence Equally it could be argued performance. between cannabis use and factors associated of the association What is very striking is the strength use on with academic success. Sanders, Field and Diego (2001) studied the influence of substance has been Ireland, academic expectations (which in several studies, including a number carried out in substance use with achievement, Kellaghan et al., 1995). Interestingly associated shown to be strongly than half of the total variance in predicting (particularly cannabis and cocaine use) accounted for more academic expectations. addiction. While they have produced a scale with good reliability and validity in assessing self-efficacy and validity in a scale with good reliability have produced addiction. While they to the regard limits its value with group the absence of a suitable control in high-risk situations, of cannabis. effects question of motivational on a appear in the literature of cannabis on motivation continue to the effects Laboratory studies of of cannabis checked the effects Lane & Dougherty (2002) study by Cherek, basis. A recent fairly regular They found that the progressively. decreased expended when the amount to be earned use on effort in time spent and in money in the number of responses, reductions in potency-related drug resulted as ‘amotivational’. that they interpret earned – effects may be a factor in using cannabis (rather than the other The possibility that certain styles of motivation et al., (2002) was study by Wulfert has been raised in a number of studies. A recent way round) a choice is adolescents. As is typical in this kind of study, concerned with delay of gratification among one, some time later. which can be obtained immediately and a larger given between a small reward delay gratification is a major factor in motivation for It is generally thought that this capacity to work, it is the perspective of the present From long-term goals like obtaining a college degree. likely to occur among more et al. study found that certain behaviours were that the Wulfert interesting gratification). These included a greater (did not delay adolescents who choose an immediate reward Thus it could be the case that and cannabis in particular. involvement with substance use generally associated with which in turn are motivational styles cannabis use is associated with different associated with loss of motivation. subsequent outcomes that are have positive some studies that indicate that cannabis can in some circumstances are there Finally, by Hanak, sustained period. The review physical work over a working, especially with hard on effects T Jamaica by Rubin notably a study of Ganja use in productivity, alleviate fatigue and thus increase by Nahas (1985) shows important a critique of this latter study and Comitas (1975). However, motivational methodological flaws and concludes that the acceptance by the authors of positive than on objective evidence. on philosophical premises is based more effects 86 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 3 r are likelytofindthemselvesbereft ofanyformfurthereducation,thuscontributingto the cannabis, alcoholandotherdrugs. Itisalsoofinterest tonote thatstudentssuspendedfrom school doubled. Thosewhowere suspendedorexpelledwere muchmore likelythantheirpeerstouse Ziedenberg (2001)showedthatoverthelast20yearsnumber ofexpulsionsfrom USschools had suspensions/expulsions from school.Areview ofthepatternandcausesexpulsionby Shiraldi& One interesting pointemerging inrecent research isthatcannabisuseinvolved inalarge numberof expectation ofgoingtocollegewere controlled. r dropping outofschool,failure tograduatefrom college,aswellunemployment.However, this employment status.Asmightbeexpectedthere wasasubstantialrelationship betweendruguseand was completed,progress tocollegeandcompletionofcollege,aswelloccupationalstatus were assessedatage25-30years. Amongtheoutcomesthatwere assessedwere whether highschool cannabis andotherdruguseatage14-17yearsonavarietyof educationalandotheroutcomeswhich In anotherAmericanstudy, Tanner, Davies&O’Grady(1999)lookedattherelationship between adolescent supervisionandcannabisuseemerged asmajorpredictors ofdrop-out. pattern ofresults were somewhatdifferent formalesandfemales.However, forallyoungpeople and performance,aggressiveness, aswelladolescentcannabisuse.Itisinteresting thatthe adolescent influencesonlaterschooldrop-out. Theseincludedsocialbackground, schoolbehaviour Another highqualitystudybyEnsminger, Lamkin& Jacobsen(1996)studiedarangeofchildand substance persebutontheassociatedunconventionallifestyle. an importantconsiderationsincemanycriticismsofcannabisusefocusnotonthe unconventional butwhere there were nodeepfeelingsofadherence tothatunconventionality. Thisis out, thiswasmore likelytohappen whenitoccurred inthecontextofalifestylethatwas Thus, whileinthisandseveralotherstudies,cannabisusewasfoundtobeassociatedwithdropping as muchtheextenttowhichfamiliesadhered tovaluesaround thatlifestyle. associated withstrong belief inlifestylevalues.Inotherwords, thecriticalfactorwasnotlifestyle, the probability ofdropping out,thiswasnotthecasewhere thenon-conventionallifestyle was associated withdrugusebyparents, couldleadtocannabisusebychildren, whichinturnincreased What wasparticularlyinteresting isthatwhilenon-conventionallifestyles,whichwere sometimes orientation towards immediate gratification,anti-authorityandnon-materialisticorientation. values/family structures were measured through alternativeachievementgoals,self-reliant lifestyles, conventional familystructures andvaluesininteractionwithothervariables.Non-conventional longitudinal study. Whatwasespeciallyinteresting isthatthisstudyexaminedtheeffects ofnon- examined awholerangeofchildandfamilyvariablesindropping outofhighschool,ina19-year One ofthebest-controlled studiesisanAmericanstudybyGarnier, Stein&Jacobs(1997),which generally, were likelytoabandonacollegeeducation. educational disadvantage),theyfoundthatcannabisusersspecifically, andsubstanceusersmore years. Evenwhentheyhadtakenaccountofavarietyfactorsthataffect leavingcollege(including school studentsover8yearstoassesstheimpactofearlydruguseoneducationaloutcomeatage19 studies offer thebestprospect ofresolving thisissue.Newcomb&Bentler(1988)followedUShigh However, evenaverystrong associationdoesnotofitselfensure acausalrelationship. Longitudinal elationship between pooreducationalachievement andcannabisuse. elationship (thoughdiminished)stillpersistedevenaftersocial background, cognitivecapacity, and Psychological ConsequencesofCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 87 Psychological Consequences of Cannabis Use Cannabis of Consequences Psychological Chapter 3 Chapter elating to the association between school performance and cannabis use. elationship is almost certainly due to other factors, it is noteworthy that the association still remains elationship is almost certainly due to other Cannabis Use and Occupational Performance to do with motivation or because of for reasons it might be expected that For people in the workforce might be expected to do less well at work than those not using the cannabis users cognitive effects, to take into account the findings discussed above has any finding in this area substance. However, r between A well-known study by Mensch & Kandel (1988) sought to establish the relationship was only a modest relationship showed that there occupational status and substance use. Their results smoking. Generally between substance use and occupational status, except in the case of cigarette it job satisfaction and cannabis use. However, between only weak correlations were speaking there somewhat more lacking in variety and complexity were that people in occupations that were emerged in nature that this study is cross-sectional likely to smoke cannabis during work. It should be stressed is impossible to untangle. the matter of cause and effect and therefore convincing evidence on the relationship more On the other hand some longitudinal studies offer adolescents between employment and cannabis use. A study by Newcomb & Bentler (1988) followed for educational also able to control and were high school into employment and young adulthood from characteristics which may have been associated with cannabis use. They found and other differences and lower job job instability, likely to have a lower income, greater more that cannabis users were Conclusions Regarding Cannabis Use and Educational Outcomes Cannabis Conclusions Regarding poor educational outcomes, and especially early school The association between cannabis use and While some of the and most consistent in the international literature. leaving, is one of the strongest r expectations and parental background applied to a range of factors like social are even when controls and supervision. some indications are is mediated. As noted above there as to how the effect The question still remains this comes about only after cognitive capacity (IQ and similar tests) but that that cannabis can affect whose usage. It is doubtful if any of the studies included many young people intense and prolonged cognitive skills. Another factor might be motivation and the level of use was such as to damage their which on motivational processes, use of cannabis of prolonged evidence on the damaging effects motivation what has been demonstrated about cannabis in school. However, might include interest which low levels of use is unlikely to apply to the relatively again applies only to very heavy users and school drop-out. has been shown to be associated with early The recent study by Brook, Adams, Balka, & Johnson (2002) was concerned with the relationship & Johnson (2002) was concerned with Adams, Balka, study by Brook, The recent samples of among two large use and educational and other variables, between early cannabis a range of variables associated with in the US. This longitudinal study included disadvantaged youth The results these to cannabis use five years earlier. and sought to relate transition to young adulthood educational and occupational use was associated with having lower indicated that early cannabis of rebelliousness. school, as well some indicators or expelled from expectations, being suspended ethnicity and maternal gender, variables including on relevant controls with These findings emerged education. 88 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 3 significant. This ispartlyduetothelarge number ofrespondents intheESPAD study(over2,300for forms ofanti-socialbehaviourand thethree formsofsubstance useconsidered are statistically A numberofinteresting pointsemerge from Table 5.Firstly, allofthecorrelations betweenthevarious with smokingandrecent alcoholuseisalsoshown. social behaviourintheESPAD 1999study(Hibelletal., 2001).To assistininterpretation theassociation T with violenceismediatedthrough usersearlyandactiveinvolvementintheillegaldrugsmarket. either alcoholuseormentalillness.Onesuggestionthatemerges inthisstudyisthatthe association risk ofbecomingaviolentoffender couldbeattributedtocannabisuse.Thiswasmuchstronger than even whencontrols were appliedfordemographicfactorsandotherdisorders, about28%ofthe cannabis useonviolentbehaviouratage21yearsinaNewZealand cohort.Theresults indicated that behaviour andcannabisuse.Intheinternationalliterature Arsenault(2000)examinedtheeffect of it isofinterest tonotethatseveral surveyshaveshownarelationship betweenreports of anti-social The issueoftherelationship betweencriminalityandcannabisuseisconsidered inchapter4.However Cannabis UseandAnti-socialBehaviour and bondingtoreligion has alsobeenconsistentlyfound(e.g.,Grube&Morgan, 1986). cannabis use(Lynskey &Hall,2000).Theevidence onanegativerelationship betweencannabisuse school. Infactinmanystudiestruancyfrom schoolisoneofthestrongest predictors ofregular Specifically, there isevidencefrom severalstudiesthatcannabisusersare lesslikelytobebonded engaging infamilyorchurch activities. the timeoreffort oneexpends withinthecontextofagivenrelationship orsocialinstitutione.g. r institution likeschoolorChurch. Commitmentrefers totheextentwhichanindividualbelieves commitment andinvolvement.Attachmentrefers totheeffective bondsbetweenanindividualand who usecannabis.Socialbondingisconceptualisedasconsistingofthree processes: attachment, Similarly there wasevidence from thesamestudyofrelatively lessersocialbonding by youngpeople teachers/parents, damagedproperty andstolenthings. more likelytobeinvolvedin arangeofbehavioursthatincludedhavingswornorcursed,liedto Grube &Morgan (1986)whofoundthatthoseadolescentshadusedcannabiswere somewhat frequently regarded asdeviant.OneofthefirststudiesinIreland toillustratethispointwasthatof It isevidentthatuseofcannabisassociatedwitharangebehaviours,beliefsandattitudesare Psycho-social ConsequencesofCannabisUse background andschoolperformance,theassociationdeclinedbutstillremained substantial. had beenregular cannabisusersatage16years.Whencontrols were appliedforco-variateslikesocial (1997). Thisstudyshowedthattherateofunemploymentwasaboutfourtimesgreater for those who One ofthemore substantialrecent findingsinthisarea isfoundintheworkofFergusson &Horwood conscientious, thorough andreliable. satisfaction. Theyhavespeculatedthatthisdifference maybeduetocannabisuserstendingless elationship withanotherisimportantorvaluesaninstitutionitsgoals.Finally, involvementrefers to able 5showstheassociationforIrish16-yearoldsbetweencannabis useandvariousformsofanti- Psychological ConsequencesofCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 89 Psychological Consequences of Cannabis Use Cannabis of Consequences Psychological Chapter 3 Chapter Cigarette Smoking*Cigarette Alcohol** Cannabis use*** 12) .23 .25 .31 € Stole something (>about into a place to steal Broken Damaged propertySold stolen goods .18 .21 .19 .19 .28 .22 .22 .39 .29 BullyingHurting someoneStarting a fight (another group)Starting a fight (individual) .26 .17 .20 .12 .31 .22 .28 .15 .30 .27 .23 .16 able 5. ESPAD (1999): Association of Cannabis, Cigarette and Alcohol Use with (1999): Association of Cannabis, Cigarette able 5. ESPAD Cannabis Use and Victimisation be a It has often been suggested that factors that influence anti-social behaviour may also countries in a number of to being a victim of a crime. For these reasons contributory factor with regard parallel to to victimisation that were included items with regard study including Ireland the ESPAD those for anti-social behaviour. is a pattern of generally weak, but positive, 6 (page 90) that there Table It can be seen from it between substance use, including cannabis, and various forms of victimisation. However, correlations as is the case with the parallel forms of anti- not as strong are is also noteworthy that the correlations is a slight and alcohol), there (cigarettes Comparing cannabis with other substances social behaviour. This was not nearly on average. with victimisation to be slightly greater tendency for the correlations as in the case of anti-social behaviour. as pronounced T Anti-social Behaviour Ireland). In general the correlations are in the middle range rather than being high or low, indicating range rather than being high or low, in the middle are In general the correlations Ireland). different not very are point is that the correlations Another interesting moderate level of association. violence. e.g. stealing vs. behaviour, for various forms of anti-social consideration is that the correlation the most important study, perspective of the present the From is the case with cigarette than and anti-social behaviour is generally stronger between cannabis use behaviour with the exception This is the case for the various forms of anti-social smoking or drinking. association with stronger was a relatively there behaviour, of ‘starting a fight’. In the case of the latter to smoking or cannabis use – something that seems alcohol consumption than with either cigarette make sense. * Measured as the number of cigarettes smoked daily in the previous month smoked daily in the previous as the number of cigarettes * Measured month in the previous as the number of times alcohol was consumed ** Measured year times cannabis was used in the previous as the number of *** Measured statistically significant shown above are Note: All of the correlations 90 An Overview of Scientific and other Information on Cannabis NACD 2004 Note: Allofthecorrelations shownaboveare statisticallysignificant *** Measured asthenumberoftimescannabiswasusedinprevious year ** Measured asthenumber of timesalcoholwasconsumedintheprevious month * Measured asthenumberofcigarettes smokeddailyinthe previous month ns –notsignificant Chapter 3 case ofoccasional cannabisisquitemodestin mostcountries.InIreland for example,lessthanone A numberofinteresting pointsemerge from Table 7.Firstly, theoveralllevelofriskperceived inthe heavy smokingandbingedrinking. information foranumberofNorthern European countriesand includes,forcomparisonpurposes, frequent useofcannabisaswellforavarietyothersubstances. Table 7summarisesthis particularly interesting abouttheESPAD questionisthatitaskedaboutthedangerofoccasionaland perceived dangersofvarious kindsofsubstanceuseamong16-yearoldsinEurope. Whatwas The samegeneralpointemerges intheESPAD studyin1995and1999whichinquired aboutthe consequences. use hadmajornegativeconsequenceseitherintermsofgetting caught,ornegativesocialhealth in NewZealandwhethernonusers,occasionalorheavyusersof cannabisdidnotthinkthat study byPoulton,Moffitt, Harrington,Milne&Caspi(2001)showedthatyoungpeopleintheir twenties What isclearthatmanyyoungpeopledonotseecannabis use asbeingdangerous. Forexample,a unlikely tobesuccessful. several yearsfrom now. Theresult isthatmanycurrent approaches thatare basedoninformationare that theirbehaviourmayresult inearlyschoolleaving,losingmotivationorbecomingdepressed considered thisissueandtheydrawattentiontothedifficulty ofgettingadolescentstounderstand the risksthatmayoccurseveralyearslater. Inarecent publication,Gruber&Pope(2002)have several years.Theproblem isthatmanyadolescentshavegreat difficulty inmakingdecisionsabout extreme. Furthermore, asshownabove,manyoftheadverse long-termeffects applytoheavyuseover One ofthechallengesforprevention isthattheimmediateadverseeffects ofcannabisare not Perceptions oftheRisksCannabisUse Vi T able 6.ESPAD (1999):AssociationofCannabis,Cigarette andAlcoholUsewith a ypoet aae sn ns .28 .16 ns ns .17 ns .16 ns .28 ns ns .17 ns .14 .19 .12 ns ns Had myproperty stolenorsold .16 .21 Had myproperty damaged Had myhousebroken intoforstealing Had somethingstolen(about Being victimofafight(individual) Being victimofafight(group) Being hurt Being bullied ctimisation Psychological ConsequencesofCannabisUse € 2 1 1 .12 .10 .18 12) iaet mkn*Achl*CannabisUse*** Alcohol** Cigarette Smoking* NACD 2004 An Overview of Scientific and other Information on Cannabis 91 Psychological Consequences of Cannabis Use Cannabis of Consequences Psychological Chapter 3 Chapter Heavy Binge Occasional Regular Smoking Drinking Cannabis Cannabis verage (All) 65 38 43 78 A FranceIrelandUKSweden 71 67 69 62 60 18 44 17 21 32 44 23 60 63 89 56 Denmark 70 17 24 74 able 7. ESPAD (1999): Perceived Risk of Substance Use (1999): Perceived able 7. ESPAD egular use. However, it should also be noted that in general the Irish sample perceived relatively less relatively noted that in general the Irish sample perceived it should also be egular use. However, cannabis use regular words the same as for heavy smoking. In other egular cannabis use was roughly Conclusions associations of cannabis use with a variety of outcomes and consequently the strong are There is a considerable body of evidence that heavy cannabis use there However, is difficult. interpretation of complex attention and the organisation subtle cognitive impairments of memory, produces information. and unmotivated. It has often been suggested that cannabis users appear to be apathetic, lethargic a variety of negative from studies, cannabis users suffered shows that even in controlled The research and being being less likely to gain promotion employment record, including having a poorer effects sufficient applied are that are it is not clear whether the controls likely to be in debt. However, more that may have existed in addition to and prior to cannabis use. to rule out other differences educational outcomes, and especially early association between cannabis use and poor A strong on the consequences of school leaving is one of the best-established findings in the literature cannabis use. T third of the sample of 16-year olds took the view that occasional cannabis use was a great risk. On the occasional cannabis use was a great sample of 16-year olds took the view that of the third most countries about risk. In use was a greater cannabis view was that regular other hand, the general to ‘occasional’ use. risk compared was a great people thought that ‘regular’ twice as many young to the use compared risk in cannabis see great is that fewer Irish 16-year olds Another point emerging occasional and the case for the UK). This is true for both average (the same is broadly European r was a of heavy smoking. It is important to note that there risk for all substance use with the exception risk of a substance and actual use of that substance. between the level of perceived correlation strong risk attached to 7 is that for Irish adolescents, the perceived Table from A final point that emerges r This is an interesting smoking of cigarettes. as regular was thought to have about the same risk of cannabis use. the effects regarding review of the present outcome given the results Note: Table entries are percentages of students in each country who thought the behaviour in percentages entries are Note: Table countries shown is for all 29 ESPAD average figure risk’. The question was a ‘great 92 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 3 ■ ■ ■ ■ Future workshould: the Irishcontext. As intheotherchapters,attentionwillbefocusedongapsknowledgethatare especiallyrelevant in Gaps inKnowledge due inparttoothersubstances,bothlegalandillegal,beingfoundthesecasesalso. heavy cannabisusethanare others.However, theprecise role ofcannabisperseishard topinpoint There isconsistentevidencethatyoungpeopleattemptingsuicideare more likelytohaveahistoryof school were foundtobemuchmore likelythantheirpeers tousecannabis,alcoholandotherdrugs. One importantpointemerging inrecent research isthatthosewhowere suspendedorexpelledfrom Examine existingschoolpoliciesandpracticeswithregard tocannabis; early schoolleavingandeducationaloutcomesinIreland; The needtolookatcannabisuseinstudiesofeducationalachievementasonethefactors cannabis use; Establish theextenttowhichthere isarelationship betweenphysicalhealth,wellbeingand Investigate relationships between cannabisuseandsuicides,self-injuriousbehaviour; Psychological ConsequencesofCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 93 781-789. 26-38. Journal of Affective New Zealand Journal Psychopharmacologia, 29, Psychological Consequences of Cannabis Use Cannabis of Consequences Psychological 79-91. 2400-2416. 849-856. 65, 222- 227. Chapter 3 Chapter American Journal of Epidemiology, 151, American Journal of Epidemiology, Cannabis in Costa Rica: A study of chronic marijuana use. Cannabis in Costa Rica: A study of chronic Experimental Clinical Psychopharmacology, 10, Experimental Clinical Psychopharmacology, 57, 979-986. 96-111. Child Development, 67, Psychological Medicine, 32, 1337-1343. Journal of School Health, 30, 25-38. International Journal of Addictions, 10, Neurology, 59, Neurology, 1155- 1164. 64, 167-174. NIDA Research monograph, NIDA Research Archives of General Psychiatry, Archives Carter, W., Coggins, W. & Doughty, P. (1980). P. & Doughty, Coggins, W. W., Carter, Philadelphia: Institute for the Study of Human Issues. following marijuana D. M. (2002). Possible amotivational effects D. R., Lane, S. D. & Dougherty, Cherek, smoking under laboratory conditions. Crain, W. C., Ertel, D. & Gorman, B. S. (1975). Personality correlates of drug preference among college of drug preference C., Ertel, D. & Gorman, B. S. (1975). Personality correlates Crain, W. undergraduates. Beautrais, A. L., Joyce, P. R. & Mulder, R. T. (1999). Cannabis abuse and serious suicide attempts. (1999). Cannabis R. T. R. & Mulder, P. Beautrais, A. L., Joyce, Addiction, 94, R. & Ghoneim, M.M. (1990). Long-term marijuana use Block, R. I., Farnham, S., Braverman, K., Noyes, to school achievement: Preliminary on learning and cognitive functions related and subsequent effects study. of effects neuro-cognitive Dose-related K. & Cadet, J.L. (2002). D., Tate, K., Eldreth, Bolla, K. I., Brown, marijuana use. Borges, G., Walters, E. E., & Kessler, R. C. (2000). Associations of substance use, abuse and R. C. (2000). Associations of substance use, abuse & Kessler, E. E., G., Walters, Borges, dependence with subsequent suicidal behaviour. Arsenault, L. (2000). Mental disorders and violence in a total birth cohort: Results from the Dunedin Results from and violence in a total birth cohort: disorders Arsenault, L. (2000). Mental study. References Bowman, M. & Pihl, R. (1973). Cannabis: Psychological effects of chronic heavy use: a controlled heavy use: a controlled of chronic effects Bowman, M. & Pihl, R. (1973). Cannabis: Psychological users of high-potency cannabis. study of intellectual functioning in chronic 159-170. marijuana use: risk for the J. S., Adams, R. E., Balka, E. B. & Johnson, E. (2002). Early adolescent Brook, transition to young adulthood. (1995). Drug use, sexual activity and suicidal behaviour A. V. & Parrillo, T. Felts, M., Chenier, V., Burge, in US high school students. Dhossche, D. M., Rich, C. L., Ghani, S. O. & Isacsson, G. (2001). Patterns of psycho-active substance Dhossche, D. M., Rich, C. L., Ghani, S. O. & Isacsson, G. (2001). Patterns of psycho-active toxicology in suicides in Alabama between 1990 and 1998. routine detection from Disorders, & Jacobsen, N. (1996). School leaving: A longitudinal perspective M. E., Lamkin, R. P. Ensminger, including neighbourhood effects. of Educational Studies, Fergusson, D. M., Lynskey, M. T. & Horwood, L. J. (1995). Truancy in adolescence. in adolescence. & Horwood, L. J. (1995). Truancy M. T. D. M., Lynskey, Fergusson, 94 An Overview of Scientific and other Information on Cannabis NACD 2004 perspective. Garnier, H.E.,Stein,G.A.&Jacobs,J.K.(1997).Theprocess ofdropping outofhighschool:A19-year Journal, 166, findings ofalongitudinalstudyeffects onIQinyoungadults. Fried, P., Watkinson, B.,James,D.&Gray, R.(2002).Current andformermarijuanause:Preliminary Field, T., Diego,M.&Sanders,C.(2001).Adolescentsuicidalideation. Chapter 3 young adults. Fergusson, D.M.&Horwood,L.J.(1997).Earlyonsetofcannabisuseandpsycho-socialadjustment in The CostaRicanfollow-up. Page, J.,Fletcher, J.&True, W. (1988).Psychosociocultural perspectivesonchronic cannabis use: Sage Publications. Newcomb, M.D.&Bentler, P. (1988). Nahas, G.(1985).CritiqueofastudyongangainJamaica. Alcohol Dependence, Miller, P. &Plant,M.(2002).Heavycannabisusers amongUKteenagers:Anexploration. Education, Mensch, B.S.&Kandel,D.(1988).Dropping outofhighschoolanddruginvolvement. persons under65yearsofage. L Dublin: EducationalResearch Centre. Kellaghan, T., Weir, S., O hUallachain,S.&Morgan, M.(1995). Stockholm: CAN. The 1999ESPAD report: Alcoholandotherdruguseamongstudentsin30European countries. Hibell, B.,Andersson,Alstrom, S.,Balakireva, O.,Bjarnasson, T., Kokkevi,A.&Morgan, M.(2001). Scientific Conference onCannabis: Hanak, C.,Tecco, J.&Pelc,I.(2002). North America, Gruber, A.J.&Pope,H.G.(2002).Marijuanauseamong adolescents. school pupils. Grube, J.W. &Morgan, M.(1986). A review. L yketsos, C.G.,Garret, E.,Liang,K.Y. &Anthony, J.C.(1999).Cannabisuseandcognitivedeclinein ynskey, M.,Hall,W. (2000).Theeffects ofadolescentcannabisuseoneducationalattainment: Addiction Psychological ConsequencesofCannabisUse 61, 95-113. American EducationalResearch Journal, 887-891. Addiction, Dublin: ESRIGeneralPublications. 49, 389-413. Nov; 95(11),1621-30. 65, 235-242. 92, 279-296. Journal ofPsychoactiveDrugs,20, American JournalofEpidemiology, 149, Smoking, drinkingandotherdruguseamongDublinpost-primary Brussels: MinistryofPublicHealthBelgium. Cannabis, mentalhealthanddependence.InInternational Consequences ofadolescentdruguse.California: 34, 395-419. Bulletin onNarcotics, Educational disadvantageinIreland. 57-65. Canadian MedicalAssociation Pediatric andClinicalJournalof Adolescence, 794-800. 37, 15-29. 142, 241-248. Drug and Sociology of NACD 2004 An Overview of Scientific and other Information on Cannabis 95 New 250-274. New York: Raven Press. New York: 472-483. 521- 527. 602-607. Archives of General Psychiatry, of General Psychiatry, Archives Psychological Consequences of Cannabis Use Cannabis of Consequences Psychological 898-908. Social Problems, 46, Social Problems, Cambridge: Cambridge University Press. Chapter 3 Chapter 1123-1131. Hashish: Studies of long-term use. 94, 723-729. Schools and suspensions: Self-reported crime and the growing use crime and the growing Schools and suspensions: Self-reported 795-802. 544-547. Ganja in Jamaica, a medical anthropological study of chronic marijuana study of chronic Ganja in Jamaica, a medical anthropological European Journal of Pediatrics, 159, European Addiction, Journal of College Student Development, 39, Journal of College Student Cannabis and cognitive functioning. ashington, D.C.: Justice Policy Institute. Journal of the American Medical Association, 275, Journal of the American 2119-2126. W Adolescence, 144, Journal of Consulting and Clinical Psychology, 68, Journal of Consulting and Clinical Psychology, The Hague: Mouton. 909-915. anner, J., Davies, S. & O’Grady, B. (1999). Whatever happened to yesterday’s rebels? Longitudinal rebels? (1999). Whatever happened to yesterday’s B. J., Davies, S. & O’Grady, anner, T of youth delinquency on education and employment. effects Pope, H. G., Gruber, A. J., Hudson, H. I., Huestis, M. A. & Yurgulun-Todd, D. (2001). I., Huestis, M. A. & Yurgulun-Todd, A. J., Hudson, H. Pope, H. G., Gruber, of long-term cannabis users. performance Neuropsychological 58, H., Milne B. J. & Caspi, A. (2001). Persistence and perceived E., Harrington, T. Poulton, R., Moffitt, among young adults: Implications for policy. consequences of cannabis use and dependence Zealand Medicine Journal, 114, Drinking behaviour among teenagers in Switzerland A. (2000). & Michaud, P. Narring, F. Y., Rodondi, P. with lifestyles. and correlation Rubin, V. & Comitas, L. (1975). Rubin, V. use. and M. & Diego, M. A. (2001). Adolescents’ academic expectations Sanders, C. E., Field, T. achievement. M., Christiansen, K., McRee, Kadden, R., Miller, T., R. A., Babor, Solowij, N., Stephens, R. S., Roffman, J. (2002). Cognitive functioning of long-term heavy cannabis users seeking treatment. B. & Vendetti, Journal of the American Medical Association, 287, Shiraldi, V. & Zeidenberg, J. (2001). & Zeidenberg, Shiraldi, V. Solowij, N. (1998). of suspensions. among for the assessment of coping self-efficacy N. E. (1999). A brief measure S. M. & Turner, Sklar, alcohol and other drug users. following cessation of cannabis use? Solowij, N. (1995). Do cognitive impairments recover Life Sciences, 56, Stefanis, C., Dornbush, R. & Fink, M. (1977). L. (2000). Comparison of extended versus brief interventions for R. & Curtin, Stephens, R., Roffman, marijuana. Plucker, J. A. & Dana, R. Q. (1998). Alcohol, tobacco, and marijuana use: Relationships to students’ tobacco, and marijuana use: Relationships J. A. & Dana, R. Q. (1998). Alcohol, Plucker, achievement. creative Pope, H. G. & Yurgulun-Todd, D. (1996). The residual cognitive effects of heavy marijuana use in cognitive effects The residual D. (1996). Pope, H. G. & Yurgulun-Todd, college students. 96 An Overview of Scientific and other Information on Cannabis NACD 2004 cognitive functions:Apreliminary report. W Adolescence, 21, 70, Impulsive choicesandproblem behavioursinearlyandlateadolescence. W marijuana useamongpublichighschooladolescents. Wi Chapter 3 V ingilis, E.&Wade, T. J.&Adlaf,E.(1998).Whatfactorspredict studentself-ratedhealth? ulfert, E.,Block,J.A.,Santa,A.Rodriguez,M.L.&Colsman,(2002).Delayofgratification: ig, N.&Varma, V. K.(1977).Patternsoflong-termcannabisuseinNorthIndiaanditseffects on nnail, S.D.(1995).Relationshipbetweenphysicalactivityandcigarette, smokelesstobacco,and 533-552. Psychological ConsequencesofCannabisUse 83-97. Drug andAlcoholDependence, Journal ofSchoolHealth, Journal ofPersonality, 2, 211-219. 65, 438-442. Journal of NACD 2004 An Overview of Scientific and other Information on Cannabis 97 634) on € 1269) on € Johnny Connolly 507) and £1000 ( € 380) on summary conviction and £500 ( € 1269) fine or both. For conviction on indictment, the maximum € 1,269) fine or both. For a conviction on indictment, the penalty is a 3-year 1,269) fine or both. For a conviction on indictment, € evisits aspects of the gateway theory. Attention is drawn to the major value conflicts surrounding the Attention is drawn to the major value conflicts surrounding evisits aspects of the gateway theory. sentence is seven years’ imprisonment, a discretionary fine or both. sentence is seven years’ imprisonment, a discretionary years. The National Crime scrutiny in recent The legal status of cannabis has come under increased for arguments Forum, established by the Minister for Justice, Equality and Law Reform in 1998 heard 1998). Some contributors argued and against decriminalisation of cannabis (Government of Ireland, associated with them. that the illegality of certain drugs gave rise to many of the problems legal situation was criticised on the basis that it brings young people into the criminal The current and to and exposing him or her to arrest culture justice system, drawing the user into a law-breaking who have a vested contact with criminal elements. By placing the trade in the hands of criminal gangs to crime to pay encouraged to resort that the users are it is argued in maintaining high prices, interest that the glamour attached to criminals who make vast profits is also a concern for their habit. There which can be alluring to young people. It was also drug dealing sets up a counter-culture from and regulation control suggested to the Forum that decriminalisation would bring drugs within official prison sentence, a fine at the discretion of the court or both. The supply of drugs within a small circle prison sentence, a fine at the discretion of a commercial of friends has been held to be a mitigating factor in sentencing while the presence involved, has been seen as an aggravating factor (Charleton and friends are motive, even where McDermott, 1998). conviction, is The maximum penalty for the possession of any drug other than cannabis, on summary 12 months’ imprisonment, a £1000 ( indictment. For a second offence, the maximum fines are £400 ( £400 the maximum fines are indictment. For a second offence, and on, the maximum fine for a summary conviction is a 12-month offence indictment. For a third prison sentence, a £1,000 ( Legislation of Cannabis in Ireland Legislation of Cannabis the Misuse of Drugs Act, 1977. Section 3 makes it under differently Cannabis has always been treated drug in his possession. Section 27 of the Act as amended for a person to have a controlled an offence substance is cannabis and the the stipulates that where by Section 6 of the Criminal Justice Act, 1984 it for his or her own use the penalty should be a fine on court is satisfied that the defendant possessed up to a maximum of £300 ( the first offence This chapter examines the major sociological and criminological consequences of cannabis use. In the major sociological and criminological This chapter examines is to cannabis in Ireland situation with regard the legal a context for this review, to provide order that is in a way has been treated the fact that over the last 25 years cannabis described, especially are consequences of the use of cannabis other illegal substances. Some social from different Evidence regarding educational outcomes and marginalisation. problems, examined including family of the cannabis is evaluated. Features violence acquisitive crime and drug-related cannabis-related distribution, the involvement of organised and examined, particularly wholesale production market are to cannabis availability. crime and issues related of harm and in this context the probability that increase This chapter also considers social factors r the legal status of the drug. on the debate regarding use of the drug and the literature Criminological and Sociological Criminological Use of Cannabis Consequences Overview Chapter Four Chapter 98 An Overview of Scientific and other Information on Cannabis NACD 2004 a renewed discussionastoits legalstatusinIreland The changeintheclassificationofcannabisUnitedKingdom inJanuary2004hascontributedto drug use. help othersinamedicinalwayorbecausetheyfeelitmightassist intheprosecution ofmore serious cannabis leadstoharder drugs. Thosewhoagreed withachangedidsoonthebasisthatitmight strongly withsuggestedchangestothelegalstatusofcannabisonbasisthattheybelieved August andDecember2001.Themajorityofrespondents whoanswered thisquestiondisagreed very issue ofcannabisdecriminalisation(Connolly, 2003).Thestudysurveyed44localresidents between associated withdrugdealinganddrug-related anti-socialbehavioursoughtrespondents’ viewsonthe A localdoor-to-door surveyofopinioninaDublininner-city area whichhasendured severe problems r per centofrespondents agreed thatcannabisuseshouldbedecriminalisedwhile75percentof among theyoungmembersof(adult)populationsurveyed”(p.xiv).Regarding policyoptions,24 authors pointout,“thissomewhatexaggeratedsenseoftheeffects ofillegaldrugswaslesscommon cent believedthatonecouldbecomedependentondrugsafterjustexperience.Although,the believed regular useofcannabiswasjustasdangerous to healthasregular useofheroin. Over40per approximately 77percentbelievedalldrugstobeequallyharmfulhealthandoverhalf(54%) experience ofcannabisandknewpeoplewhohadtaken(Bryanetal.,2000).However, attitudes andbeliefsinIreland foundthattheyoungerurbansectorofsocietyhadagreater personal public opinionwasopposedtosuchachange.Anationwidesurveyofdrug-related knowledge, It wasemphasisedtotheNationalCrimeForumbyopponentsofcannabisdecriminalisationthatIrish be approached onanEU-widebasis. drug problems elsewhere. Itwasargued thatanymovetowards decriminalisationmightmostusefully prohibited intherest oftheEUwere more availablehere, there mightbeadisplacementtoIreland of contrary tointernationalconventionswhichIreland isasignatory. Itwasalso feltthat,ifsubstances (Government ofIreland, 1998,78).Itwasalsoargued thatamovetowards legalisationwouldbe such asalcoholbodedillforthecontrol oftheuseotherdrugsshouldtheybelegalised” point that“theineffectiveness ofourefforts tocontrol theabusebyyoungpeopleofalegaldrug become more widespread intheabsenceoflawenforcement measures. Theforumhighlightedthe encouraging theuseofdrugsatatimewhenneedwastodiscourageit;thatdrugwould Those opposedtodecriminalisationargued thatsuchamovewouldsendoutthewrong signal,thus underground salewouldhavelessincentivetorecruit furtherusers. if drugswere availablemore openlyinacontrolled way, dealerswhocurrently profit from its and sofacilitatequalitycontrol andfacilitatetheregulation oftoxicity. Furthermore, itwasargued that Chapter 4 4 3 they are more orlesscoming intolinewithhowweare” after reclassification, intheoryyoucanstillgetatougherprisonsentencethanhere, soinmanyways National DrugsStrategystatedthat,“We’re quitehappywithhowthelawstands...InUK,even changed inthisarea, on31st January, 2004,NoelAhernTD,MinisterofStatewithresponsibility forthe espondents were opposedtothis. Where 31stJanuary2004. thegrass isgreener TheIrishTimes Reclassification ofcannabis intheUKDrugnet Ireland, Issue10,March 2004. For ananalysisof the recent changeincannabisclassification intheUnitedKingdomseeConnolly J; Criminological andSociologicalConsequencesofCannabisUse 3 . Inrejecting suggestionsthatIrishlawshouldbe 4 . NACD 2004 An Overview of Scientific and other Information on Cannabis 99 Criminological and Sociological Consequences of Cannabis Use Cannabis of Consequences and Sociological Criminological Chapter 4 Chapter mains even when controls are applied for a range of co-variates and possible confounding factors. are mains even when controls to (relating jected for all or part of the year or risked automatic denial for not answering the question efers to a mechanism called ‘cumulative continuity’, where the “adolescent’s interactional style leads the “adolescent’s where efers to a mechanism called ‘cumulative continuity’, Education and Employment Problems motivation and poor As shown in Chapter 3 cannabis use has been found to be associated with loss of & Hall (2000), it was shown that the association educational achievement. In the studies of Lynskey re lifestyle. These authors suggest that the causal mechanisms may be the adoption of an unconventional use study in the US found that cannabis A prospective quite strong. the link is For whatever reason, (Brain et al., 2000). Another mediating factor may be the college graduation negatively predicted shown to be associated with cannabis use. For example, Fergusson that were psychological problems associated with a et al. (2002) found that cannabis use among 14-21-year old New Zealand youth was and suicidal thoughts. including depression range of adjustment problems For example, students convicted of cannabis Drug laws can have an impact on educational prospects. ineligible for federal student aid for university for a designated in the US, are possession offences 43,436 were period of time. “Of the 9.8 million applicants for aid for the 2001-2002 school year, re 2001). An Australian study found that, although a conviction for cannabis use)” (Associated Press, (of a group cannabis conviction had little impact on subsequent cannabis use, “a significant minority with the law further problems a cannabis conviction) reported Australians who had received of 68 West and travel opportunities” (Lenton & relationships with employment, accommodation, and problems Heale, 2000). In this section the evidence is examined on the relationship between cannabis use and behavioural between cannabis is examined on the relationship In this section the evidence and marginalisation. education, employment problems, also chapter 3) (See Early Conduct Problems Behavioural and and early between early conduct problems the relationship A Norwegian study sought to investigate (Pedersen, 2000). The on possible gender differences onset of cannabis use, with special emphasis sample in their early longitudinal study of a national representative study consisted of a prospective and subsequent cannabis association between early conduct problems teens. It found a strong upon cannabis initiation in effect found to have a moderate were initiation. Serious conduct problems in girls. The study did not effects had strong and covert conduct problems aggressive boys, whereas an personality traits associated with impulsiveness and sensation seeking. In seeking for control author and drug use the of conduct problems explanation for the link between early development r question” (Pedersen, the behaviour in that reinforces an environment him or her to select and create youth ordinary from alienate the adolescent problems 2000). The author hypothesises that conduct youth. deviant with more fostering relations while groups, high levels of drinking and found that “factors such as unemployment, truancy, Spruit (2002) Similarly, heavy may be a contributory factor in the case of smoking, and sometimes behavioural disorders”, users of cannabis. Social Consequences for the User Social Consequences 100 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 4 Committee (1968) notedthat,“IntheUnitedKingdom thetakingofcannabis hasnotsofarbeen regardsspecifically oncannabis.With tothealleged links betweencannabisandcrimetheWootton Dependence (TheWootton Committee)(Advisory onDrugDependence,1968)focused A subsequentUKcommitteeof leadingexperts,theUnitedKingdom’s AdvisoryCommitteeonDrug small” (TheLaGuardia Report)(NewYork Academy ofMedicine,1944). of speculation.Theexpectancymajorcrimesfollowingthe use ofcannabisinNewYork Countyis drugs. Whetherthefirstoffenders charged withtheuseofmarijuanagoontomajorcrimeisamatter cases…the earlieruseofmarijuanaapparently didnotpredispose tocrime,eventhatofusingother Following ananalysisofdrugoffender records, thereport statedthat“Inthevastmajorityof had comeintoconflictwiththelaw. interviewed lawenforcement officials andexaminedtherecords ofanumbercannabisuserswho r as muchitfocusedonissuesthatare stillofcentralconcern.Thestudysoughttoidentifythe almost 60yearsagoisstillrelevant (TheLaGuardia Report) (NewYork AcademyofMedicine,1944)in A studyconductedbytheNewYork AcademyofMedicineandpublishedbytheCityNewYork Drug-related Disorderly Behaviour cannabis-related traffic offences. specifically violenceassociatedwithcannabisuse.Thissectionalsoconsidersevidenceon These includedisorderly conduct arisingfrom use,acquisitivecrimeassociatedwithuseand Below weconsideravarietyofconsequencescannabisuseonthesocialbehaviouruser. Consequences ontheSocialBehaviourofUser evidence tothateffect. damages relations between police andyoungpeopleitdidoffer quitepowerfulcircumstantial concluded thatalthoughthesefindingsdidnotamounttoproof thatthepolicingofcannabis 57 percentofnon-cannabisusersfelt‘fairlytreated’ compared with28percentofusers.Theauthors were markeddifferences inthesatisfactionlevelsofcannabis-usingandnon-usingBCS respondents. nearly twiceaslikelytoreport beingapproached bythepolice asnon-users(Mayetal.,2002).There associated withtheimpactofpolicingcannabisinEnglandfoundthatuserswere A studyofthefindings2000BritishCrimeSurvey(BCS)whichconsidered thesocial costs further below. cannabis useisseenasa‘normalised’aspectofbehaviour. Thisconceptwillbediscussed offenders, andleadtoadefianceofthelaw. Suchfindingsare exacerbatedinacontextwhere under certainconditions,reinforce rulebreaking, underminerespect forlegalinstitutions,alienate unjust andunfairthatresearch from anormativeperspectivehasshownthatsuchexperiencescan, Lenton andHeale(2000)foundthatoffenders canperceive thelawanditsofficers asheavy-handed, marginalisation andalienationfrom societalnorms(Hall, 2001). It hasbeensuggestedthatcannabisuseleadingtoprosecution forsuchbehaviourmaycontribute to Marginalisation (SeealsoChapter2) elationship betweencannabis,crimeandjuveniledelinquency. Thecommitteeconductingthestudy Criminological andSociologicalConsequencesofCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 101 Criminological and Sociological Consequences of Cannabis Use Cannabis of Consequences and Sociological Criminological Chapter 4 Chapter ith regards to the link between cannabis use and acquisitive crime, it has been difficult to identify, to identify, crime, it has been difficult to the link between cannabis use and acquisitive ith regards elationship between heavy cannabis use and reporting the need to acquire money to buy drugs as the need to acquire elationship between heavy cannabis use and reporting egarded, even by the severest critics, as a direct cause of serious crime”. With regards to the alleged With cause of serious crime”. a direct critics, as regards even by the severest egarded, Drug-related Acquisitive Crime Drug-related W of the use of the drug as distinct from committed as a result in the case of cannabis, those offences between to identify a causal link Thus it is difficult anyway. those which would have been committed cannabis use and crime (Hough et al., 2001). cannabis use by juveniles and crime. An between Some studies have suggested a relationship between relationship cannabis and crime suggests a strong of the links between Australian review 1998). The study & Coumarelos, cannabis use by juveniles and their participation in crime (Trimboll crime to fund their to property is that juveniles resort relationship for this indicates that the reason were offences consumption of cannabis. Baker (1998) found that the odds of participation in property while Salmelainen (1995) found a who used cannabis frequently for students almost five times greater r for committing crime. the main reason findings do not conclusively show that all (1998) point out, these & Coumarelos As Trimboll become involved in crime, or if they are heavy cannabis users will inevitably adolescents who are factors that may be background serious crime. There to more involved in crime that they will progress British review involvement with cannabis. A recent crime and also towards them towards predispose likely than others to be involved more on this issue concluded that …. ‘those who use illicit drugs are is no causal link between use of either ecstasy or in general, there in crime, and vice-versa. However, et al, 2001). crime’ (Hough cannabis and property r Government Commission of Inquiry a Canadian cannabis and criminal behaviour, association between ) (Canadian Government, 1970) reported Use of Drugs (The Le Dain Commission into the Non-Medical (of cannabis) in the effect find scientific documentation of a criminogenic that it was “unable to international literature”. of the fact that it is a criminal offence cannabis and crime exists by virtue Obviously the link between however that cannabis is a cause of crime. Criminal to possess cannabis. This does not mean use. Studies in Britain and America show the onset of cannabis may have existed before propensities they started taking drugs and 50% before criminal offences that about 50% of drug users committed did not (Bean & Wilkinson, those 1988). Given that not all cannabis users commit crimes other than plausible explanation for links between that a more associated with possession, it can be argued of a deviant lifestyle (Bennett, 1998; Bennett and expressions morbidities might be that both are Sibbitt, 2000). between for an explanation for the linkage has focused on the search deal of research A great cannabis operates as a illicit drug use. The idea that cannabis use, crime and further more-serious used to illustrate these connections. The gateway gateway to further drug use is a central theory 2). theory will be discussed below (see also Chapter 102 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 4 towards violentandanti-socialbehaviour. may involveassociationwithdeviantpeersanddealerswhich in turnmayresult inagreater tendency may promote intimidationand violence’(Rigter&Van Laar, 2002).Inotherwords theuseofcannabis individuals …maybecomeearlyandactiveparticipantsinthe illegal economyofdrugmarkets,which complex relationship betweencannabisuseandanti-socialbehaviour. ‘Cannabis-dependent However, anotherrecent review whichconsidered thelinkbetweencannabisandviolenceindicatesa cannabis users. frequently whiletheoddsfor participationinmaliciousdamagewere three timesgreater forfrequent The oddsforparticipationinassaultwere more thantwo times greater forstudentswhousedcannabis damage, evenwhencontrols were appliedforbothdevelopmentalfactorsandtheuseofotherdrugs. that cannabisusewasasignificantpredictor ofstudents’participationinassaultandmalicious between theuseofcannabisandparticipationinviolentcrime(Baker, 1998).Thislatterstudyfound offences (Harrisonetal.,2001).Inaddition,anumberofAustralianstudieshavefoundanassociation that cannabisuseincreases the probability ofbeingboththevictimandperpetratorviolent frequency ofcannabisusewas associatedwithfrequency ofviolentoffences. There isalsoevidence Chapter 3from anIrishperspective.Furthermore, astudy by Friedmanetal.(2001)foundthat frequently associatedwithaggressive behaviour. Thismatterhasbeengivendetailedattentionin Despite thisearlierconsensus,there isevidencethatheavyuseofcannabisamongjuveniles aggressive impulsesandoperates asacalminginfluenceontheuser. largely discredited (Goldstein,1985).Indeed,somestudies havesuggestedthatcannabistakesaway Early suggestionsofapsychopharmacologicallinkbetweencannabisuseandviolentcrimehavebeen networks, isviewedbyGoldstein(1985)asthemostcommonintermsofdrugs-violencenexus. bystanders orvictimresistance. Systemiccrime,whichisassociatedwithmanyformsofdrug distribution during thecommissionofcrimeasaresult ofthedrugusers’nervousness,interventionby above. Crimeisengagedinforthepurposeoffeedingdrughabit.Associatedviolencecanoccur model illustratesthepopulistviewaboutlinkbetweendrugsandacquisitivecrime,asdiscussed drug canhaveanamelioratingeffect onbehaviourandactasacrime-reduction agent.Theeconomic victimisation orotheroffences suchasvandalism.There canalsobeareverse effect here whereby the excitable andirrationalmayexhibitviolentordisorderly behaviour. Suchbehaviourcanleadto The psychopharmacologicalmodelsuggeststhatindividuals,asaresult ofdruguse,maybecome violent crime. overlap, theyare usefulforexplanatorypurposesasweseektoidentifythelinkbetweencannabisand psychopharmacological, theeconomically-compulsiveandsystemic.Althoughthesecanoften Goldstein (1985)identifiesthree possiblewaysinwhichdrugsandviolentcrimeare related; the Drug-related Violence alcohol’ (Corrigan,2003). having control ofthevehicle.Intoxicantsincludealcoholand drugsandacombinationof or pedalcycle‘whileunderthe influenceofanintoxicanttosuchextentasbeincapable of In Ireland, theRoadTraffic (amendment)Act,1978makesitanoffence todriveacar, motorcycle, truck Drug-related Traffic Offences Criminological andSociologicalConsequencesofCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 103 Criminological and Sociological Consequences of Cannabis Use Cannabis of Consequences and Sociological Criminological Chapter 4 Chapter ithin the European Union, there has been increased activity in both the legislative and the has been increased Union, there ithin the European mains unknown, there was a lack of significant evidence of the effects on driving ability of the use of of the effects was a lack of significant evidence mains unknown, there evealed many ‘false negatives’ and correctly identified only 18-25% of the THC positives in reference identified only 18-25% of evealed many ‘false negatives’ and correctly and that should be improved, impairment for drug-related ecommend that techniques to test drivers countries and from twenty-seven European from practitioners, doctors and police officers esearchers, types of drugs (licit or illicit) used, extent of to the different eview found no specific criteria relating In the international literature, the link between drug use and driving accidents and offences has and offences the link between drug use and driving accidents In the international literature, & Fergusson years (Gemmell et al.,1999; concern to policy makers in recent become of increased 2001; Ramaekers et al., et al., 2001; Flynn et al., & Ramaekers, 2001; Tunbridge Horwood, 2001; Lamers has 2002). This issue Ireland, Lenne et al., 2002; Sexton et al., 2002; Drugnet 2002; & Terry, 2002; Wright discussed in chapter 2. been already constrained law have severely testing procedures adequate roadside Attempts to develop available onsite tests (2002) conclude that “Currently Ramaekers et al. in this area. efforts enforcement cannabis use. Saliva tests indication of recent a foolproof of urine, saliva and sweat do not provide r cannabis use for suspecting good grounds drug tests may well provide roadside blood…Results from of THC in blood”. Research demonstrating the presence in drivers, but need further confirmation by Laboratory had highlighted the Research et al. (2001) for the Transport conducted by Tunbridge of establishing causation in this area. difficulties also pointed to what it saw as the inadequacy of testing The Runciman Committee (Ashton, 2000) It went on to of police training in drug-testing equipment. equipment and the poor standards r the necessary training. for testing should receive responsible all police officers together public servants, brought in April 1999 by the Pompidou Group A seminar organised r (Council of Europe, and drugs traffic of road in respect the United States to consider the main areas and detection; the legal aspects including practical aspects of law enforcement 2000). These were and rehabilitation. epidemiology and risk assessment and prevention prevalence, that the distinction between licit and the seminar were from The primary conclusions which emerged safety was not useful. It was felt that it was not their illicit substances in the context of road scale of the problem put; the real classification which matters, but the use to which substances are re needed to be expanded in this area. the substances concerned and that research Union Member drug use and driving in European of the existing legal situation regarding A review driving under the influence of for prohibiting States found that all Member States had legal provisions the codes (Gemmell et al.,1999). However, substances besides alcohol in their traffic psychotropic r illegal blood drug use, or definition of an influence; no legal limits for drugs and no laws defining evidence to define safe was insufficient found that there limits of illicit drugs or medicine. The review pharmaceutical package concerned. Since 1994, European drugs other than alcohol were levels where of the drug on inserts have had to include statements concerning the potential deleterious effect driving (ibid). W Act of 2001, a decision was made to exclude a operational levels. In Austria, in its Road Traffic in accidents. In June 2001, a Finnish working on obligatory drug tests for drivers involved provision a relatively tolerance for drugs and driving. In Germany, zero proposed focused on this area group in cases of for an extensive medico-psychological testing procedure provides new regulation 104 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 4 countries inWestern Europe, andfrom South-West Asia. re hydroponic cannabishasgainedimportanceinEurope. Itisthoughtthatthemainroute forcannabis Saharan Africa,South-EastAsia,and,inrecent years,from Albania.Also,domestically-grown been re-directed tomarketsinWestern Europe, where itcompeteswithcannabisherbfrom Sub- expected todiminishtheimportanceoftheseroutes. SomeColombiancannabisherbhas already although theUNODCreports thatincreasing levelsofhighqualityproduction inNorthAmericaare The principaldrugtrafficking routes forcannabisherbare from MexicoandColombiatotheUSA, quarter inSouthernAfrica(muchofitSouthAfrica). 1999 (ibid).More thanhalfofthecannabisherbseizedworldwidewasinNorthAmericaandnearlya metric tonnesofcannabisherbwere seized,whileapproximately 4,000metrictonneswere seizedin Cannabis isthemostwidelytrafficked drugglobally(UNODC,2000).In2000approximately 4,500 Wholesale Production andDistribution involved inthevariouslayersordimensionsofcannabismarket. It shouldbenotedthatthere maybeagreat dealofoverlapbetweenthenetworkindividuals the “localmarket”(Luptonetal.,2002). and Hobbs(2001)asthe“middlemarket”thenthoseinvolvedinitsdistributionataretail level, the “internationalmarket”,thoseinvolvedinitsimportationanddistribution,describedbyPearson cannabis marketcanbedescribedasincorporatingthoseinvolvedinitsproduction andimportation, For thepurposeofsimplicity, andintheabsenceofanyspecificresearch ontheIrishdrugsmarket, The CannabisMarket of illicitsubstances. r while undertheinfluenceofdrugs.InMarch 2001,theUKGovernmentintroduced legislation to accidents.Thiswasfacilitatethedesignofaspecificandeffective legislationtoaddress driving r 2001, legislationwasintroduced totestindividualsinvolvedinroad traffic accidentssoastoconduct are beingutilisedtocounteractlegalisationtendencies”(Neumeyer, 2002).InPortugalandFrancein possession. Ithasbeenargued that,“undertheveiloftraffic safety, harshandrepressive drugpolicies Some traffic lawshaveevolvedtoprovide fortherevocation ofdrivinglicencesincasescannabis (Bollinger &Quensel,2002). suspected cannabisuse,tobepaidforbythedriving-licenceholderwhoisplacedundersuspicion long coastlineisolated inmanyareas, maybeused asanaccesspointfortransit totheUKandEurope. seized inthecountryrecent yearsare forthehomemarket.ItisalsospeculatedthatIreland, withits cross-channel ferries,andonsea-goingyachts.TheGarda Síochánabelievesthatmostofthe drugs through theIberianpeninsulatosouthcoastofIreland. Itistransportedinfreight trucksusing cannabis seizures were knownto haveoriginatedinSouthAfrica.Mostofthecannabiscomes up have originatedinPakistan,Afghanistan andLebanon(Moranetal.,2001).Inrecent yearssomeherbal The cannabisresin inIreland originatesmainlyfrom Morocco, whilesomesmallerseizures are knownto egulating thetestingandrelated procedures onindividualssuspectedofdrivingundertheinfluence esearch ondrugsanddrivingintotheleveltypeofdruguseamongdriverstheircontribution sin intoEurope (theprincipalformofthedrugusedinIreland), isfrom Morocco viaSpaintoother Criminological andSociologicalConsequencesofCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 105 Criminological and Sociological Consequences of Cannabis Use Cannabis of Consequences and Sociological Criminological Chapter 4 Chapter iolence in Connection with Production and Distribution iolence in Connection with Production Although there is clear evidence of violence associated with the drug trade, in the absence of any is clear evidence of violence associated with the drug trade, in the absence Although there is impossible to state with any clarity the extent to which adequate studies of Irish drug markets, it trade in cannabis. A number of popular crime books have violence is associated specifically with the the drug individuals or gangs involved with prominent been written by investigative journalists about when considered (Reynolds, 1998; Williams, literature, such trade in Ireland 2001). The evidence from is a significant amount of violence does suggest that there along with newspaper and court reports that and drug seizures media reports associated with the illegal trade in drugs. Also, it appears from drugs. For example, the gang discussed of overlap between trades in different is some degree there by Williams (2001) appears to have been involved in dealing cocaine as well as cannabis. It would be information as to the extent of overlap between the trade in cannabis and reliable useful to have more it exists. the trade in other drugs, where A study on homicides in murders. in gang-related has witnessed an increase years, Ireland In recent connected to disputes 1992 and 1996, fifteen homicides were suggested that between Ireland 2001). Although further investigation would over the supply of illicit drugs (Dooley, concerning control to the cannabis drug had any specific relationship to identify as to whether these murders be required drugs suggests a possible overlap within the trade in different is some trade, the fact that there connection. crime and anti-social behaviour of drug-related high levels Studies by Connolly (2002, 2003) revealed This behaviour, inner city. market level in Dublin’s associated with drug dealing at the local or ‘retail’ known as a site which included muggings and other assaults, was associated with a particular location, being used and that cannabis was regularly drug dealing. Although a local survey found of regular use and the sold at this location, the study did not investigate specific linkages between cannabis crimes and nuisance associated with this location. V Most of the research conducted into organised crime and its involvement with drug trafficking has and its involvement with drug trafficking crime conducted into organised Most of the research focus on such is an increasing although there the USA (South, 1995; Dorn et al., 1992) come from specifically on None of the studies consulted focused & South, 1995). (Ruggiero studies in Europe cannabis. is distribution of drugs within the country that the however, Síochána believes, the Garda In Ireland, members of the same by networks of criminal gangs. In some cases these gangs involve organised book by investigative recent is supported by a relatively family (Moran et al., 2001). This contention journalist Paul Williams of crime which focused on the gang involved in the murder (2001), of both Guerin in 1996. This book suggests the significant involvement Veronica correspondent trade. It also suggests that crime networks in the Irish cannabis international and national organised The and ammunition. of cannabis, cocaine, firearms the same gang was involved in the importation cannabis shipments. trips by gang members to the Netherlands to organise book describes regular then sold the cannabis to a network of dealers in It suggests that a second level of gang members local supply (Williams, onward for 2001). Ireland Involvement in Organised Crime Organised Involvement in 106 An Overview of Scientific and other Information on Cannabis NACD 2004 Most research conductedonretail-level drugdealingisfrom theUSA The LocalRetail‘Market’andCannabisAvailability illegally acquired bytheganginvolvedinhermurder aswellinotherdrug-related matters. including cannabis.Mediareports suggestthatCABhasbeenparticularlyactiveinpursuingtheassets of themurder ofjournalistVeronica Guerinbymembersofaganginvolvedinthetrafficking ofdrugs, Reports, 1998-2001),itisworthpointingoutthattheCABwasestablishedinimmediateaftermath no detailedindicationastotheextentornature ofitsinvestigationsinthedrugsarea (CABAnnual serious crimewithaviewtoconfiscatingsuchassets.Althoughtheannualreports oftheCABprovide Bureau (CAB)wasestablishedwithpowerstofocusonillegallyacquired assetsofcriminalsinvolvedin offences includingmoneylaundering.UndertheCriminalAssetsBureau Act1996,theCriminalAssets for theseizure andconfiscationofassetsderivedfrom the proceeds ofdrugtrafficking andother The CriminalJustice(Proceeds ofCrime)Act1996andtheCriminalAssetsBureau Act1996provided Money Laundering Chapter 4 5 60 percentsaid thattheyhadbeenoffered atleastoneillicitsubstance, cannabisbeingthemost by itbeingpassedaround agroup offriends,from astranger orbybuyingit(Brinkleyetal.,1999).Just most commonwaysinwhichpupils obtainedillicitsubstances,includingcannabis,were from afriend, A studyof983Irishsecond-year pupilsin16schoolstheDublinmetropolitan area found thatthe someone theyknewquitewell (Pompidou Group, 2000). adolescents whohadusedanyillicitdrugin1999obtained thedrugforfirsttimefrom 29 percentacross thecountries inthestudy. TheESPAD surveyalsofoundthatthemajorityof was “very”or“fairly”easytoobtain.Thisthehighestfinding ofallcountries,theaveragebeing r cannabis waseasilyavailableinschoolwhile78percentreported availabilityinanyother place. With of adealer”and“school”(PompidouGroup, 2000p131).23percentofIrishstudentsreported that a bar”wasthemost-commonlymentionedlocation,“street, parketc.”second,followed by“house Irish studentsknewofsomeplacetheycouldeasilybuycannabis (PompidouGroup, 2000). A“discoor Irish fifth-yearstudents,considered thequestionofdrugmarketsandavailability. Two-thirds ormore of drug useamongstudentsin30European countries(Hibelletal.,2001)includingasampleof1,849 Moore, 2002p50).TheEuropean SchoolSurveyProject onAlcoholandOtherDrugs, whichsurveyed 1999, 88.9percentofhighschoolseniorssaidcannabiswas‘fairly’or‘veryeasy’toobtain(Wodak & school seniorssurveyedreplied thattheyhadfoundcannabis‘fairlyeasy’or‘verytoobtain.In A USstudywhichconsidered theperiodfrom 1975to1998, foundthatatleast82percentofhigh nature oftheretail marketor, atleast,theavailabilityofcannabisstreet level. who haveadmittedtousingcannabisandothersimilarstudiesdogivesomeindicationasthe carriers, trafficking smalleramountsofcannabis(Sinclairetal.,2001).Surveyresearch amongthose larger distributionnetwork,involving smalleramountsofthedrug.Thatis,there are manymore Unit believesthat,inthelastfewyears,nature ofthecannabismarketseemstohavechangeda No research studieshavebeenconductedinIreland inthisarea. TheGarda SíochánaNationalDrugs other jurisdictionsontotheIrishsituation. nature ofthedrugtradesuggeststhatcautionmustbeexercised before transferringfindingsfrom the regional variationsindrugmarketstheUK(Pearson&Hobbs,2001).Theflexibleanddiffuse egards totheperceived availabilityofcannabis,59percentIrishstudentsresponded thatcannabis For areview seePearson,G.andHobbs,D. (2001). Criminological andSociologicalConsequencesofCannabisUse 5 . Arecent UKstudyhighlights NACD 2004 An Overview of Scientific and other Information on Cannabis 107 13 per gram (Moran € Criminological and Sociological Consequences of Cannabis Use Cannabis of Consequences and Sociological Criminological Chapter 4 Chapter spondents made a sharp distinction between acceptable and unacceptable drugs with cannabis in spondents made a sharp distinction between acceptable and unacceptable drugs outine street encounters with friends and acquaintances were found to provide the most reliable and the most reliable found to provide friends and acquaintances were encounters with outine street In terms of the risk of further harm from cannabis use, Clayton’s (1992) definition of risk is useful. He cannabis use, Clayton’s In terms of the risk of further harm from individual characteristic, situational condition, or defines a risk factor as “an individual attribute, of drug use or abuse or a transition in level of the probability context that increases environmental exposes the user involvement with drugs” (Clayton, 1992). Regular use of cannabis, such as daily use, consequences (Hall & Solowij, 1998) (see Chapter risk of adverse health and psychological to greater of harm the probability to identify the factors that increase 3). It is particularly important therefore (Parker has become a ‘normalised’ aspect of youth culture argue to a drug which some in relation et al., 1998). drug use among young people that to general Brinkley et al. (1999) point out in relation to be much more “….experimentation and a variable pattern of use and cessation have been found that many young people regulate use” (p3). Many studies reveal common than heavy or problematic of harm. A longitudinal study which described with perceptions their drug use patterns in accordance of England, found that evolving patterns of drug use among young people in the North West re the former category (Parker et al., 1998). among heavy A survey sample of 2,641 UK school students aged 15-16 examined possible differences and in terms of patterns of illicit using cannabis 40 times or more) cannabis users (those who reported (but smallest in number) was largely & Plant, 2002). The first group (Miller drug use within the group with identified as being clearly unhappy, were A second group distinguished by anti-social behaviour. mood and low levels of self-esteem. and friends, high levels of depressed parents little support from Social Factors that Increase the Probability of Harm the Probability Social Factors that Increase commonly offered. The places where students were most commonly offered illicit substances were on illicit substances were most commonly offered students were The places where commonly offered. home. at a rave or disco and at a friend’s the street, acquainted with city found that the majority were inner people in Dublin’s A survey of 57 young acquainted with although fewer were and means of accessing illegal drugs individuals who had ways of illicit drugs as to the procurement however, This was not seen as a barrier, known drug dealers. r drugs of choice (Mayock, 2000). to respondents’ familiar access routes 2003). This city (Connolly, north inner supported by a study conducted in Dublin’s These findings are about drug-related survey of attitudes and perceptions a local door-to-door which incorporated study, while 24 sold in the past year, had witnessed drugs being crime, found that 53 per cent of respondents being sold at a specific location (ibid). per cent stated that they had witnessed cannabis unit among second-level students in Waterford/ Síochána research A study conducted by the Garda taken by 89 per cent of divisions found that cannabis was the first drug Kilkenny and Kerry Garda supplied the drugs (Sarma having used drugs. In 70 per cent of cases friends had those who reported et al., 2002). per gram prices although the price of cannabis resin No studies have been conducted into drug stable over the past number of years, at relatively appears to have remained et al., 2001). 108 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 4 r harmful, druguse.The‘gateway’theoryhasemerged asanimportantexplanatorymodelinthis associated withsuchuseandwhycannabismightleadto offending behaviourortofurther, more In suchacontextitisimportanttoidentifythosefactorsthatincrease theprobability ofharm acceptance. problematic feature ofuse”.Thestudyalsofoundthatother drugusewasnotviewedwiththiscasual of cannabis,thispractice,considered toberelatively uncommon,wasnotrankedasanecessarily r cannabis usewasa‘normalised’behaviourandnotonewhichmetwithoutrightorunqualified r ‘deviant’ behaviour. Inthiscontext,cannabisuseemerged asastandard andacceptedfeature of much ofitsappealhingedonthesociabilityactivityandfactthatitwasnotidentifiedasa company offriendsoracquaintanceswhousedthedrug.Thestudyfoundthat“Forcannabisusers, problem forthemajorityofnon-users andalarge numberexpectedtofindthemselvesinthe striking feature ofyoungpeople’s reports. Socialisingwithcannabisuserswasnotperceived asamajor Mayock’s (2000)Dublininnercitystudyfoundthatthesocialandroutine nature ofcannabisusewasa Denmark (23%)(PompidouGroup, 2000). The largest proportion whothoughtsoare Italy(44%),theUK(34%),Slovenia(26%),Ireland (24%)and proportion sayingthatsome,most,oralloftheirfriendsusethesubstanceare expectedtobehigh. W alcohol, tobaccoandcannabisquiteroutinely, andotherdrugsoccasionally”(Parkeretal.,1998). acceptance ofawiderrangesubstancesasalternativechoicesforintoxicationor‘buzz’,including “cultural incorporationofdrugs,druguseandusersintotheireverydaylives…(and)the Parker etal.(1998)suggestthatthenormalisationofdruguseamongyoungpeopleinvolves Normalisation ofCannabisUse and manydonotappeartouseotherillicitsubstances. motivations andcontextsfortheirusagethattheyshouldnotbeseenasahomogenousgroup to haveusedotherillicitdrugs.Theauthorsconcludethatteenageheavycannabisusersdifferent use ofothersubstances,the‘ordinary’ clusterofheavycannabisuserswere lesslikelythantheothers The authorsfoundthatalthoughclearrelationships emerged betweenheavycannabisuseand belief thattheirenvironment wasstableandpredictable andthatsociety’s rulesshouldbeobeyed. The third andlargest group identifiedwere ‘ordinary’ andhadlittletodistinguishthemapartfrom a probable associationinthepublicmindwithearlier, ‘stepping-stone’theory(seealsochapter2). confusion, itissuggested,liesin awidespread misunderstanding ofthegatewaytheoryandits advocate themaintenanceofstrict cannabisprohibition and thoseopposedtoit.Thesource ofthis confusion inpublicdebateson thismatterwiththegatewaytheoryemployedbothbythose who suggests aconnectionbetweentheuseofsuchdrugsandfurther drugtaking.There appears tobe Cannabis, alongwithtobaccoandalcohol,are sometimesreferred toas‘gateway’ drugs,asresearch Gateway Effects espect. ejection. “Whileseveralrespondents referred totherisksassociatedwithprolonged and/orheavyuse outine socialevents,certainlyforusersofthedrug”(Mayock,2000,p95).Theauthorsuggeststhat ith regard to‘normalisation’,incountrieswithhighprevalence ratesforuseofcannabis, the Criminological andSociologicalConsequencesofCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 109 the user into primes . 6 Criminological and Sociological Consequences of Cannabis Use Cannabis of Consequences and Sociological Criminological Chapter 4 Chapter ecent review of the cannabis ‘gateway’ effect suggests that a more useful focus of attention should be on the that a more suggests of the cannabis ‘gateway’ effect ecent review r

common factor – drug use propensity, which leads people to use illicit drugs in the first place (Moral et al., 2002). common factor – drug use propensity, ith regards to the connection with other illicit drugs, drug takers who reported regular use of regular who reported to the connection with other illicit drugs, drug takers ith regards Once cannabis use begins, there are two principal explanations for the way in which cannabis is then two principal explanations are Once cannabis use begins, there cannabis happens to be the most easily 2001). Firstly, seen to act as a ‘gateway’ drug (Drugscope, other illicit drugs to use illicit drugs so it is generally used before available to those predisposed which almost all consistently identified as the first ‘gate’ through (although alcohol and tobacco are due to the legal status of the drug, cannabis use brings the user into illicit drug users pass). Secondly, drugs, harmful may never have met) using or selling more contact with people (who otherwise they to the legal status reference the link is explained with Here which they may then try (Drugscope, 2001). (Drugscope, 2001). cannabis surrounding and social controls W with a range of other illicit substances likely than intermittent users to experiment more cannabis are LSD and tranquillisers (Miller & Plant, 2002). Daily cannabis including inhalants, amphetamines, ecstasy, and to use alcohol and tobacco regularly, likely to be male, less well educated, to use more users are sedatives and opioids (Kandel & Davies, 1992). amphetamines, hallucinogens, psychostimulants, has supported the ‘gateway’ theory (Nutt & Nash, 2002). Australian studies suggest Recent research a sequence of drug through that adolescents who use tobacco, alcohol and cannabis tend to progress the sequence while, at the same time, increasing through use, adding new drugs as they progress also suggests that the 1998). Research & Coumarelos, drugs (Trimboll their involvement with current the use, the frequent earlier an adolescent starts using cannabis, tobacco and alcohol, and the more on Addiction and illicit drugs (National Centre the likelihood that the adolescent will use other greater found children Substance Abuse, 1994). A 21-year longitudinal study of a birth cohort of New Zealand cases use of other illicit drugs in all but three the eventual that cannabis consumption preceded & Horwood, 2000). (Fergusson most of cannabis use concluded that although into the ‘gateway’ effects research of review A recent that cannabis to other drugs, “it may be argued cannabis users did not progress 6A The ‘stepping stone’ theory held that the use of cannabis led inexorably to the use of more serious inexorably to the use of more theory held that the use of cannabis led The ‘stepping stone’ Academy of Medicine, 1944) Report (New York sixty years ago, the La Guardia illicit substances. Nearly “The use of marijuana does not lead to ‘stepping stone’ theory concluded that in consideration of the narcotics a market for these is made to create addiction and no effort or cocaine morphine or heroin of marijuana smoking”. by stimulating the practice people to start using of the substance that induced of the idea that it was the properties The rejection the so- for other explanations for the connections, hence other illicit substances has led to the search a number of risk are that there the premise theory stems from The ‘gateway’ called ‘gateway’ theory. with the young people to use cannabis and that they overlap factors and life pathways that predispose young people to use other illicit drugs life pathways that predispose taking other illicit drugs, either through a physiological mechanism or through personality and social mechanism or through a physiological taking other illicit drugs, either through 2002). The authors suggested that the factors which might explain the Laar, factors” (Rigter & Van to take risks than novelty seeking or ready that cannabis users may be more were ‘gateway’ effect, to underestimate their peers; they may have such positive experiences with cannabis that they start who have a the risk of other illicit drugs. Another hypothesis was that non-conforming adolescents into cannabis use and that, once this may be selectively recruited to use other drugs propensity markets might access to illegal then social interaction with drug using peers and greater occurred, lead to the use of other illicit drugs. 110 An Overview of Scientific and other Information on Cannabis NACD 2004 Chapter 4 out todiscos,partiesetc.than light users. et al.,2001).MillerandPlant(2002) foundthatheavycannabisusersasawholewere more likelytogo (ibid). Anotherstudyidentified early smokingandexperimentationasrisksforcannabisuse(Ellickson students whoperceive partiesasimportant,andreligion andcommunityserviceasnot important behaviours suchasbingedrinking, cigarette smokingandhaving multiplesexualpartners,andamong Cannabis usewasalsofoundtobehigheramongstudentswho participateinotherhighrisk being single,white,spendingmore timeatpartiesandsocialisingwithfriends,lessstudying. with pubsoncampus(Belletal.,1997).Studentcharacteristics associatedwithmarijuanauseincluded cannabis usefoundthatwashigheramongstudentsatnon-commuter collegesandat A studywhichexaminedthepersonalstudentbackground andcollegecharacteristicsassociated with et al.,1994). groups whileanotherAustralian studyfoundthatdailycannabisuserstendedtobemale(Hall (Trimboll &Coumarelos, 1998).Cannabisusewashighestandmostfrequent amongtheyoungerage males surveyedreported thattheyhadusedcannabiscompared withonly8percentofthefemales the respondent’s gender, age,tobacco-smokingandalcohol-drinkingbehaviour. 18percentofthe A NationalHouseholdSurveyconductedinAustraliafoundthatcannabisusewasstrongly related to Lifestyle andPersonalityFactors et al.,2001). parent withanalcoholproblem waslinkedtoearlierdruguseamongUSAadolescents(Obot and thosewhowere notsupervisedwere more likelytousedrugs(Ledouxetal.,2002).Havinga Studies havefoundthatchildren from broken families,thosewhoare dissatisfiedwiththeirparents, Family Problems problems asaresult ofthesocialcontextwithinwhichcannabisisusedandobtained. cannabis use.However, earlyusers,thestudyconcludes,maybemore vulnerabletolaterpsychosocial factors thatwere antecedent tothedecisionusecannabis,ratherthanasaconsequenceof These authorsargue thatmostoftheelevatedriskseenamongcannabisusersislikelytoarisefrom behaviours whichincrease their riskoffurthersubstanceuse,offending andunemployment. and laterpsychosocialoutcomesisthatearlyonsetcannabisuseencouragesuserstoadoptother did notusecannabisatage16.Oneexplanationprovided forthelinkagebetweenearlycannabisuse age 16hadratesoftheseoutcomesbetween2.1and19.6timeshigherthantheforthosewho unemployment subsequenttosixteen.Thosereporting usingcannabison10ormore occasionsby risks ofsubstanceuse,juvenileoffending, mentalhealthproblems, schooldrop outand The studyfoundthatearlyuse,andparticularlyfrequent use,wasassociatedwithclearincreases in onset (byage16)ofcannabisuseandlaterpsychosocialadjustment(Fergusson &Horwood, 1997). An 18-yearlongitudinalstudyofaNewZealandbirthcohortexaminedthelinkagebetweenearly Early OnsetofCannabisUse including theageofbeginninguse,familyproblems andlifestylepersonalityfactors. Some factorsthatincrease theprobability ofcannabiscausing harmfuleffects are considered here Criminological andSociologicalConsequencesofCannabisUse NACD 2004 An Overview of Scientific and other Information on Cannabis 111 . Indeed, the debate over cannabis law 7 Criminological and Sociological Consequences of Cannabis Use Cannabis of Consequences and Sociological Criminological Chapter 4 Chapter odak & Moore (2002) have carried out a cost-benefit analysis of current laws and concluded that analysis of current (2002) have carried out a cost-benefit odak & Moore Murphy (2002) criticises the prohibitionist ideology of Irish approaches to cannabis regulation; of Irish approaches ideology Murphy (2002) criticises the prohibitionist W costs outweigh benefits; Korf (2002) addresses the question of the effects of ‘coffee shops’ on cannabis use in the of ‘coffee the question of the effects Korf (2002) addresses Netherlands; Kingdom; May et al. (2002) consider the possible impact of cannabis declassification in the United Drummond (2002) questions the economic arguments for legalisation of cannabis; Drummond (2002) questions the economic arguments level of demand for the that legalisation of cannabis might well increase (2002) argues Inciardi substance; liberal cannabis laws Studies by Kilmer (2002) and Reuband (1995) suggest that countries with more rates and that levels of law enforcement do not necessarily have higher cannabis prevalence use; on cannabis appear to have no effect Bammer et al. (2002) describe the effects of the Australia initiative the ‘Cannabis Expiation Notice’, of the Australia Bammer et al. (2002) describe the effects as does Ashton (2000); For a fuller account of the various arguments see Wodak, A. et al. (2002); Inciardi, J. (2002); Levinthal, C. (2002); A. et al. (2002); Inciardi, see Wodak, For a fuller account of the various arguments (2001). P. J. (2001); MacCoun, R. and Reuter, Gray, eform remains one of the most contested areas of international drug policy. one of the most contested areas eform remains r and/or modified legislative reforms have introduced In the light of this debate, many jurisdictions in cannabis convergence practices. Within Union a greater cannabis law enforcement the European on Drugs and Drug Centre Monitoring can be identified (European laws and in their prosecution since has been a trend Legal Database on Drugs, 2001, 2002a, 2002b). There Addiction – European at or enacted legal changes directed most EU member states have proposed 2001 where and at distinguishing cannabis other drug law offenders clearly drug users from distinguishing more has Board Control illicit substances (ibid). As a consequence, the International Narcotics other from them of “undermining accusing in this area, States for legal reforms criticised some European strongly Press Board Control Narcotics (International treaties” the principle of the international drug control shops’ contravene the 1961 convention and regards states that the Dutch ‘coffee Release). The Board of the drug which would the legalisation towards the draft legislation in Switzerland as “a move 2003). Board, Control conventions” (International Narcotics contravene the international drug control in to consider this debate and the impact of these reforms It is beyond the scope of this publication as follows: are contributions some of the relevant detail. However, 7 ■ ■ ■ ■ ■ ■ ■ ■ Concerns with limiting the effects of cannabis, by implementing policies which bring about a of cannabis, by implementing policies the effects Concerns with limiting of other drugs, have combined with a number markets in for cannabis from separation in markets a review to cannabis. Demands for about a debate on the legislative approach other factors to bring and have been debated over the committees and organisations individuals and from have come from to cannabis have also met with consistent decades. Attempts to change laws relating past three a major value conflict in this area opposition and thus created Major Value Conflicts Surrounding the Conflicts Surrounding Major Value Drug Use of the 112 An Overview of Scientific and other Information on Cannabis NACD 2004 authorities shouldobtainthedrug abroad andprovide ittothepatientfree ofcharge. cannabis toalleviatesymptoms ofterminallungcancershouldbetolerated,andtherelevant medical by Italy’s banoncannabisuseinthe caseinquestion.Thejudgeruledthatthepatient’s useof ruling inVenice on13March 2002declared thattheconstitutionalrighttohealthcouldnotbe limited government andparliamentto regulate themedicinaluseof cannabisanditsderivatives.Acourt In Italy, inearly2002,theregions ofLombardy, UmbriaandTuscany requested thenational cannabis extract,tocontinueoverthree years. or otherpurposeswhichare in thepublicinterest. InMay1999,60patientsparticipatedinatrialwith In Germany, thelawstatesthatcannabiscouldbe usedonlyonthebasisofauthorisationforscientific on glaucoma.InFrance,clinicaltrialswithMarinolwere duetostartinSeptember2002. legal frameworkforclinicaltrials.Finlandiscarryingoutstudies ontheeffectiveness ofcannabinoids France andSpainconsideringthematter. InBelgium, aRoyalDecree ofJuly2001establishedthe Clinical studiesare beingundertaken inGermany, Netherlands,Finland,andthe UK,withBelgium, Monitoring Centre onDrugs andDrugAddiction–European LegalDatabaseonDrugs,2002b). manufacture, distributionand prescription ofcannabinoidsfortherapeuticpurposes(European a Directive in2001(2001/83/EC).EUmemberstatesare at different stagesintermsoftrials, legislation. TheEUlegalframeworkregarding medicinalproducts forhumanusewas codifiedby The mainEUlegislationonmedicinalcannabisandderivativesisinthesphere ofmedicinesand although usersare required tocarryidentitycards Canada hasintroduced regulations allowingpatientstoapplyforthemedicaluseofcannabis Substances Act(Newbern,2000). sanction ofUSstatelawmaystillfacethethreat offederalprosecution undertheControlled Moore, 2002).Arecent articlesuggeststhatthosewhouse cannabisformedicalpurposesunder In theUSA11jurisdictionshavevotedtopermituseofcannabisformedicalpurposes(Wodak & Medicinal CannabisandtheLaw ■ ■ ■ ■ ■ ■ Chapter 4 8 ‘Medical marijuana usersin Canadamustcarry identificationcards’. Lancet (2001)Jul21; 358(9277):220. (7308): 302; ‘Canadalegalises themedicaluse ofcannabisBritish MedicalJournal (2001)Jul14’323 (7304):68; British MedicalJournal (2001)‘Canadiandoctorsbrace themselvesascannabisbecomes legal’.Aug11;323 adverse effects. Marks (1994)argues thatthe financialcostsofcannabislawenforcement outweighsthecostofits the ‘coffee shops’intheNetherlands; Horstink Von Meyenfeldt(1996)describesthecontextofintroduction ofandtheoperation probability ofuseamongadolescents; that higherfinesandaprobability ofarrest forpossessionofcannabisdecreases the among adultsbuttheevidenceismixedforadolescents.However, Farrelly etal.(2001)suggest Pacula etal.(2000)suggestthattheimpactoffinesmayhaveanonpossessioncannabis Fahrenkrug (2000)hasexaminedtheeffect ofthenormalisation ofcannabisuseinSwitzerland; Gray’s (2001)publicationisconcernedwith‘whyourdruglawshavefailed’; data andtheassumptionthatuseofcannabisisbenign; effective. Corrigan(2001)rejects Flynn’s arguments onthebasisoflackcomparability A studybyFlynn(2000)concludesthatmeasures designedtodetercannabisusehavenot been Criminological andSociologicalConsequencesofCannabisUse 8 . NACD 2004 An Overview of Scientific and other Information on Cannabis 113 Criminological and Sociological Consequences of Cannabis Use Cannabis of Consequences and Sociological Criminological Chapter 4 Chapter esearch or other special purposes. The UK government has licensed a private company, GW other special purposes. The UK government has licensed a private company, or esearch Agency that it should authorise use of cannabis for medical ecommend to the Medical Control Conclusions number of publications encouraging with a large years The cannabis debate has intensified in recent et al., 2002). Strang et al. (2000) bemoan the (Wodak approaches debate as to the merits of different they data in policy formation. This is hampered, objective scrutiny of the available absence of careful, which have and have not changed their scale survey data in countries suggest, “by the lack of large as of the law as it is applied rather than on the effects cannabis policies, and the lack of research rational consideration of public policies authors call for a more in statute” (ibid). The expressed The only country in the EU to establish a national agency, as required by the 1961 Single Convention by the as required EU to establish a national agency, The only country in the of The Dutch Bureau on wholesale and stock is the Netherlands. Drugs, for the monopoly on Narcotics Netherlands, an amendment to the established in September 2002. In the Medicinal Cannabis was clinical trials with cannabis and prescriptions. Opium Act in 1999 allowed Norwegian Medicines Agency of Health and to the apply to the National Board Doctors in Norway can Also, doctors can unknown. are trial, although such applications a controlled for exemption to perform are if needed. Again, such exemptions in treatment apply for an exemption to use certain drugs seldom applied for. of cannabis for medicine, has not the growing The United Kingdom, although it has licensed can only be licensed for cultivation for the purpose of In the UK, cannabis established an agency. r cannabis and carry out clinical trials of a sub-lingual spray containing Pharmaceuticals, to grow medicine can prescribe due to be completed in 2004. Also, doctors cannabis extract. These trials are the Home Office. patients under licence from based on cannabis or cannabis extracts to (Ashton, 2000) stated that, in a submission to the Runciman Committee The British Home Secretary, successful, he would out by GW Pharmaceuticals prove should the medical testing being carried r clinical that, in the event of the successful completion of purposes. That committee recommended so as to the law should be changed Agency, Control trials and a positive evaluation by the Medicines “permit the use of cannabis-based medicines”. that the announced in Dáil Éireann in October 2002, the Minister for Health and Children In Ireland, had granted permission Act 1987 and 1990, of Clinical Trials under the Control Irish Medicines Board, “to trial at a hospital in Ireland conduct a clinical research to a UK-based pharmaceutical company to pain” cancer-related extract in controlling of a cannabis-based medicinal determine the effectiveness that his Department had subsequently granted further reported 2002). The Minister (Drugnet Ireland, supply and administer the cannabis- licences to the hospital to import, be in possession of, prescribe, based extract. that legalising cannabis for medicinal its critics. It has been argued is not without Reform in this area although a purposes. However, purposes is a ‘back-door’ method of legalising it for recreational finding is that number of trials appear to be showing the therapeutic benefits of cannabis, a common methods of administration for therapeutic smoking cannabis is seen to be one of the least reliable Legal Database and a high number of pollutants (European purposes, as it has a poor dosage control on Drugs, 2002b). 114 An Overview of Scientific and other Information on Cannabis NACD 2004 do withtheactualpenaltiesappliedincourtsforpossession,dealingandtrafficking offences difficult toobtainaclearpicture oftheenforcement ofcannabislawshere. Anothermajorgaphasto perspective ofenforcement, actualarrests are notreported intheofficial statisticsinIreland, thusitis significant bodyofresearch inIreland ondrugmarketsanddrug-related crime.Similarly, from the A majorgapinknowledgewhichhasbeenhighlightedthisstudyrelates totheabsenceofa Gaps inKnowledge known abouttheinfluenceofactualenforcement ofsuchlawsinEurope. their regimes” (p104).Moststudiesdonotcontrol forthe levelofenforcement ofsuchlaws.Littleis r in Europe, more attentionneededtobegivenmeasuring enforcement “ratherthantolabelling Kilmer (2002)argues thatinorder tolearnmore abouttherelationship betweenthelawanddruguse over thepastfewdecades. towards cannabisusebyadolescentsandyoungadultsinlightofthemajorincrease incannabisuse Chapter 4 9 egimes as‘liberal’or‘decriminalised’‘de-penalised’andthencomparingtheirprevalence ratesto analysis of Irishdrug-related research seeConnolly (2004). 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T ransport Research International Scientific Gill & NACD 2004 An Overview of Scientific and other Information on Cannabis 121 and reports to the Minister of State responsible for to the Minister of State responsible and reports 10 expected that the reviewer(s) would base their report(s) on an evaluation of the original base their report(s) would expected that the reviewer(s) expected that the format of the report(s) would be based on the detailed headings (attached to expected that the format of the report(s) not performance impairment. is ou are not expected to give views or opinions other than those of a scientific nature based on the than those of a scientific nature not expected to give views or opinions other ou are egard to the evidence. egard tender brief) set out in each of the Technical Annexes A,B,C and D of the EMCDDA’s “Guidelines on “Guidelines Annexes A,B,C and D of the EMCDDA’s tender brief) set out in each of the Technical Risk Assessment of New Synthetic Drugs” (ISBN - 92-9168-061-3, website http://www.emcdda.org) of natural origin. modified for use with Cannabis drugs appropriately a contract for the complete study (parts 1-4) or for may award The NACD, at its absolute discretion, as the report the contract to prepare invited to tender for therefore are each separate component. You and each of its parts must also The report a whole or to tender for each component separately. to the use of Cannabis drugs in Ireland. highlight gaps in knowledge particularly as they relate in using certain the evidence or bias inherent should also highlight any limitations of The report with or disagreement is general agreement there methodologies. It is important to specify where r Y evidence reviewed. Commission to up-to-date scientific information relating of the following areas an overview on one or more Prepare are: to be covered gaps in our knowledge. The areas on Cannabis drugs which would highlight 1. Pharmacotoxicological information; 2. on cognition, mood and mental functioning; Psychological effects 3. Sociological/criminological information; 4. physical health, mental health and dependence, Public Health risks: epidemiological information, It is on Cannabis drugs, but that they would focus medico/scientific/sociological or criminological literature listed in Appendix 1 of the tender brief. some of which are international reviews, on the many recent of information published since 1999. up to date by a consideration These would need to be brought It Background in July 2000 to advise the Committee on Drugs (NACD) was established The National Advisory of and consequences rehabilitation treatment/ prevention, to the prevalence, Government in relation findings and information. The analysis of research based on the use in Ireland, drug problem causes on the extent, nature, work programme three-year Committee is overseeing the delivery of a relevant from nominated The Committee comprises representatives of drug use in Ireland. and effects The Committee operates under the aegis of non-statutory. agencies and sectors, both statutory and Sport and Recreation the Department of Tourism, National Advisory Committee on Drugs Advisory Committee National Brief Overview – Tender Cannabis Appendix I Appendix the National Drugs Strategy. Further information can be obtained from the Department’s website the Department’s Further information can be obtained from the National Drugs Strategy. www.irlgov.ie/tourism-sport. 122 An Overview of Scientific and other Information on Cannabis NACD 2004 Appendix I T Requirements We Duration ofProject Project management Research methodology Evaluation V Email: [email protected];Web: www.nacd.ie T Ballsbridge, Dublin4 Shelbourne Road 3rd Floor, ShelbourneHouse NACD Secretary T certificate withyoursubmission. Y Closing date:4pmThursday16thMay2002 for thisproject isintheregion of The standard contractterms andconditionsare availablefrom theoffice. Thetotalbudgetavailable enderers mustsubmitawrittenproposal detailingthefollowing: el: (01)6770760/765;Fax:667 0828; enders shouldbeaddressed to: ou willberequired tosignanFOIdeclarationandyoumustincludeup-to-datetaxclearance alue formoney

administrative andtechnicalcosts. Personnel involved,theircredentials, useofconsultantsandtrackrecord; andDescriptionof Project managementfrom conceptiontocompletionwith clearmilestones; Research methodologytobeemployedandjustificationofoutputs; T Credibility ofpersonneland consultantsinvolved; Clarity indescriptionofmilestones; Ability todeliverkeyoutputsontime; Feasibility oftheapproach suggested. Understanding oftheworkinvolved; Understanding oftheproject; Best useofresources. Justification forproposed costs; Description ofcost; expect toreceive acompleteandfinalreport 3monthsfrom theaward ofthecontract. rack record. National AdvisoryCommitteeonDrugsCannabisOverview–Tender Brief of thesubmissionsbewillbasedonfollowingcriteria: € 30,000. NACD 2004 An Overview of Scientific and other Information on Cannabis 123 National Advisory Committee on Drugs Cannabis Overview – Tender Brief Tender – Overview Cannabis Drugs on Committee Advisory National Appendix I Appendix onto 1999. r ale University Press. Institute of Medicine. Washington DC 1999. Institute of Medicine. Washington National Academy Press. J. B. Grinspoon, L. and Bakalar, Y New Haven Ct. 1997. Cannabis: The Scientific and Medical Evidence. HMSO London. To 1997. New York The Lindesmith Centre, Cambridge University Press, Cambridge 1998. Toxicity; on e.g. Reproductive Mutagenicity and Carcinogenicity; Respiratory Symptoms; Dependence; Assessing the Public Health Burden. Switzerland, led by The Netherlands and Ministers’ of Public Health of Belgium, France, Germany, Rodin Foundation and the Ministry of Public Health, Belgium. Appendix 1 with Tender Document: Tender Appendix 1 with Scientific Information on Cannabis Some Recent Reviews 1. science base. Marijuana and Medicine: Assessing the 2. Marijuana: The Forbidden Medicine. 3. Agenda, 1997. A Health Perspective and Research Cannabis: Health Organisation: World 4. Committee 9th Report. Science and Technology House of Lords 5.Cannabis. of Foundation. The Health Effects Addiction Research 6. J. Marijuana Myths, Marijuana Facts: A Review of the Scientific Evidence. Zimmer L., Morgan 7. 178, February 2001. Vol. British Journal of Psychiatry. 8. Solowij N. Cannabis and Cognitive Functioning. 9. Addiction. Editorials (various) 10. initiative of the on Cannabis at the to the International Scientific Conference Report presented NOTE: TENDER RETURNS SHOULD BE MARKED: Ref: Ten/Cannabis. NOTE: TENDER RETURNS 124 An Overview of Scientific and other Information on Cannabis NACD 2004 Appendix I 2 Toxicology inanimals andpharmacology A2. information Chemical,pharmaceutical A1. Pharmacotoxicological Evidence T Appendix 2withTender Document echnical AnnexA 22 Pharmacodynamics A2.2. Pre-clinical safetydata A2.1. Routeofadministrationanddosage(e.g.oral,inhalation,intravenous, etc.) A1.4. Pharmaceuticalform(i.e.powder, capsules,tablets,liquids,injectables,cigarettes. A1.3. Legitimateusesoftheproduct A1.2. Chemicaldescription(includingmethodsofsynthesis,precursors, impuritiesifknown,type A1.1. National AdvisoryCommitteeonDrugsCannabisOverview–Tender Brief 223 Pharmacokineticsinanimals A2.2.3. 222 Invivotests A2.2.2. Invitro tests(datafrom enzyme,receptor-binding, immunomodulatoryand A2.2.1. Mutagenicandcarcinogenic potential A2.1.5. Embryo-foetalandperinataltoxicity A2.1.4. Reproduction function A2.1.3. Repeated-dosetoxicity A2.1.2. Single-dosetoxicity A2.1.1. Any distinctivemarkings,logos,etc.tobenoted) and level) ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ hormonal tests) Behavioural studies Effects onliver, kidneys, genito-urinarysystem Effects ongastrointestinal system Effects onrespiratory system Effects oncardiovascular system Effects oncentralnervoussystem Pharmacokinetic interactions Excretion (includingeliminationhalf-life) Metabolism (includingmajormetabolisingenzymesandmetabolites) Distribution Absorption NACD 2004 An Overview of Scientific and other Information on Cannabis 125 National Advisory Committee on Drugs Cannabis Overview – Tender Brief Tender – Overview Cannabis Drugs on Committee Advisory National Appendix I Appendix instruments, rating scales) psychiatric assessment) instruments, rating scales) psychiatric assessment) A4.2.1. Tolerance symptoms A4.2.2. Abstinence behaviour A4.2.3. Drug-seeking A3.1.1.effects and behaviour on cognition Effects A3.1.2. Cardiovascular effects A3.1.3. Respiratory effects A3.1.4. Gastrointestinal A3.1.5. system kidneys, genito-urinary on liver, Effects A3.1.6. on immune system Effects A3.1.7. and medicines Interactions with other drugs A3.1.8. on ability to drive and use machinery Effects A3.1.9. of overdose Effects A3.2.1. Absorption A3.2.2. Distribution A3.2.3. enzymes and metabolites) Metabolism (including major metabolising A3.2.4. (including elimination half-life) Excretion A3.2.5. Pharmacokinetic interactions B2.4. status/psychiatric comorbidity (psychological and on psychopathological Effects B2.1. assessment) (neuropsychological on cognitive functioning Effects B2.2. (multifactorial intelligence tests) on intelligence Effects B2.3. on emotional status, behavioural patterns and personality (psychological Effects B1.4. status/psychiatric comorbidity (psychological and on psychopathological Effects B1.1. assessment) (neuropsychological on cognitive functioning Effects B1.2. (multifactorial intelligence tests) on intelligence Effects B1.3. on emotional status, behavioural patterns and personality (psychological Effects A4.3. Clinical safety A4.1. users Studies on street A4.2. Dependence potential in humans A3.2. Pharmacokinetics in humans A3.1. in volunteers Laboratory studies echnical Annex B B2. effects Chronic Psychological Risk Assessment (cognition, mood and mental functioning) B1. Acute effects T A4. Clinical experience A4. Clinical A3. pharmacology Human 126 An Overview of Scientific and other Information on Cannabis NACD 2004 6 Socialfactorsthatincrease theprobability ofharm C6. Theretail market C5. Wholesaleproduction anddistribution C4. Appendix I 3 Othersocialconsequences C3. Consequencesonthesocialbehaviour oftheuser C2. Socialconsequencesfortheuser C1. Sociological/Criminological Evidence T Psychologicalfactorsthatincrease (e.g.,moodandanxiety theprobability ofharm B4. Psychologicaleffects ofdrug-using careers B3. echnical AnnexC C5.5. Entrepreneurial criminalsuppliers C5.5. publicorderViolence, and nuisanceimplicationsoftheretail market C5.4. Existence andcharacteristicsofstreet markets C5.3. Semi-public subculturalconsumptionmarket(discos,etc.) C5.2. Non-commercial ‘private’consumptionmarketamongusers C5.1. Involvement of(international)organised crime C4.3. C4.2. Money-laundering aspects inconnectionwithwholesaleproductionViolence anddistribution C4.1. C3.2. Implications forsocialinstitutions(school,labour, recreational,C3.2. etc.)andcommunity Presence orabsenceofmajorvalueconflictssurrounding theuseofdrug C3.1. Drug-related traffic offences C2.4. Drug-related violence C2.3. Drug-related acquisitivecrime C2.2. Drug-related disorderly conduct C2.1. C1.3. Marginalisation Educationandemploymentproblems C1.2. Primary relations and/orfamilyproblems C1.1. conditions leadingtoself-medication,sensationseeking) National AdvisoryCommitteeonDrugsCannabisOverview–Tender Brief services NACD 2004 An Overview of Scientific and other Information on Cannabis 127 National Advisory Committee on Drugs Cannabis Overview – Tender Brief Tender – Overview Cannabis Drugs on Committee Advisory National Appendix I Appendix D1.1. at consumer level (extent/quantities) Availability D1.2. (at consumer level) Sources in availability D1.3. Trends of variability dose and degree D1.4. Average of adulterants D1.5. Purity levels and presence D1.6. Other active ingredients prices and range D1.7. Typical D2.1. of scientific information on product Availability D2.2. of product of information on effects Availability D2.3. amongst drug consumers in general product of Level of awareness D2.4. among consumers of product and perceptions effects Level of knowledge of product, population D2.5. General D3.1. Extent of use of product D3.2. of use Frequency D3.3. Route(s) of administration D3.4. Other drugs in combination with product D3.5. Geographical distribution of use and patterns of use in prevalence D3.6. Trends D4.1. of users Age and gender D4.2. available/used product where Social groups D4.3. associated with use Risk behaviours D4.4. about vulnerable groups Special concerns users in characteristics/behaviours of D4.5. Trends emergencies D5.1. Hospital D5.2. and indirect) Deaths (direct accidents D5.3. Traffic D5.4. treatment/counselling Requests for D5.5. indicators Other health D6.1. and rituals of consumption Risk factors linked to circumstances echnical Annex D D2. and availability of information Knowledge, perceptions D3. and patterns Prevalence of use D4. Characteristics and behaviour of users D5. Indicators of health consequences D6. Context of use D7. Implications for the non-using population Public Health Risks: Epidemiological Evidence Public Health Risks: Epidemiological D1. the market on and quality of product Availability T 128 An Overview of Scientific and other Information on Cannabis NACD 2004 Sub CommitteeofNACDasJune2004 Members oftheConsequences Appendix II Mr Tony Geoghegan,IAAAC Mr JohnKelly, DeptofCommunity, RuralandGaeltachtAffairs Mr BarryO’Connor, DeptofJustice,EqualityandLawReform Dr DesmondCorrigan,SchoolofPharmacy, Trinity College Dr EamonKeenan,ConsultantPsychiatrist Dr DervalHowley, NDST Supt FinbarrO’Brien,Garda NationalDrugUnit Dr HamishSinclair, DMRD Dr MaryEllenMcCann,Voluntary DrugTreatment Network Members Ms AnnaQuigley, Citywide Chairperson NACD 2004 An Overview of Scientific and other Information on Cannabis 129 eatment Eamon Keenan Dr ice Chairperson NACD Membership as of June 2004 of June as Membership NACD Chairperson College Trinity of Pharmacy, Dr Des Corrigan, School V Network Drug Treatment Voluntary Dr Mary Ellen McCann, Members Eastern Regional Health Authority Dr Joe Barry, Mr Willie Board Collins, Southern Health & Addiction Counsellors Geoghegan, Irish Association of Alcohol Mr Tony National Drugs Strategy Team Dr Derval Howley, Eastern Regional Health Authority Dr Eamon Keenan, Consultant Psychiatrist & Children Department of Health Mr David Moloney, National Drugs Unit Supt Barry O’Brien, Garda Mr Liam O’Brien, Community Sector Department of Justice, Equality & Law Reform Mr Barry O’Connor, & Science Dr Máirín O’ Sullivan, Department of Education Community Sector Ms Anna Quigley, Board Division, Health Research Drug Misuse Research Dr Hamish Sinclair, Rural & Gaeltacht Affairs of Community, Ms Kathleen Stack, Drugs Strategy Unit, Department Chairpersons of the sub-committees Consequences TrendsEarly Warning/Emerging Prevalence Mr David Moloney PreventionTr Ms Anna Quigley Dr Des Corrigan Dr Mary Ellen McCann Appendix III Appendix 130 An Overview of Scientific and other Information on Cannabis NACD 2004 NACD 2004 An Overview of Scientific and other Information on Cannabis 131 132 An Overview of Scientific and other Information on Cannabis NACD 2004