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 Information of Scientific and other An Overview 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 Authors: An Overview of Scientific and other Information on Cannabis Claire Collins Johnny Connolly Dominique Crowley Mark Morgan September 2004 Editor: Mark Morgan 1 Dublin Published by the Stationery Office. NACD 2004 To be purchased directly from the Government Publications Sales Office, Sun Alliance House, Molesworth Street, Dublin 2, or by mail order from Government Publications, Postal Trade Section, 4-5 Harcourt Road, Dublin 2, (Tel: 01-6476834/35/36/37; Fax: 01-4752760). 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Le ceannach díreach ón Oifig Dhíolta Foilseachán Rialtais, Teach Sun Alliance, Sráid Theach Laighean, Baile Átha Cliath 2, nó tríd an bpost ó Foilseacháin Rialtais, an Rannóg Post-Tráchta, 4-5 Bóthar Fhaearchair, Baile Átha Cliath 2, (Teil: 01-6476834/35/36/37; Fax 01-4752760). © National Advisory Committee on Drugs 2004 Designed by first impression An Overview of Scientific and other Information on Cannabis 2 NACD 2004 Table of Contents Biographies 5 Foreword – Minister of State 6 Foreword – Chairperson NACD 7 Executive Summary – Authors 8 Chapter 1: The Pharmacological and Toxicological Effects of Cannabis Dr Dominique Crowley Overview 18 Chemical and Pharmaceutical Information 18 Human Pharmacology 26 An Overview of Scientific and other Information on Cannabis Pharmacokinetics in Humans 27 Clinical Experience 29 Cannabis Use and Epilepsy 35 Dependence Potential in Humans 39 Conclusions 41 Gaps in Knowledge 41 Chapter 2: Public Health Risks of Cannabis Use: Epidemiological Evidence Dr Claire Collins Overview 51 Availability and Quality of Product on the Market 51 Knowledge, Perceptions and Availability of Information 54 Prevalence and Patterns of Use 57 Characteristics and Behaviours of Users 64 Indicators of Health Consequences 68 Context of Use 72 Conclusions 73 Gaps in Knowledge 73 Chapter 3: Psychological Consequences of Cannabis Use Dr Mark Morgan Overview 79 Cannabis and Cognitive Performance 79 Cannabis and Self-injurious Behaviour 82 Cannabis and Perception of Physical Health 84 Cannabis Use and Educational Outcomes 85 Cannabis Use and Occupational Performance 87 Psycho-social Consequences of Cannabis Use 88 Perceptions of the Risks of Cannabis Use 90 3 Conclusions 91 Gaps in Knowledge 92 NACD 2004 Chapter 4: Criminological and Sociological Consequences of Cannabis Use Mr Johnny Connolly Overview 97 Legislation on Cannabis in Ireland 97 Social Consequences for the User 99 Consequences on the Social Behaviour of the User 100 The Cannabis Market 104 Social Factors that Increase the Probability of Harm 107 Major Value Conflicts Surrounding the Use of the Drug 111 Conclusions 113 Gaps in Knowledge 114 Appendices: Appendix I: National Advisory Committee on Drugs Cannabis Overview – Tender Brief 121 Scientific Information on Cannabis 123 Technical Annexes of Risk Assessment Guidelines 124 Appendix II: Members of Consequences Sub Committee of NACD 128 Appendix III: Members of NACD as of June 2004 129 List of Tables: Table 1. Properties of Some Natural Cannabinoids 19 Table 2. Forms of Cannabis 22 Table 3. Summary of the Effects of Cannabinoids 26 An Overview of Scientific and other Information on Cannabis Table 4. Prevalence Rates of Cannabis Consumption in the 63 General Population of Western Nations Table 5. ESPAD (1999) Study: Association of Cannabis, 89 Cigarette and Alcohol Use with Anti-social Behaviour Table 6. ESPAD (1999) Study: Association of Cannabis, 90 Cigarette and Alcohol Use with Victimisation Table 7. ESPAD (1999) Study: Perceived Risk of Substance Use 91 4 NACD 2004 Biographies Dr Claire Collins PhD, MSocSc, BSocSc, DipStats Dr Collins is the Research Director of Social and Clinical Research Consultants (SCRC). Her background is in medical sociology, statistics, public health and epidemiology. Her recent research has been in the areas of health services research and public health, in collaboration with both public and private organisations. She is also the Statistician in the Rotunda Hospital and the Director of Research for the Irish College of General Practitioners. Mr Johnny Connolly BA (Mod) LDIP LLM Johnny Connolly is a Criminologist. He is employed as a Research Officer with the Drug Misuse Research Division of the Health Research Board. His current research interests include: drug markets, the relationship between drug use and crime, community policing and non-custodial sanctions. An Overview of Scientific and other Information on Cannabis Dr Dominique Crowley MB, BCh, BAO, MPH, FFPHMI, MFPHM, Dip Med Tox Dr Crowley is a Specialist in Public Health Medicine in Ireland. Her recent research has been in the areas of environmental public health, risk assessment and risk communication. She is a member of the National Forum on Fluoridation, representing the Office of the Chief Medical Officer in the Department of Health, and is also a member of the FSAI Scientific Sub-Committee on contaminants and additives. Dr Mark Morgan NT, MSc, PhD Dr Mark Morgan is Head of the Education Department at St. Patrick’s College, Drumcondra, Dublin, Ireland. His research has mainly been in the areas of literacy, educational disadvantage and substance use, particularly the evaluation of prevention programmes. 5 Foreword – Minister of State NACD 2004 I am happy to welcome this overview of the available information on the effects of cannabis use. The report is primarily concerned with the consequences of cannabis use for the individual and society in terms of the physical, psychological, educational and mental health consequences, as well as implications for public health for society and for law enforcement. As the overview notes, cannabis is the most widely used illegal drug in Ireland. Knowing as much as possible about its health and social consequences is, therefore, essential. In recognition of this, the Government asked the National Advisory Committee on Drugs (NACD) to undertake this research in order to improve our overall knowledge in this area As the report points out, the vast body of research on the consequences of cannabis use does not lend itself to simple and easy conclusions. However, the report provides an invaluable service in bringing together the available evidence and drawing conclusions, where possible. I believe the report shows that cannabis is a complex substance and, notwithstanding the fact that it is not as dangerous as some other drugs, it can have many damaging effects on the physical and mental health of the user, particularly the young and those who are heavy users of the drug. The consequences of much wider use of cannabis on the health of the general population have to be considered by those who advocate such a move. The approach we have adopted in Ireland is, I believe, appropriate for our circumstances and our society and we have to refute the notion promoted by some that cannabis is harmless. As I have said on many occasions, I am always grateful for the research and analysis provided by the NACD and for all the on-going work of all of the members of the National Advisory Committee on Drugs, in particular, its Chairperson - Dr Des Corrigan, its Director - Ms Mairéad Lyons and its Research Officer - Ms Aileen O’Gorman. Finally, I would like to congratulate the authors Claire Collins, Johnny Connolly, Dominique Crowley and Mark Morgan, who also served as editor, on this excellent and comprehensive report. Noel Ahern TD Minister of State with responsibility for the National Drug Strategy An Overview of Scientific and other Information on Cannabis 6 NACD 2004 Foreword – Chairperson NACD We know from our general population survey that Cannabis drugs are the most widely used of the illegal drugs in Ireland. This report on the scientific evidence about the drugs produced from the Cannabis plant also demonstrates that they are among the most complex consumed by human beings. This complexity extends from the chemical mixture produced by the plant through the diversity of their effects on so many different parts of the human body. The varied pharmacological and psychological effects of Cannabis drugs give them a unique place in any listing of psychoactive drugs. Not only are the drugs and their effects difficult to categorise, there are also many individual and societal factors which interplay with them and influence their impact on those who use them and on the broader community. Dr Mark Morgan and his co-contributors Claire Collins, Johnny Connolly and Dominique Crowley have done a remarkable job in capturing the complexities of the Cannabis drugs in all their manifestations. The NACD is grateful to them for performing such a mammoth task and in particular for highlighting An Overview of Scientific and other Information on Cannabis broader gaps in our knowledge of these drugs. The authors have also pinpointed more specific areas where we in Ireland need to improve our information base relating to Cannabis. It is noteworthy that many of the broader areas to which attention is drawn in this report are similar to those mentioned in a Draft Resolution on Cannabis being debated at present at EU level. For instance, the Resolution refers to the need for research on Cannabis within the EU’s Sixth Framework Programme especially regarding dependency and health risks and calls on the EMCDDA, as the EU’s Drugs Agency to analyse how changes in those using Cannabis intensively and/or in high dose are reflected in the number of people experiencing problems and/or becoming dependent. With respect to areas where national work is necessary, some of the points noted in the report are addressed by the detailed analysis of Cannabis use in Ireland published as Bulletin 3 of the NACD’s general population survey.