Short Title CHRONIC HEAVY USE OF CANNABIS: PSYCHOLOGICAL EFFECTS '- Ph.D. PSYCHOLOGY CHRONIC HEAVY USE OF CANNABIS SATIVA: PSYCHOLOGICAL EFFECTS Marilyn Bowman Abstract The psychological effects of chronic heavy use of Cannabis Sativa (marijuana) were studied in a population of normal adult males with a history of heavy daily use for ten years. Three groups of objective·psychological tests were used to compare these subjects with a control group matched for age, sex, social class, alcohol use, intelligence, education and 'modernity'. The first group of tests were concerned with physiological, sensory and perceptual-motor functions; group two tests measured concept-formation and abstracting abilities, and the third group of tests measured memory functioning. An initial study demonstrated that there were no indica- tions of user-impairment on the se measures. A replication of the study using an improved single-blind design confirmed the findings of the original study. It is suggested that this drug does not lead to mental impairment comparable to that found typical of alcohol or cocaine-abusing subjects. CHRONIC HEAVY USE OF CANNABIS SATIVA: PSYCHOLOGICAL EFFECTS by Mari1yn Laura Bowman A thesis submitted to the Facu1ty of Graduate Studies and Research in partial fu1fi11ment of the requirements for the degree of Doctor of Phi1osophy. Department of Psycho1ogy McGi11 University March, 1972 Montreal, Canada ® Marilyn Laura Bowman 10/72 ACKNOWLEDGEMENTS I wish to thank Dr. R. O. Pihl for advice and encourage­ ment throughout the course of my research. In addition, I thank my Jamaican friends Ronald Watts and Jennifer Lynn, without whose help this study could not have been done. A modest grant from the American Psychological Association is also gratefully acknowledged. Joe Vanagas and Laurel Ward are thanked for their helpful technical assistance. TABLE OF CONTENTS 1 Page INTRODUCT ION 1 History and Incidence of Use 1 The Chemistry and Pharmacology 3 Studies of Immediate Effects in AnimaIs 6 Studies of Chronic Effects in AnimaIs 13 Reports and Studies of Immediate Effects in Humans 17 Reports and Studies of Chronic Effects in Humans 29 Studies of Cannabis Users 37 Some Basic Issues in Human Drug Research 44 THE PRESENT INVESTIGATION 48 Subjects 48 Measures 53 Study I -- Method 71 Results 74 Discussion 80 Study II Method 89 Results 90 Discussion 96 DISCUSSION 103 SŒ-1MARY 121 REFERENCES 122 APPENDICES l INTRODUCTION History and Incidence of Use Marijuana preparations are the most widely used illicit drugs in the world, having an estimated 200 to 300 million consumers (Mechou1am, 1970). Until quite recent1y the vast majority of users were found in Oriental and African cultures. This pattern is now shifting and in western techno1ogica1 societies there has been a major increase in the number of users. This increase appears to represent an ongoing trend and has brought the use of the drug under renewed scrutiny by governmental and hea1th authorities who have long maintained strict sanctions against its use. One of the basic unresolved issues concerning the drug is the extent and manner in which prolonged regular use might change the user, either in terms of inte1lectual performance or in terms of persona1ity and social functioning o This thesis will attempt to answer some of the questions relating to inte1lectua1 performance changes with chronic heavy use of the drug. Initial1y the incidence rates and patterns of use of the drug will be described in order to place the issue into its current social contexte A description of the drug in terms of its chemistry, its active e1ements and genera1 potency will fo11ow. These findings will be used 1ater in the study to provide a background against which data from the investigation may be evaluated. 2 In order to describe the dimensions of the use of the drug in western societies it is interesting to review some of the studies of the incidence of use found in Britain, the United States, and Canada. In Britain Bewley (1966) drew attention to the changing incidence rates reflected in the statistics describing Can­ nabis offenses; these ranged from a figure of 100 in 1945 to more than 800 by 1964. North American studies have used sophisticated survey techniques in attempting to establish incidence rates. Man­ heimer, Me1linger and Balter (1969), in such a study among San Francisco adults which specifically excluded students, found that 13% of his sample had used the drug at least once, with certain age groups demonstrating significantly higher rates than that: men aged 18-24 had a 50% incidence rate. In general a consistently high incidence rate has been found among young adult men. Studies of soldiers in Vietnam have found usage rates around 30% (Sapol & Roffman, 1969; Colback, 1971), which is a rate typically found also in studies of civilian co1lege men. The Preliminary Report of the National Commission on Marijuana and Drug Abuse (to the United States Governrnent) estimated that 24 million Americans have tried the drug at least once, while 8.3 million appear to be fairly steady consurners (Shafer, 1972). In Canada, a study of the figureô of the Division of Narcotics Control for cannabis-related cha~ges, shows the 3 fo11owing trend: In 1962 there were 24 cases; in 1969 this figure had risen to 5,157 (Addiction Research Foundation, 1969). Individua1 surveys re1ating to incidence of use in schoo1s and co11eges across Canada give figures ranging from 5.9% to 24% in 1969 (LeDain, 1970); figures for use by adu1ts on the who1e have not yet been satisfactori1y estab1ished. If current rates of experimenting with the drug continue one author predicts that within six years aIl students in metro­ po1itan Toronto schoo1s will have tried the drug (Smart, Fejer, & White, 1971). Thus British and Canadian studies revea1 an increasing use of the drug, whi1e the American studies have shown rela­ tive rates of use in the genera1 population which are now quite high. The 1ega1 sanctions against the drug are coming underincreasing attack and the three governments described above have each been stimu1ated to review the evidence con­ cerning the effects of its use. (In Britain the Wootton Committee, the American Committee noted above, and in Canada, the LeDain Commission.) The data to be provided in this in­ vestigation represent a contribution of direct relevance to the concerns of these committees, and to the general public. The Chemistry and Pharmaco1ogy One of the reasons for the dearth of information con­ cerning effects of the drug has been an extreme1y 1imited scientific 1itcrature. This 1ack of investigations had had two main roots. First1y, 1ega1 strictures concerning pos­ session have been enforced against scientific investigators 4 in the same manner as against potentia1 consumers, thus the drug was not rea11y accessible for research purposes until quite recent1y. Second1y, unti1 eight years ago the actua1 chemistry and pharmaco1ogica1 activity of the cannabinoids were 1arge1y unknown and thus the question of dosage uncon­ tro11ed. Previous1y, attempts made to extract and identify the main active compounds in marijuana had resu1ted in the des­ cription of cannabino1 (CBN), cannabidio1 (CBD) and tetra­ hydrocannabino1 (THC) as the major ingredients of interest (Adams, 1940). Adams suggested that THC was the principal active ingredient, a1though he was unab1e to describe its chemica1 structure (a task he had accomp1ished for CBN and CBD). In addition he noted the effects of the passage of time on these agents, in particu1ar the transforming of CBD to THC and then to CBN. This sequence has been recent1y confirmed and described in detai1 (Gr1ic, 1968). It appears that the resin in green plants is main1y CBD acid which changes to CBD as ripening progresses, then to ~8THC and A9THC when the plant is mature. In the past decade considerable work has been done to confirm, describe and synthesize THC in its various isomers (Gershon, 1970) and as a resu1t of the se studies there has deve10ped a minor 'controversy concerning whether .D8THC or D.9THC is the principal active THC isomer ( Taylor, Lenard, & Schvo, 1965; Garriott, Forney, Hughes, & Richards, 1968). In an important study (Isbe11, Gorodetsky, Jasinski, C1aussen, 5 Spulak, & Korte, 1967) it was demonstrated that a synthetic Â9THC used by human subjects in both oral and smoked pre­ parations~ produced those subjective effects typical of mari­ juana. However a number of investigators have shown that ~THC appears to convert to ~8THC with ageing of the plant, with exposure to acids or with combustion or high temperatures (Lerner & Jeffert, 1968; Bfron, 1967). On this basis it is claimed that ~8 could weIl be the actual active ingredient within the body under either oral or smoked routes of admini­ stration. In spite of this issue Â9THC is commonly recognized . as the principal psycho active isomer and is the element most commonly used to describe the potencies of various prepara­ tions of marijuana used in contemporary studies. As a result of newly gained freedom to study the drug and increasing knowledge of its chemical identity, studies have attempted to describe the nature of its action within the body, i.e., the pharmacology of the drug. It has been frequently noted that a higher level of mari­ juana activity is experienced from smoking than from oral ingestion of equivalent doses (Isbell, et al., 1967; Mechoulam, 1970). This has been explained as being due to the conversion of inactive THC acids into ~9THC with the heat of combustion. Once in the body it has not been clearly established whether the psychoactivity is caused by ~9THC, ~8THC or metabolites created within the body. The frequent report that no effects are experienced the first time the drug is used, would support 6 the hypothesis that metabolites are the actual active ingre­ dients.