141. Cannabis sativa is an herbaceous annual plant which readily grows untended in temperate climates in many areas of the world, including Canada. Although there are several varieties (i.e. indica, americana, and africana) most botanists consider these to be members of the same species. Indian hemp, as this plant is sometimes known, has separate male and female forms and may grow to 10 to 12 feet under favourable conditions.

 The first detailed description of cannabis available today appeared in a medicinal book prepared by the Chinese Emperor Shen Nung around 2737 B.C. Since then, cannabis has been known in the East by such descriptions as 'the heavenly guide', 'Poor man's heaven', 'soother of grief' and, in a more moralistic tone, 'the liberator of sin'.223 A United Nations' report 20 years ago estimated that 200 million people in the world used the drug for medical, religious or recreational purposes.

 142. What is commonly referred to as marijuana ('grass', 'pot', 'weed', 'tea', 'boo' or 'Mary Jane') in North America is usually made up of crushed cannabis leaves, flowers, and often twigs, and may vary considerably in potency from one sample to another. Similar preparations are known as bhang and the more potent ganja in India, kif in Morocco and dagga in Africa, while the relatively pure resin is called hashish ('hash') in the West and much of the Middle East, and charas in India. Hashish is usually prepared by pressing or scraping the sticky amber resin from the plant, and may be more than five times as potent on a weight basis as high quality marijuana. In addition to these common forms, concentrated cannabis extract is available in some countries in an alcohol solution (tincture of Cannabis) designed for medical purposes (e.g., British Pharmacopoeia).

 The various forms of the drug are frequently listed under the general term cannabis since they differ primarily in the degree of potency. It must be stressed, however; that differences in the preparation, quantities involved, mode of administration and patterns of use are also important determinants of effect, and it is often essential that these factors be identified in the examination of individual reports.

 143. In many societies, cannabis sativa has been a highly valued crop. The trunk fibres of the woody plant are used in the reduction of hemp rope and twine; the seeds are a source of a product similar to linseed oil and, until recently, were also commonly used as bird food; the pharmacological properties of the leaves, flowers and resin have been used for thousands of years, for both medical and non-medical purposes.

 Cannabis was apparently brought to the Western hemisphere in the sixteenth century by the Spaniards and was an important fibre and seed crop centuries later in the British colonies of North America. A portion of George Washington's Mount Vernon plantation was dedicated to the cultivation of hemp and it was reported that, 'Virginia awarded bounties for hemp culture and manufacture, and imposed penalties on those who did not produce it.'31 Although there are conflicting opinions, it would appear that the psychotropic properties of cannabis may have been little known to the colonial farmers at that time.12,120 Hemp was again cultivated in North America during World War II after the major supply lines from the East were cut off. These plants were apparently selected for high fibre content and low pharmacological activity.

 144. When grown under optimal conditions almost all parts of both male and females plants, may be potentially psychoactive. The female has traditionally been considered the more efficient producer of the resin responsible for the pharmacological effects, although recent studies question this conclusion.235 Female flowers, prior to pollination, contain the greatest concentration of resin and, consequently, the flowering tops are highly valued and are frequently prepared separately from the remainder of the plant. The potency is further affected by the climate and soil conditions, certain genetic factors, and the time and method of harvesting and preparation.

 145. In recent years, the chemistry of cannabis has come under careful investigation. Although numerous cannabinols were considered potential candidates in the search for the active principles of cannabis, it appears that certain forms of tetrahydrocannabinol (THC) are the most potent psychoactive constituents. Several of these have recently been isolated and synthesized.155 It would be incorrect to say, however, that the active ingredient in cannabis has been established, since much basic psychopharmacological work remains to be done in this area. Several related synthetics (Synhexyl* or Pyrahexyl*) have also been investigated. Although there are continual reports of THC being sold on the illicit market, samples alleged to be THC have invariably been found to be some other drug.

 146. Frequent cases of cannabis use first came to the regular attention of government and public health officials in North America after World War I, although earlier references to such use exist. This increase was correlated with an influx of Mexican workers into the Southern United States, and subsequent use was apparently largely confined to ethnic minority groups, with a high proportion of urban-dwelling Afro- and Spanish-Americans among the known users. In addition, cannabis use was often noted among musicians and others in the fields of entertainment and creative arts. In the last decade, however, the use of cannabis has spread to quite a different segment of the population and appears to be most prevalent among, although by no means restricted to, middle-class youth of high school and college age. In spite of the risk of severe penalties, estimates based on a variety of sources suggest that eight to 20 million North Americans have at least tried cannabis.260 These figures must be considered tenuous however, since there is no satisfactory way to assess their validity.

 147. Recently the controversy surrounding this drug has reached epidemic proportions. Usually reliable authorities have publicly taken diametrically opposed positions regarding cannabis, not only on moral and social policy issues, but on the supposedly 'hard' scientific facts as well. Although the current world literature on cannabis numbers some 2,000 publications, few of these papers meet modern standards of scientific investigation. They are often ill-documented and ambiguous, emotion-laden and incredibly biased, and can, in general, be relied upon for very little valid information. Scientific expertise in the area of cannabis is limited by the simple fact that there is little clearly-established scientific information available, and preconceived notions often dominate the interpretation of ambiguous data. The resulting confusion is exemplified by current legislation in many parts of the world, including Canada and the United States, which classifies cannabis with the opiate narcotics, even though these drugs are pharmacologically different.

 This rather sorry state of affairs can be attributed to several factors. To begin with, governmental restrictions on the medical and scientific use of cannabis in North America have been so strict over the past few decades that the majority of would-be researchers have found it more attractive to work in other areas. Secondly, since the widespread use of cannabis in North America is a relatively new phenomenon, it has not, in the past, been considered a particularly high priority research area from a public health standpoint. In addition, until recently, there was little possibility of standardizing the cannabis substances being studied, since little was known about the relevant aspects of cannabis chemistry. Consequently, there was little basis for comparing reports, and generalizations were limited. To date, no authorized experimental research of cannabis effects on humans is being conducted in Canada.

 The observations collected during centuries of relatively unrestricted cannabis use in regions of the East have rarely been scientifically documented because most of what we consider modern science has been, until recently, basically a Western phenomenon. Furthermore, profound cultural, moral and legal differences complicate the problem of extrapolating from reports of Eastern usage to the North American scene.

 While there has been a concerted effort, in the following discussions of cannabis effects, to concentrate attention on fairly well documented topics and to avoid areas where the evidence is especially weak, the scanty nature of our current scientific knowledge of cannabis necessitates a cautious and tentative approach to this interim review.

 148. There is no currently accepted medical use of cannabis in North America outside of an experimental context. Although cannabis has been reported to produce an array of possibly useful medical effects, these have either not been adequately investigated, or can be replaced by using other more readily available and convenient drugs. The natural product's variability in potency and instability over time are among the factors which have led to its disfavour in Western 20th century medicine. However, recent advances in isolation and synthesis of certain active principles of cannabis have prompted a second look at some of the potentially therapeutic aspects of the drug.159

 Cannabis has been used in the past, is presently used in some cultures, or is currently under clinical investigation, for its alleged anxiety-reducing, tranquillizing, mood-elevating, appetite stimulating, analgesic (pain reducing) and anti-bacterial effects. It has also been used to reduce fatigue or insomnia (sleeplessness), to ease opiate narcotic withdrawal, and as an aid to psychotherapy in applications analogous to psycholytic LSD therapy or as a clinical antidepressant. In addition, cannabis has often been employed in the past, and is currently used illicitly in North America, to reduce the secondary symptoms and suffering caused by the flu and the common cold. These various alleged therapeutic properties of cannabis have not been adequately studied in a scientific context, and their general medical potential remains a matter of conjecture.

 149. Marijuana is usually smoked in hand-rolled cigarettes known as 'joints', 'J's', 'sticks' or 'reefers', the butt of which is often called a 'roach'. Normally one or two joints is sufficient to produce a mild 'high', although this varies considerably according to individual factors and the potency of the sample. Hashish may vary in colour from very light to dark-brown and ranges from a hard waxy substance to a crumbly, powdery consistency. Small pieces of hashish may be placed on the tip of a burning tobacco cigarette and the smoke inhaled off the top. Ordinary pipes, water pipes (hookahs) and a variety of specially made instruments are also employed in the smoking of hashish and marijuana.

 In the Middle East and Far East cannabis is often mixed with such substances as datura stramonium (Jimson weed), tobacco, nux vomica, and opium, which further complicates the interpretation of reports from these areas.107 Samples of cannabis obtained in Canada generally do not contain other drugs, although they may be 'cut' with relatively inert substances.143 There have been no analytical reports to support rumours that heroin or other opiate narcotics have been found in cannabis in this country.

 150. Cannabis smoke is usually inhaled deep into the lungs and held there for an extended time, in order to increase absorption. The onset of psychological effects is almost immediate with the smoking of more potent forms of cannabis, and the peak effects usually occur within the first quarter-hour following inhalations. Major effects usually last several hours while milder ones may endure for half a day longer.

 Absorption by the gastro-intestinal tract is effective, although relatively slow. Since the resin is fairly soluble in hot water, cannabis is often used in making tea or other beverages - mild bhang drinks, for example, are common in India. In some countries hashish is incorporated into buttered candies called majoon, or other foods. The effects of cannabis taken orally usually begin after an hour or so, and gradually reach a peak within several hours, then slowly decline. Very high doses may produce some effects lasting more than a day, although the drug is not ordinarily used in such large quantities in North America. The effects of oral administration are often noticeably different from those of inhalation. It is uncertain whether this is due to chemical changes from the heat in the smoked material, effects of the digestive juices or other metabolic enzymes after oral administration, or differences in rapidity and efficiency of absorption and distribution in the two methods. On a weight basis, however, smoking seems to be the most effective mode of administration. The speed of acquisition, the duration of effects, and the recovery from the cannabis 'high' depends on the rate, quantity, and mode of administration, in addition to various psychological and physiological characteristics of the user.

 151. While considerable progress is being made in this area, little is known at the present time regarding the metabolism, excretion, and mechanism of action of cannabis. There is evidence that some metabolites of THC are psychoactive. Techniques are being developed which are designed to measure cannabis products in the urine, blood and saliva, and substantial breakthroughs are expected in these areas in the near future.

 152. Although the literature is brimming with impressionistic reports of the effects of cannabis, only a small number of these meet even the most rudimentary scientific standards. A review of those effects which have been unequivocally established and scientifically documented would be a scant summary indeed. In spite of strong disagreement among extremists on many points in the cannabis controversy, major governmental reports by independent- commissions of various backgrounds over three-quarters of a century have come to some surprisingly similar conclusions regarding the use of cannabis. Such reports include the British Indian Hemp Drugs Commission Report (1893-4),107 Mayor La Guardia's Report on The Marijuana Problem in The City of New York (1944),149 the United States President's Commission on Law Enforcement and Administration of Justice: Task Force on Narcotics and Drug Abuse (1967),220 and the Cannabis report (1968), by the British Advisory Committee on Drug Dependence, prepared under the chairmanship of the Baroness Wootton of Abinger.5

 In many areas in which formal scientific data are not available, we shall have to rely on expert opinion, and in such instances reference will be made to some of the observations presented in these aforementioned governmental reports. A general overview of the effects of cannabis will be followed by a more detailed examination of certain selected scientific studies. Primary concern will be given to recent publications.

 153. Physiological Effects. The short-term physiological effects of cannabis are usually slight and apparently have little clinical significance. The following effects have been established in adequately controlled studies: increase in heart rate, swelling of the minor conjunctival blood vessels in the membranes around the eye, and minor unspecific changes in the electroencephalogram (EEG). Also commonly noted, but less well documented, are: a slight drying of the eyes and nasal passages, initially stimulated salivation followed by dryness of the mouth, throat irritation and coughing during smoking, and increased urination. Less commonly, nausea, vomiting, diarrhoea or constipation are reported. These gastro-intestinal disturbances rarely occur with smoked cannabis, although nausea is not uncommon when large quantities are taken orally. Changes in blood sugar level and blood pressure have been inconsistently reported. Appetite is usually stimulated. Contrary to popular belief, there is little evidence of pupil dilation. In some individuals, incoordination, ataxia and tremors have been observed and chest pains, dizziness and fainting have occasionally been noted, usually at high doses. Physiological hangover effects have been described but are rare, even after considerable intoxication.

 154. Cannabis has little acute physiological toxicity - sleep is the usual somatic consequence of over-dose. No deaths due directly to smoking or eating of cannabis have been documented and no reliable information exists regarding the lethal dose in humans. One fatality, however, was reportedly caused by distention of the bowel during a prolonged bout of gross over-eating under the acute influence of cannabis.134

 155. There is little reliable information on the long-term effects of cannabis use. There are numerous reports from Eastern countries of chronic ill-health among very heavy long-term users of hashish. Most commonly reported are minor respiratory and gastro-intestinal ailments. These studies rarely provide a control group of comparable non-users for a reference standard, and clinical findings are usually confounded with a variety, of social, economic and cultural factors which are not easily untangled. Consequently, much important work remains to be done in this area. The British Cannabis report (1968) states: 5

 Having reviewed all the material available to us, we find ourselves in agreement with the conclusion reached by the Indian Hemp Drugs Commission appointed by the Government of India (1893-1894) and the New York Mayor's Committee on Marihuana (1944), that the long-term consumption of cannabis in moderate doses has no harmful effects.

 156. Some observers have suggested that chronic smoking of cannabis might produce carcinogenic effects similar to those now attributed to the smoking of tobacco, although no evidence exists to support this view at this time. A meaningful comparison is difficult to make since the quantity of leaf consumed by the average cigarette smoker in North America is many times the amount of cannabis smoked by even heavy users. The present pattern of use by regular cannabis smokers in North America is more analogous to intermittent alcohol use (e.g., once or twice a week), than to the picture of chronic daily use presented by ordinary tobacco dependence. However, the deep inhalation technique usually used with cannabis might add respiratory complications.

 157. Recently, there have been conflicting reports that large quantities of cannabis extract, injected into pregnant females of certain strains of rodents, may cause abnormalities in the offspring.85 These disparate results can not be simply extrapolated to humans and at this time there is no scientific evidence that cannabis adversely affects human chromosomes or causes deformed children.

 158. Psychological Effects. The psychological effects of cannabis vary greatly with a number of factors and are often difficult to predict. The dose, type of preparation, and rate and mode of administration can greatly influence the response, even if the effective doses and peak responses are made comparable. Furthermore, the psychological effects depend to a considerable degree on the personality of the user, his past experience with cannabis or other drugs, his attitudes, and the setting in which the drug is used.

 Although 'hash' may be many times more potent than marijuana, the effects of these two forms of cannabis, as usually used in North America, are often indistinguishable. It has been reported that most experienced individuals smoke to attain a certain effect or level of 'high', and adjust the dose according to the potency of the substance used. 'Grass' and 'hash' are generally used interchangeably and great variations in potency of different samples are accommodated by the experienced user through a 'titration' of dose - i.e., intake is stopped when the smoker reaches a personally comfortable level of intoxication. Such precision is generally not possible with oral use, however, due to the long delay in action, and a 'non-optimal' effect is therefore much more likely to occur with this practice. In some Eastern countries, different social norms have evolved around the different forms of cannabis, and the pattern of drug use associated with bhang drinks may be quite different from that seen in regular hashish users. Long-term heavy cannabis users invariably prefer the more potent ganja or hashish.45, 107

 It is often difficult to find descriptions of the psychological affects of marijuana that are free from value judgements. Many effects seem to take on good or bad connotations depending on the circumstances in which they occur, the personal attitudes of the individual undergoing the experience, and the orientation of the observer who is recording them. Moreover, since many of the significant psychological effects are intensely personal, the laboratory scientist often has little opportunity to make objective measurements, and must rely on subjective, introspective reports, communicated verbally through a language system which is frequently inadequate.

 159. Cannabis is one of the least potent of the psychedelic drugs, and some might object to its being classified with LSD and similar substances. It is often suggested that marijuana is a mild intoxicant, more like alcohol.132 There is evidence, however, that high doses of cannabis in some individuals may produce effects similar, in some respects, to an attenuated LSD experience. While such effects are rarely reported, many milder aspects of the psychedelic experience regularly occur with a cannabis 'high'. The outline of potential reactions to psychedelic drugs presented in the section on LSD include: psychotic and non-psychotic adverse reactions, psychodynamic, cognitive, aesthetic, and psychedelic-peak (transcendental) or religious experiences. While analogous experiences may occur in varying degrees with cannabis, the quality of the effects is reportedly different, the intensity considerably lower, and the overall response more controllable than with the more powerful psychedelic drugs. It would be incorrect to say that cannabis in moderate dose actually produces a mild LSD experience; the effects of these two drugs are physiologically, behaviourally and subjectively quite distinct. Furthermore, since no cross-tolerance occurs between LSD and THC the mechanism of action of these two drugs is thought to be different.109

 160. A cannabis 'high' typically involves several phases. The initial effects are often somewhat stimulating and, in some individuals, may elicit mild tension or anxiety which usually is replaced by a pleasant feeling of well-being. The later effects usually tend to make the user introspective and tranquil. Rapid mood changes often occur. A period of enormous hilarity may be followed by a contemplative silence.

 Psychological, effects which are typically reported by users include: happiness, increased conviviality, a feeling of enhanced interpersonal rapport and communication, heightened sensitivity to humour, free play of the imagination, unusual cognitive and ideational associations, a sense of extra-ordinary reality, a tendency to notice aspects of the environment of which one is normally unaware, enhanced visual imagery, an altered sense of time in which minutes may seem like hours, changes in visually perceived spatial relations, enrichment of sensory experiences (subjective aspects of sound and taste perception are often particularly enhanced), increased personal understanding and religious insight, mild excitement and energy, (or just the opposite), increased or decreased behavioural activity, increased or decreased verbal fluency and talkativeness, lessening of inhibitions, and at higher doses, a tendency to lose or digress from one's train of thought. Feelings of enhanced spontaneity and creativity are, often described, although an actual increase in creativity is difficult to establish scientifically. While most experts agree that cannabis has little specific aphrodisiac (sex stimulating) effect, many users report increased enjoyment of sex and other intimate human contact while under the influence of the drug.93,161

 Less pleasant, experiences may occur in different individuals, or possibly in the same individuals at different times. Some of these reactions may include: fear and anxiety, depression, irritability, nausea, headache, backache, dizziness, a dulling of attention, confusion, lethargy, and a sensation of heaviness, weakness and drowsiness. Disorientation, delusions, suspiciousness and paranoia, and in some cases, panic, loss of control, and acute psychotic states have been reported. Schwarz196 has compiled an extensive catalogue of reports of adverse symptoms which have been attributed to cannabis in the world literature.

 161. The possibility of psychiatric disorders associated with cannabis use has received considerable attention. Although there are some well documented examples of very intense and nightmarish short-term reactions (usually among inexperienced users in unpleasant situations and with high doses), these cases seem to be relatively rare and generally show a rapid recovery. Although many regular users have had an experience with cannabis which was in some way unpleasant, 'freak-outs' are apparently rare. Ungerleider230 has reported 1,887 'adverse reactions' to marijuana in the Los Angeles area. These data are difficult to interpret since no clear definition of adverse reaction is provided and no follow-ups were made. By contrast, Unwin in Montreal reports:233

"I have seen only three adverse reactions in the past two years; all following the smoking of large amounts of hashish and all occurring in individuals with a previous history of psychiatric treatment for psychiatric or borderline conditions."

 The few cases of prolonged psychosis which have been reported have usually been attributed to an earlier personality predisposition, although this hypothesis is not always easy to substantiate. Earlier notions of a specific 'cannabis psychosis' have generally been abandoned since there is little evidence of such a distinct psychiatric entity. Smith206 in San Francisco, reports that he has never observed 'cannabis psychosis' in over 35,000 marijuana users seen at the Haight-Ashbury clinic. But a recent psychiatric report described several psychotic reactions occurring in American soldiers in Vietnam, who had used cannabis.218 The psychiatrist believed that the psychotic episodes may have been related to cannabis use. This emphasizes the need for caution before any generalizations about the evidence of psychiatric complication with cannabis use are made - particularly in individuals who have consumed large doses of potent material under conditions of increased physical and psychological stress. Such general conditions are, of course, by no means restricted to military operations.

 162. There have been a few reports of 'flash-backs' or spontaneous recurrences of certain cannabis effects some time after the last use of the drug, although such events are apparently quite rare. In addition, cannabis has also been reported to have precipitated LSD recurrences in some heavy users of LSD.123

 Only a few adequate laboratory investigations have been made of the effects of cannabis on normal psychological functioning. Most of the data indicate little change under the conditions tested, although reports of both impaired and improved performance have been made. Because of the perceptual, cognitive and psycho-motor effects often attributed to cannabis, it seems reasonable to expect that in high doses the drug would impair automobile driving. Many regular users feel this is so and avoid driving, while others content that they are more careful and are probably better drivers when slightly 'high'.93 There is no available evidence that cannabis has been a significant factor in traffic accidents. The one study testing cannabis effects on driving skills found little impairment to be caused by a 'mild social high'.61 Some of the studies pertinent to these topics will be discussed in more detail at the end of this section.

 163. A study by Suchman217 suggests a close association between the use of marijuana in some young people and adherence to what is termed the 'hang-loose' ethic. Central to this notion is the questioning of such traditional patterns of behaviour and belief as, conventional religion, marriage, pre-marital chastity and the accumulation of wealth. Subscribers to this ethic apparently do not necessarily reject the mores of the established order, but are strongly critical of them. In this study, the stronger the student embraced the ethic the more favourable he was towards marijuana use. Smoking marijuana was highly associated with 'nonconformist' behaviour such as participating in mass protests and was more likely to be reported by those students who were dissatisfied with the education they were receiving. The 'hang-loose' ethic, while it may represent antagonism to the conventional world, does not appear to create apathy and withdrawal. The investigator suggests that the smoking of marijuana is part of the behaviour associated with this ethic rather than the cause of it.

 A somewhat different view is suggested by McGlothlin and West154 on the basis of clinical observation. They have described an 'amotivational syndrome' in some heavy marijuana users in North America. It is suggested that such use of marijuana may contribute to some characteristic personality changes including apathy, loss of effectiveness, diminished capacity or willingness to carry out complex long-term plans, endure frustration, follow routines or successfully master new material. The interpretation of these observations is complicated by the fact that such individuals are usually involved with other drugs as well as cannabis.

 Several Eastern studies have suggested that chronic high-dose use of the more potent preparations of cannabis may have detrimental effects on the individual. One of the most comprehensive reports was that of the Chopras in 1939.45 An eight-year study was carried out on a sample of 1,238 cannabis users. With regard to moderate doses, users of relatively mild bhang reported a general feeling of well-being, relief from worry and sharpened appetite. Heavy users were often found to suffer from several adverse symptoms. In some instances, cannabis use was seen as an attempt at self-medication in response to theme disorders rather than as the cause.

 The researchers report that among the ganja and charas users, a small percentage suffered from serious psychiatric disorder, and minor emotional problems, including impairment of judgement and memory, were observed in the majority of these subjects. According to the authors, a significant proportion of the group had pre-existing neurotic tendencies which may have contributed to their problem of drug use. Heavy users were often observed to show marked inactivity, apathy and self-neglect. The majority of those who took small doses of any of the cannabis preparations felt that the overall consequences of their drug habit were nil or beneficial, while the majority of those who chronically took heavy doses, thought the practice harmful. These subjective judgements were generally consistent with the clinical observations reported.

 165. This and other reports from Eastern countries are difficult to interpret and apply to the Western situation. To begin with, no equivalent data are presented from a comparable control group of non-users of similar social and economic background (although some comparisons among users are possible) and there is no means of estimating the representativeness of the sample studied. In addition, there are many social and economic factors which complicate cross-cultural comparisons. The use of cannabis has a different meaning in Eastern cultures where a long history and tradition surrounds its use - than it does in the West, where it is a relatively recent phenomenon. Often, concepts of normalcy and deviancy differ considerably from one culture to another. In addition, the Eastern cannabis user generally consumes larger quantities of more potent forms with greater frequency than does the Western user.

 166. Although the possession of cannabis is a crime, and in obtaining it an individual must normally come in contact with other individuals committing drug offences, there is no scientific evidence that cannabis itself is responsible for the commission of other forms of criminal behaviour. Chopra and Chopra45 suggest that cannabis use may, in fact, actually reduce the occurrence of crime and aggression by decreasing general activity. While criminals may be more likely to use cannabis than other individuals, few crimes committed under the influence of marijuana have been documented, and a casual relationship between the drug use and other illegal behaviour has not been established. It may well be that an individual who is inclined to commit one illegal act (e.g., a drug offence), may also be more likely than average to transgress in other areas as well. Some observers feel that the lessening of inhibitions often reported with cannabis use might, in certain delinquent individuals, increase the likelihood of asocial behaviour. In a 1967 judgement, rendered by Judge G. Joseph Tauro, Chief Justice of the Supreme Court of Massachusetts, in the Boston trial of two men (Leis and Weiss) accused of trafficking cannabis, the following statement appears:54

 The brief presented to the Commission by the Royal Canadian Mounted Police dealt at considerable length with the alleged association of illegal drug use and criminal behaviour in Canada. This evidence is discussed later in the report.

 The British Cannabis report (1968) states that:5

"In the United Kingdom the taking of cannabis has not so far been regarded, even by the severest critics, as a direct cause of serious crime.... The evidence of a link with violent crime is far stronger with alcohol than with the smoking of cannabis."

 167. Tolerance and Dependence. While gross tolerance to the major effects of cannabis does not seem to occur in humans, there are many more subtle aspects of this situation which have yet to be clarified. Although there is little tendency for intermittent users to increase dose, certain cannabis effects may be modified by repeated experiences with the drug. Many investigators have pointed out that in some individuals there appears to be a 'reverse' tolerance - i.e., smaller doses may produce the desired effects after the user has become familiar with the drug. Many individuals experienced little or no effect the first time they smoked cannabis. Whether this is due to initially poor smoking technique, some learning or psychological adaptation process, or perhaps some more molecular pharmacological sensitization, is uncertain. On the other hand, a few individuals appear to be extremely sensitive to the effects of cannabis at the beginning and may initially report intense, ornate, and perhaps frightening experiences which are rarely, if ever, equalled in subsequent administrations.

 168. Investigators have reported that regular users learn to direct or control some of the psychological and behavioural effects while subjectively 'high' and may be able to perform certain functions better than non-users given the same dose. This would suggest that some sort of differential selective adaptation or tolerance may develop to some of the initially 'uncontrollable' effects.User4 remain sensitive to the rewarding effects of the drug since there is generally no marked inclination for them to increase dosage. Some users report that if they stay 'high' for several days in a row the drug experience loses much of its freshness and clarity and, consequently, they prefer intermittent use.

 There are reports of chronic, heavy users from the East who consume what would seem to be rather large quantities by Western standards.24,30 Whether this reflects some degree of tolerance with heavy use in these users or differences in desired effects or general drug-using norms, is not known.

 169. Physical dependence to cannabis has not been demonstrated and it would appear that there are normally no adverse physiological effects or withdrawal symptoms occurring with abstinence from the drug, even in regular users. On the other hand, there have been several reports from the Far East and Middle East, of irritability, mild discomfort, and certain behavioural symptoms occurring after withdrawal of the drug in chronic heavy users.24 It must be kept in mind that these cases are not clearly documented and that the purity of the substances involved is not certain. Since hashish is smoked with large quantities of tobacco and other drugs in many Eastern countries, these mixtures could be responsible for the minor withdrawal symptoms reported.

 170. No controlled research has been done into the effects of discontinued cannabis administration after unusually high doses of the unadulterated substance have been given over a prolonged length of time. While such an extreme situation may appear to be of little social significance, it should be noted that physical dependence on the sedatives (alcohol, barbiturates and tranquillizers) usually occurs in only a small minority of users who take abnormally large quantities of the drug for extended periods of time.

 171. The presence or absence of psychological dependence in a given situation, of course, depends on one's definition of the term. While many cannabis users in North America seem to take the drug once or twice a week, in a social context similar to that in which alcohol is normally consumed, and readily abstain for weeks or months with no ill effects, there is a small minority of users who smoke it daily and whose regular routine and sense of well-being is disrupted if they are unable to obtain the drug. Most users apparently find the drug pleasant and desirable, and often will go out of their way to acquire it - even at the risk of criminal penalty. However, the craving and urgency associated with opiate narcotic of sedative (or tobacco) dependence do not seem to occur. There are reports from the East that considerable psychological dependence has occurred in a minority of individuals in whom the use of the drug has become a major component of their existence.107

 172. The minority of cannabis users studied in North America have had experience with a variety of other psychoactive drugs, alcohol and tobacco being the most frequently mentioned. As might be expected, most of those who smoke cannabis first acquired a regular tobacco habit.

 A link between tobacco smoking and marijuana use has been suggested by Rowell, who worked closely with the United States Bureau of Narcotics in the 1930s:191

"Slowly, insidiously, for over three hundred years, Lady Nicotine was setting the stage for a grand climax. The long years of tobacco using were but an introduction and training for marijuana use. Tobacco, which was first smoked in a pipe, then as a cigar, and at last as a cigarette, demanded more and more of itself until its supposed pleasures palled, and some of the tobacco victims looked about for something stronger. Tobacco was no longer potent enough."

 173. The relationship between cannabis and alcohol use has been the subject of much controversy. Many marijuana users claim that they have drastically reduced their consumption of alcohol, or quit it, since using cannabis. They often suggest that cannabis may be a cure for society's alcohol ills. The considerable hostility towards and rejection of alcohol expressed by many cannabis-using youth, however, is clearly not reflected in the majority of cannabis users. In general, survey studies find that those who use alcohol are more likely than 'teetotallers' to use cannabis, and most cannabis users still use alcohol. We have no information as to what effects, cannabis has on an individual's drinking behaviour and overall alcohol intake. It is not clear whether cannabis tends to replace alcohol as an intoxicant in the user population or whether the use of these drugs is addictive without significant interaction, or if the use of one of these drugs potentiates the use of the other. It appears that, if used simultaneously, the alcohol effects dominate and many of the psychedelic aspects of cannabis are suppressed. For this reason, many cannabis users refuse to mix the drugs even if they may enjoy one separately.

 The question of comparing benefits and ills of alcohol and cannabis has become a popular and engaging endeavour. Due to the profoundly different social connotations and patterns of use, as well as scientific knowledge of these drugs, such a comparison must be made on limited and tenuous grounds.

 174. In the United States, the majority of persons studied who had been dependent on opiate narcotics, had previous experience with cannabis (and were usually heavy users of alcohol). In Canada this has less often been the pattern, and it appears that heavy use of sedatives (alcohol and barbiturates) rather than cannabis has most frequently preceded heroin use.246,215

 It has been suggested that the Canadian pattern is becoming more similar to the United States experience.

"The charge that marijuana 'leads to the use of addicting drugs' need to be critically examined. There is evidence that a majority of the heroin users who come to the attention of public authorities have, in fact, had some prior experience with marijuana. But this does not mean that one leads to the other in the sense that marijuana has an intrinsic quality that creates a heroin liability. There are too many marijuana users who do not graduate to heroin, and too many heroin addicts with no known prior marijuana use, to support such a theory. Moreover there is no scientific basis for such a theory."

 The most reasonable hypothesis here is that some people who are predisposed to marijuana are also predisposed to heroin use it may also be the case, that through the use of marijuana a person forms the personal associations that later expose him to heroin.

With a similar orientation, the British Cannabis report (1968) states:5

 ". . . we have concluded that a risk of progression to heroin from cannabis is not a reason for retaining the control over this drug (cannabis)."

 175. Many heavy users of cannabis reportedly also experiment with a variety of other drugs, including amphetamines as well as psychedelic substances. Again, marijuana is often the first drug (other than alcohol and tobacco) taken by youthful multi-drug users. The role of cannabis in the 'progression' to other drugs has not been adequately studied and it is unclear whether it plays a predisposing role, or is often used earlier simply because of its wider availability and social acceptance.

 176. While no cross-tolerance occurs between cannabis and the other psychedelic drugs or the stimulants, considerable mention has been made of 'multi-drug' psychological dependence in which individuals may seem to depend on a variety of drugs in general, rather than on any particular chemical substance.

 177. Initiation of Cannabis Use. Cannabis users are usually 'turned on' for the first time by friends and associates who have had previous experience with the drug. There is little evidence of aggressive 'pushers' being responsible for the initiation of cannabis smoking, although many individuals have reported considerable peer-group pressure to try it. The distribution or trafficking of cannabis is largely carried out in the same social manners and is usually handed from friend to friend, although there are some individuals whose motivation for trafficking is primarily commercial. Some of the marijuana in Canada is 'home-grown' but most apparently comes from Mexico and the southern United States.

 178. I. In 1939, after consulting with the New York Academy of Medicine, Mayor La Guardia of New York appointed a special scientific committee to investigate the effects of marijuana, both in the community and under laboratory conditions. The final report entitled The Marijuana Problem in the City New York: Sociological, Medical, Psychological and Pharmacological Studies149 was published in 1944, and is still one of the most widely quoted and comprehensive studies of cannabis.

 The report provoked considerable controversy, and although it has been generally well received by the scientific community, certain other individual were quite vociferous in expressing their dismay at the committee's conclusions. O.J. Kalant120 of the Addiction Research Foundation, has prepared a careful critical analysis of the Mayor's report. She observed that: 'Judged from a purely scientific standpoint this study deserves neither the extravagant praise nor the vicious attacks to which it has been submitted.'

 179. The field work for the sociological study was undertaken by six specially trained police officers. The squad 'lived' in the environment in which marijuana smoking or peddling was suspected. They frequented poolrooms, bars and grills, dance halls, subways, public toilets, parks and docks. On the basis of their observations, the following conclusions were drawn: The distribution and use was centred in Harlem. While the cost of marijuana was low and therefore within range of most persons, the sale and distribution was not under the control of any single organized group. The consensus among users was that the drug created a definite feeling of adequacy. The practice of smoking marijuana did not lead to addiction in the medical sense of the word, did not lead to morphine or heroin or cocaine addiction, and no effort was made to create a market for opiate narcotics by stimulating the practice of marijuana smoking. Marijuana was not the determining factor in the commission of major crimes, nor was it the cause of juvenile delinquency. Finally, 'the publicity concerning the catastrophic effects of marijuana smoking in New York City is unfounded.'

 180. The clinical studies were conducted with an experimental group of 77 persons - 72 of whom were inmates of various New York Prisons. Forty-eight of these subjects had used marijuana previously and some had been heavy users of opiate narcotics. Both orally ingested cannabis concentrate and ordinary marijuana cigarettes were administered in various quantities.

 A feeling of euphoria, occasionally interrupted by unpleasant sensations, was the usual response to cannabis. Also noted were other common aspects of a marijuana 'high', such as laughter and relaxation. No signs of aggression occurred, although some indications of anti-social feelings were expressed. Dizziness, a light floating sensation, dryness of the throat, thirst, an increase in appetite (particularly for sweets), unsteadiness and a feeling of heaviness of the extremities, were among the common somatic symptoms noted. Nausea and vomiting occasionally occurred with oral ingestion. Most effects seemed to increase with dose and were often more pronounced on those who had not previously used cannabis.

 181. There were 9 cases of psychotic reaction in the prisoners studied. In 6 instances, acute or short-term adverse reactions characterized by '... mental confusion and excitement of delirious nature with periods of laughter and anxiety' occurred. Three cases of 'true' psychosis appeared to be associated with the experiment. 'The precise role marijuana in the psychotic states of the three unstable persons is not clear.' In the first subject 'the psychotic episode was probably related to epilepsy.' In the case of the second and third subjects, the fact that they were sent back to prison to complete their sentences must be considered an important, if not the main factor in bringing on the psychosis.' None of the nine individuals had been a regular user of cannabis. The researchers pointed out, however, that marijuana can bring on a true psychotic state under certain circumstances in predisposed individuals.

 182. The most consistent physiological effects reported were: a temporary increase in heart rate, an inconsistent increase in blood pressure, and increase in frequency of urination, dilated pupils, and a moderate increase in blood sugar level and basal metabolism. Other organic and systematic functions were unchanged. It should be pointed out that the tests reported were not conducted under controlled double-blind conditions, and some of these findings have not been confirmed in later controlled studies.

 183. Simple psychomotor functions were only affected slightly by large doses, and negligibly or not at all by small doses of marijuana. More complex functions, hand steadiness, static equilibrium, and complex reaction time were impaired by both dose levels. Generally, non-users were more affected by the marijuana than those with previous marijuana experience. Strength of grip, speed of tapping, auditory acuity, 'musical ability' and estimation of short time intervals and linear distances were unchanged. Placebos were not generally used in this section and the details of the statistical analysis were not presented.

 184. In the section on Intellectual Functioning, a variety of psychological tests designed to measure aspects of intelligence, learning, memory and performance were administered. Two doses of oral concentrate were used in most instances. The author concludes that marijuana ingestion ... has a transitory ,adverse effect on mental functioning', with the greatest impairment at high dose on tasks involving complex functions. No statistical analysis was done to distinguish drug effects from statistical analysis was done to distinguish drug effects from random variation, however, and again, no controlled double-blind design was used. Furthermore, the author's conclusions are not always consistent with the evidence which, for example, suggests some improvement in verbal abilities and certain other functions after marijuana ingestion. These data are not discussed. The author notes that 'indulgence in marijuana does not appear to result in mental deterioration'.

Kalant has noted with respect to this section: 120

"In summary, the results seem to bear out the conclusion that big enough doses of marijuana impair variety of mental functions, while small doses may improve some of them. These conclusions are only tentative, because the author presents no statistical treatment of the data."

 185. The 'Emotional and General Personality Structure' of varying numbers of users and non-users were studied before and after several doses of cannabis. The effects of low dose were generally pleasant and favourably received by the subjects, while the high dose seemed more likely to produce anxiety, distress, and a sense of insecurity. The committee concluded:

 Under the influence of marijuana the basic personality structure of the individual does not change, but some of the more superficial aspects of his behaviour show alteration. The new feeling of self confidence induced by the drug expresses itself primarily through oral rather than through physical activity. There is some indication of a diminution in physical activity. The disinhibition which results from the use of marijuana releases what is latent in the individual's thoughts and emotions, but does not evoke responses which would be totally alien to him in his undrugged state.

 186. A comparison between users and non-users as regards the possibility of physical and mental deterioration as a consequence of marijuana use was made on 48 users, some of whom had been smoking regularly for two to seventeen years. The investigators concluded that:

"There is definite evidence in this study that the marijuana users were not inferior in intelligence to the general population and that they had suffered no mental or physical deterioration as a result of their use of the drug."

 187. The therapeutic use of cannabis in the treatment of opiate narcotic addicts was explored in 56 patients. Tentative conclusions suggest improved appetite and mood, less severe symptoms and a generally improved clinical picture during withdrawal. Again no control group was studied.

The Committee reported:

"From the study as a whole, it is concluded that marijuana is not a drug of addiction, comparable to morphine, and that if tolerance is acquired, this is of a very limited degree.... The habit depends on the pleasurable effects that the drug produces."

 These views were based largely on interviews with hundreds of users, the sociological studies and the laboratory investigations. Some observers have pointed out that these conclusions may not apply to the conditions of heavy chronic use sometimes reported in Eastern countries.

 188. Some individuals have criticized the research for often using high doses of little social relevance - the authors admit that users, if left to their own devices, tend to approximate the lower doses used in the experiment. Other investigators feel that more chronic users of higher doses should have been studied for the investigation of long-term effects including tolerance and dependence.

 189. In summary, although the La Guardia report remains one of the more significant contributions to the cannabis literature, the conclusions must be qualified in accordance with the numerous weaknesses in the experimental methodology: blind and placebo controls were absent and statistical analyses often lacking, reporting was occasionally biased when the data were ambiguous, sample selection may not have been adequate for certain conclusions in the sociological study, and the almost complete use of prison inmates as subjects in the clinical studies and hospital ward setting may further restrict generalizations.

 190. II. Isbell et al109 investigated the effects of various doses of smoked and orally ingested tetrahydrocannabinol (THC)in a group of former opiate narcotic addicts who had also had experience with marijuana. The drug was compared to an inactive placebo control in a single-blind design (i.e., the researchers, but not the subjects, knew which samples were being tested).

 191. Regardless of dose and route of administration, THC caused no significant change in pupillary size, respiration rate, blood pressure, or knee-jerk reflex threshold. Heart pulse rate was consistently elevated, and swelling of the conjunctival blood vessels in the membrane around the eyes occurred after the higher doses. In both physiological and psychological measures, THC (at a standard dose) was found to be two to three times as potent when smoked as when taken orally.

 192. Patients identified the drug as being similar to marijuana and some suggested that it was something like LSD or cocaine as well. Euphoria was consistently noted and no mention was made in the report of unpleasant adverse reactions. Psychological changes included '. . - alterations in sense of time and in visual and auditory perception (usually described as keener).' With higher doses, both smoked and orally ingested, '. . .marked distortion in visual and auditory perception, depersonalization, derealization and hallucinations, both auditory and optical, occurred in most patients. THC, therefore is a psychotomimetic drug and its psychotomimetic effects are dependent on dose.' Such occurrences may also appear in some individuals as 'idiosyncratic' reactions at lower doses. It had been noted that the symptoms which Isbell has labelled 'psychotomimetic' might be called 'psychedelic' by scientists with a different orientation.

 193. The application of these findings to marijuana use as it occurs in North America is unclear. Some observers, in both lay and scientific circles, have interpreted this report as an indication of the dangers of marijuana, while other scientists question the relevance of these findings in relation to the 'real world' of marijuana usage.251

 194. III. In 1968, Weil, Zinberg and Nelsen 239,240 reported the first adequately controlled experiment on cannabis effects in humans. The primary section of the study is concerned with effects on nine subjects who were inexperienced with cannabis. The researchers gave two different doses of marijuana (0.5 and 1.0gm of 0.9% THC) and an inactive placebo substance in a controlled 'double-blind' situation - i.e., neither the subjects nor the researchers knew at the time of the experiment which dose of cannabis or placebo was administered. This procedure greatly reduces the influence of expectations and bias on the part of both subjects and researchers. In addition to the naive subjects, eight chronic marijuana users (who normally smoked daily or every other day) were tested with the high dose only. No placebo was used with these subjects since the authors felt that experienced marijuana smokers could readily distinguish the placebo from the 'real thing', and consequently a true placebo control was not possible. Subjects took either the drug or placebo by a standard and uniform inhalation method designed to minimize practice effects and individual differences in smoking technique. Subsequently, they were tested on a battery of standard psychological and psychomotor tasks, and certain physiological measurements were taken in a neutral laboratory setting.

 195. The physiological findings were quite straightforward: heart rate was increased moderately, no significant change in respiration rate occurred, blood sugar level was unchanged (although the timing of the samples may not have been optimal), no change in pupil size was seen and a slight swelling of the conjunctival blood vessels (producing a reddening of the membranes around the eye) occurred. The researchers suggest that the near absence of significant physiological effects '... makes it unlikely that marijuana has any seriously detrimental physical effects in either a short-term or long-term usage.'

 196. The capacity for sustained attention (Continuous Performance Test) was unaffected by cannabis in both the naïve and chronic user groups, even when a flickering strobe light was presented to provide distraction. Muscular coordination and attention performance (Pursuit Rotor Test) declined as dose was increased in naïve subjects, but improved slightly after marijuana use in the chronic users. (This improvement was considered a result of practice rather than a drug effect but can not be properly evaluated due to the lack of a placebo measurement in the experienced users.) Performance on the Digit Symbol Substitution Test, (a simple test of cognitive function often used in I.Q. tests) was impaired in the naïve groups, while the experienced smokers started off at a reasonable base line and actually improved slightly when they were 'high' - a trend which can not be accounted for solely by practice. A tendency to overestimate time was also noted in these subjects. The researchers caution that the differences between users and nonusers in this study must only be considered a trend since the testing situations were not strictly comparable for the two groups.

 197. Subjects were given five minutes to talk on 'an interesting or dramatic experience' and the content of the verbal report was analysed. Marijuana did not impair the understandability of the material as measured by the Cloze method, although judges could consistently distinguish the transcripts of pre- and post-drug samples in both the naive and experienced groups. A 'strange' quality in the post-drug samples was noted but not easily quantified. The investigators suggested that marijuana may temporarily interfere with short-term memory - i.e., the ability to retrieve or remember events occurring in the past few seconds. They feel that this may explain why many marijuana smokers, when very 'high', may have trouble remembering, from moment to moment, the logical thread of what is being said. Controlled investigation of this hypothesis is currently under way.

 198. The experienced subjects were asked to rate themselves on a scale from one to ten, with ten representing the 'highest' they had ever been. Ratings given were between seven and ten, with most subjects at eight or nine. This would suggest that the sample was of reasonable potency and the smoking technique effective. On the other hand, with the same dose and smoking technique, only one of the naive subjects had, a definite marijuana 'high'. (Interestingly, he was the one subject who had earlier expressed an eagerness to 'turn on'.) The researchers point out that the introspective report of an individual is the only way to determine if he is 'high' on marijuana or not. There are, as of yet, no known objective signs which allow one to identify this state.

 199. There was no change in mood in the neutral laboratory setting in either naive or chronic user subjects, as measured by self-rating scales and a content analysis of the verbal sample. There were no adverse marijuana reactions of any kind in any of the subjects, although tobacco cigarettes smoked during a practice session, using the standard technique produced acute nicotine reactions in five subjects which 'were far more spectacular than any effects produced by marijuana'. The authors conclude:

"In a neutral setting persons who are naive to marijuana do not have strong subjective experiences after smoking low or high doses of the drug, and the effects they do report are not the same as those described by regular users of marijuana who take the drug in the same neutral setting. Marijuana naive persons do demonstrate impaired performance on simple intellectual and psychomotor tests after smoking marijuana; the impairment is dose-related in some cases. Regular users of marijuana do get high after smoking marijuana in a neutral setting but do not show the same degree of impairment of performance on the test as do naive subjects. In some cases, their performance even appears to improve slightly after smoking marijuana."

 200. The New Republic, in an editorial responding to this report, wrote: 'While pot heads may legitimately ask, "So what else is new?" the study may have a pacifying influence on parents and officials who fear the drug on the basis of unsubstantiated horror stories.'251 While numerous scientists have expressed similar views, the study does provide a long overdue empirically adequate beginning to the scientific study of marijuana effects on humans. While this study has implications extending beyond the laboratory, there has been a tendency in the popular press to overgeneralize from the results. It would be imprudent to extrapolate the findings into social and legal areas for which the study was not designed and is not appropriate.

 201. IV. Jones and Stone116 in 1969 reported that smoked marijuana (equivalent to Weil's low dose) compared to a placebo in ten 'heavy users' resulted in: moderately increased heart rate, altered electroencephalogram (EEG), over-estimation of time (but no change in time interval production), no effect on the ability to attend to relevant internal cues to the exclusion of irrelevant external cues (Rod and Frame test), and no effect on the Digit Symbol Substitution Test (the same measure of cognitive functioning employed in the Weil study). A double dose of marijuana (comparable to Weil's high dose) produced a deficit in visual information processing - the only test studied with this quantity of drug.

 202. The subjects were asked to rate the low dose and placebo on a scale from 0-100 as to marijuana quality. The mean rating were 66 for the low dose and 57 for the placebo, which was not a significant difference. While this suggests that the dose of marijuana used was probably too low to be very effective and may reduce the significance of the report, it is interesting that the supposedly inactive 'placebo' (with only a "trace" of THC) was given a rating suggesting moderate potency by ten heavy marijuana users in San Francisco. However, it appears that the subjective effects of the placebo and low dose marijuana, as measured by a self-rating subjective symptom check-list, may have been different, although no statistics are presented, and the figure containing this information does not clearly identify the placebo. At any rate, these findings suggest that at low doses a simple 'highness' dimension may not be easy to quantify reliably. Unfortunately, Weil did not get ratings on his low dose or placebo, and Jones did not assess the high dose, so a reconciliation is not possible with the present data.

 203. The researchers also studied a larger dose of marijuana extract (equivalent to 20 cigarettes) given orally, compared with a placebo and one dose of alcohol (producing blood alcohol levels of 0.06 to 0.12%). Several tasks were used with the same subjects. Certain comparisons among the conditions and drugs are possible, although the use of a single dose and slight variations in procedure limits the applicability of the findings.

 204. The marijuana smoked in low doses produced an 'unimpressive' high with a maximum effect at about 15 minutes and lasting about three hours, while the oral administration had a latency of almost two hours, a peak at three to four hours and mild subjective effects lasting eight to ten hours. The oral dose of marijuana occasionally produced nausea and in one case vomiting, and differed from the smoked material on several subjective dimensions. The results of the comparisons between the oral marijuana and the placebo were essentially the same as those discussed earlier for the smoked material. As a point of reference, the single alcohol dose did not affect performance on the Rod and Frame Test, produced an underestimation of time intervals, decreased rate of information processing, did not affect heart rate, and produced a slowing of the EEG. Little meaningful comparison can be made between alcohol and the other treatments at a single dosage level, however.

 205. The report is ambiguous and many important details of methodology and results are excluded in what appears to be a preliminary investigation. It should be noted that this study has only single-blind controls and the investigators knew which drugs were administered at the time of the experiment.

 206. V. A third recent experimental study of marijuana effects on humans was published by Clark and Nakashima46 in 1968 and is mentioned here since it is now frequently quoted and, also, to demonstrate some of the problems of interpreting inadequately controlled experiments. Several different doses of marijuana extract (of unknown THC content) were given to 12 marijuana naive subjects, and the effects recorded on eight psychological tests in 'one control and two or three subsequent sessions'.

 207. The study is unintepretable for a variety of reasons, some of which follow: since the control session and the various drug doses were given only once, and on separate days, drug and dose effects are indistinguishably confounded with various factors of treatment order (including practice and other learning effects), and natural variations in performance occurring from one day to the next; the researchers describe no basis, statistical or otherwise, for distinguishing the 'effects' from random variation; they report only trends in the data in one or two subjects selected on an unspecified basis, and give no indication of overall group effects; the numerical basis for the figures presented is unspecified; apparently no placebos were given on the 'control' day which was invariably the first session, yet the drug is frequently compared with the 'control' in individual subjects; apparently no 'blind' controls were provided in either the experiment or later data analysis; and the report is presented with a strong negative bias in the introduction and remainder of the article, which is not supported empirically. The authors infer marijuana-induced impairment only on the reaction time and 'digit code memory' tasks, although they provide no reliable evidence for the presence or absence of positive or negative marijuana effects on these or the other tests studied.

 Clark concludes that great individual variation exists among individuals in response to the drug. While this would seem a reasonable observation, effects have not been identified, much less the variance of their distribution assessed. The great variability in the data cannot be attributed solely to the drug for reasons outlined above. In summary, this study, conducted, financially supported and published by highly accredited individuals and institutions, adds nothing but confusion to the existing knowledge and should encourage scepticism regarding even modern 'scientific' information on marijuana.

 208. VI. Last year Crancer and associates,61 from the Washington State Department of Motor Vehicles, published the first experimental study of marijuana effects on automobile driving skills. A laboratory driving simulator was employed which had been shown previously to validly predict road accidents and traffic violations on the basis of speedometer, steering, braking, accelerator and signal errors measured during a programmed series of 'emergency' situations. This study has provoked considerable controversy, some of which may be dissipated if the different sections of the study are examined separately.

 209. Using a sophisticated methodological and statistical design, the effects of the single dose of marijuana (2 cigarettes) were assessed in 36 experienced marijuana smokers who used cannabis at least twice a month. In terms of total THC administered, the dose was about 22% greater than Weil's high dose and almost 2 ½ times the standard dose used by Jones. Crancer reports the effects as a 'normal social marijuana high', although this is not quantified in any way and it is not certain how this relates to the overall pattern of marijuana use in the population. Simulator scores were obtained at three intervals over a 4 ½ hour period. Control (no treatment) sessions were run, although no placebo substance was used since the investigators felt that a placebo would not be effective with experienced marijuana users.

 210. Overall performance under the single dose of marijuana was not different from the control. The main study was followed by two 'cursory' investigations. Four subjects were retested with three times the original drug dose and none showed a significant change in performance. Furthermore, four marijuana naive subjects were tested after smoking enough marijuana to become 'high' (all consumed at least the amount used in the main experiment and demonstrated an increase in heart rate in addition to subjective effects). No significant change in scores occurred with the drug in these subjects either.

The investigators caution that the study does not necessarily indicate that marijuana will not impair driving.

However, we feel that, because the simulator task is a less complex but related task, deterioration in simulator performance implies deterioration in actual driving performance. We are less willing to assume that non-deterioration in simulator performance implies non-deterioration in actual driving.

 211. One weakness of this part of the study is that apparently no standard and uniform smoking technique was employed and it is not certain how much of the active principle was actually absorbed. Although a biochemical method for detecting THC in the body has recently been developed, quantitative measurements have not been employed in any experimental marijuana studies. Although higher doses were tested in some subjects, this was not done with the same thoroughness as the main experiment and little can be asserted regarding a dose-response effect of marijuana on driving. It seems likely that if the dose were pushed high enough some impairment would occur, although this has not been empirically demonstrated.

 212. In order to obtain some standard reference point for this study, the subjects were also tested under a single dose of alcohol, designed to produce a blood alcohol level corresponding to the legal standard of presumed driving impairment in Washington (i.e., 0.10% blood alcohol level). The average number of errors under alcohol (97.4) was significantly greater than that acquired under either the normal or marijuana condition (each averaging 84.5 errors). While it is clear that a meaningful comparison of the two drugs cannot be based on a single dose of each, the alcohol data were obtained merely to provide a 'recognized standard' of impairment.

 Kalant118 has pointed out that the blood alcohol level of these subjects may have been considerably higher than the desired 0.10%, and that comparisons between the drugs must be made with caution due to the single doses used. He also suggests that although it would not have been easy for the subjects to 'fake' good driving performance under marijuana, an anti-alcohol bias, as often seen in marijuana users, could have resulted in poorer performance in the alcohol condition.

 If the limitations of the alcohol-marijuana comparison and the weakness of the marijuana dose-effect generalizations are realized, the over-all study provides interesting tentative information on the effects of a moderate quantity of marijuana on driving skills.

 213. VII. In general, studies of the long-term history of marijuana users have been based either on medical or criminal samples or on subjects selected because of current use. Each of these sources of subjects has considerable intrinsic sampling bias - which greatly complicates the interpretation of results. Recently, however, Robins and associates,187 reported the first study of the long-term outcome of marijuana use in a group not selected for deviant behaviour. The subjects were 235 Negro men who had gone to public elementary school in the black district of St. Louis, Missouri, in the early 1940s. While the characteristics of such a population may have questionable applicability to present marijuana use in Canada, this generally thorough study should be carefully considered. The data are largely based on recent retrospective personal interviews and official records. Subjects were classified according to adolescent drug use.

 214. Persons in this sample who had used marijuana (and no other drug except alcohol) differed significantly from non-marijuana users, in that the users had more often: drunk heavily enough to create social or medical problems, failed to graduate from high school, reported their own infidelity or fathering of illegitimate children, received financial aid, had adult police records for non-drug offences, and reported violent behaviour. While these findings indicate an association between marijuana use and these other behavioural characteristics in this population, causal variables have not been identified.

 215. The heavy use of alcohol in these subjects complicates the interpretation considerably. Every marijuana user also used alcohol, and drinking usually preceded marijuana use. Among the subjects who used only marijuana and alcohol, 47% had medical or social problems attributable to drinking ('the "shakes", liver trouble, family complaints, arrests, etc.') after the age of 25, and 38% of the users met the criteria for alcoholism. When those subjects who were classified as alcoholics were eliminated from the data (and the remainder of the problem drinkers left in) the only statistically significant difference between the marijuana users and the non-users was with respect to financial aid received in the past five years. Non-significant trends remained, however, which were generally similar to the earlier differences. Subjects who used 'harder' drugs (e.g., heroin, amphetamines and barbiturates) in addition to marijuana were significantly more deviant than the non-users, even after the alcoholics had been eliminated from the sample. Almost one-half of the subjects who had used marijuana also had used other drugs illegally.

 The alcoholics, in addition to having a history of early drinking, were also more likely to have used marijuana as adolescents. Unfortunately, no record of intensity of early drinking or marijuana use was obtained. A possible causal relationship between marijuana use and problem drinking, or vice-versa, or a possible third set of factors predisposing certain individuals to both alcoholism and marijuana use cannot be established or denied on the basis of the present data. The relationship between marijuana use and the use of harder drugs is also troublesome.

The authors conclude:

"One small study of the effects of drug use in 76 Negro adolescents can hardly serve to determine the laws of the land. But it may at least make us cautious in too readily supporting the view that marijuana is harmless, until some better evidence is available."

 216. VIII. The Addiction Research Foundation of Ontario has recently conducted a study of 232 confirmed marijuana users in Toronto.173 Prisons and court referrals provided about half of the subjects and the remainder were volunteers not contacted through criminal-legal channels. The majority came from middle-class or upper middle-class homes and 16% were students. The average age was 22 (range: 15-42) and males outnumbered females 4 to 1. The average duration of marijuana use was 2.7 years (range: 1-20).

 217. Preliminary observations suggest the following characteristics in this sample: the subjects tended to be multiple drug users (tobacco and alcohol were used by almost all of the subjects, more than half had tried LSD and speed, and one-third had tried opiate narcotics); most had 'trafficked' in marijuana, but usually just to friends; cannabis was generally used about twice a week in the company of friends, accompanied by passive rather than active behaviour; purported reasons for use were increased perception and awareness, other psychedelic effects, improved mood, and conviviality. Almost all subjects found the usual effects favourable although about a third had had at least one unpleasant experience (physiological or psychological) with the drug; about half had driven a car while under the influence of cannabis, and of these subjects, more than half felt that their driving ability was unimpaired by the drug; about half felt that cannabis had improved their lives, while some thought it had worsened things; the subjects 'tended to be underactive physically, engaging in passive pursuits'; about one-third subscribed to the belief in the 'protestant work ethic', while almost as many rejected it; almost one-third had committed non-drug criminal offences; one-half showed a swelling of the fine conjunctival blood vessels around the eye; nonspecific deviant EEGs were frequently seen; more than half were thought by a psychiatrist to be psychologically unstable or disturbed; and the group as a whole tended to be more imaginative and creative than what would be expected in the general population.

 218. The researchers stress that their findings demonstrate an association, and not necessarily a causal relationship, between the regular use of cannabis and other characteristics in this sample. While some of these results may be attributable to the selection or bias of the sample (e.g., half were contacted through criminal correction channels), much of the information may have general application. On-going analysis of the data should further clarify the results, although the lack of a comparable matched control group will undoubtedly preclude certain generalizations since we have little information regarding the incidence of many of the aforementioned characteristics in non-marijuana using individuals of similar social, economic and educational backgrounds. Furthermore, the frequent use of other drugs by these subjects may limit conclusions specific to cannabis use.

 219. IX. In response to questions raised in the British House of Commons, the Government of India, in 1893, appointed a commission to investigate and report on the cannabis ('hemp drugs') situation in India. The commission was instructed to inquire into the extent to which the hemp plant was cultivated, the preparation of drugs from it, the trade in those drugs, the extent of their use, and the effects of their consumption upon the social, physical, mental, and moral conditions of the people. The different forms of the drug, especially bhang, ganja, and charas (hashish), were to be studied separately. The Commission '…should ascertain whether, and in what form, the consumption of the drugs is either harmless or even beneficial as has occasionally been maintained'. In addition, they were asked to investigate certain economic aspects of the use of hemp (e.g., tax arrangements and import and export patterns), and also the potential political, social or religious results of prohibition. The Report of the Indian Hemp Drugs Commission (1894),107 including appendices, comprised seven volumes and totalled 3,281 pages.

 220. In 1968, Mikuriya,158 in the first thorough discussion of this report to appear in the Western scientific literature, suggested that this investigation

". . . is by far the most complete, and systematic study of marijuana undertaken to date.... It is both surprising and gratifying to note the timeless and lucid quality of the writings of these British colonial bureaucrats. It would be fortunate if studies undertaken by contemporary commissions, task force committees, and study groups could measure up to the standard of thoroughness and general objectivity embodied in this report ... many of the issues concerning marijuana being argued in the United States today were dealt with in the Indian Hemp Drugs Commission Report."

 Until recently only about a half dozen copies of this report were available in North America. In the introduction to a new printing of the primary volume in 1969, Kaplan121 observed:

 That this report, which remains today by far the most complete collection of information on marijuana in existence, should have been so completely forgotten in an era when controversy over the effects of the drug and, the wisdom of its criminalization has increased to such fervor is almost inexplicable.

 221. The Indian Hemp Drugs Commission received testimony from 1,193 witnesses of a total of 80 meeting in 30 cities. Over 300 medical practitioners were consulted and inquiries were made of Commanding Officers of all regiments of the Army, The commissioners investigated the records of every mental hospital in British India and evaluated separately each of the 222 cases admitted during the year 1892, in which some connection between hemp drugs and insanity had been suggested (these made up about 10 per cent of all admissions) Furthermore, all 81 cases of crimes of violence in India purported to have been caused by cannabis over the previous 20 years were investigated and re-examined. In addition, three laboratory experiments were conducted with monkeys to study the effects of cannabis on the nervous system.

 222. In the short time during which the full report has been available to us, we have not been able to prepare, at this interim stage, a thorough critical analysis of the document. However, the following quotations, taken from the summary of conclusions regarding the effects of hemp drugs, provide an overview of the findings:

 It has been clearly established that the occasional use of hemp in moderate doses may be beneficial. In regard to the physical effects, the Commission have come to the conclusion that the moderate use of hemp drugs, is practically attended by no evil results at all. There may be exceptional cases in which, owing to idiosyncrasies of constitution, the drugs in even moderate use of hemp drugs in even moderate use may be injurious, excessive use does cause injury. As in the case of other intoxicants, excessive use tends to weaken the constitution and to render the consumer more susceptible to disease … the excessive use of these drugs does not cause asthma. . . it may indirectly cause dysentery ... (and) it may cause bronchitis.

 In respect to the alleged mental effects of the drugs, the Commission have come to the conclusion that the moderate use of hemp drugs produces no injurious effects on the mind.... It is otherwise with the excessive use. Excessive use indicates and intensifies mental instability... It appears that the excessive use of hemp drugs may, especially in cases where there is any weakness or hereditary predisposition, induce insanity. It has been shown that the effect of hemp drugs in this respect has hitherto been greatly exaggerated, but that they do sometimes produce insanity seems beyond question.

 In regard to the moral effects of the drugs, the Commission are of opinion that their moderate use produces no moral injury whatever. There is no adequate ground for believing that it injuriously affects the character of the consumer. Excessive consumption, on the other hand, both indicates and intensifies moral weakness or depravity. . . . In respect to his relations with society, however, even the excessive consumer of hemp drugs is ordinarily inoffensive. His excesses may indeed bring him to degraded poverty which may lead him to dishonest practices; and occasionally, but apparently very rarely indeed, excessive indulgence in hemp drugs may lead to violent crime. But for all practical purposes it may be laid down that there is little or no connection between the use of hemp drugs and crime.

 Viewing the subject generally, it may be added that the moderate use of these drugs is the rule, and that the excessive use is comparatively exceptional. The moderate use practically produces no ill effects. In all but the most exceptional cases, the injury from habitual moderate use is not appreciable. The excessive use may certainly be accepted as very injurious, though it must be admitted that in many excessive consumers the injury is not clearly marked. The injury done by the excessive use is, however, confined almost exclusively to the consumer himself; the effect on society is rarely appreciable. It has been the most striking feature in this inquiry to find how little the effects of hemp drugs have obtruded themselves on observation.

 As noted earlier in this chapter, any generalizations from one culture to another must be made with great caution. In this instance, extrapolation to the present Canadian situation would have to span three-quarters of a century as well. In spite of these clear limitations, the thoroughness of this critical inquiry commands respect and the report deserves careful consideration.