Drug Abuse

4. A Selective Review of Studies of Long-term Use of Cannabis on Behaviour, Personality and Cognitive Functioning

C. G. Miles, Formerly Director of Marijuana Studies, Addiction Research Foundation, Toronto, Ontario.

In a sense this paper is probably ten years too soon. In researching the literature it is quite apparent that we do not have enough really reliable studies to completely answer the question implied in the title. In general the research used to assess the state of knowledge in the area falls fairly neatly into several categories. First, retrospective studies where users are asked how long they have smoked and various methods of determining change are used. Second, cross-sectional comparisons, where matched groups are compared on the basis of the amount of time they have been smoking. Third, longitudinal studies where smokers and non-smokers are examined at various points in time. Fourth, long-term experimental and observational studies. The emphasis in this paper is on the third and fourth categories.

All studies have been hampered by the fact that the drug is illicit in almost every part of the world, and punishments for use and possession have been severe. Consequently, smokers have often been loath to admit usage and submit to extensive investigation of the type required.

Only in the last few years have attitudes changed such that governments have been actively promoting investigations into the effects of cannabis, e.g., U.S., Marijuana and Health, Second Annual Report to Congress (1972); Canada, The Commission of Inquiry into the Non-Medical Use of Drugs, Cannabis Report (1972); Britain, British Advisory Committee on Drug Dependence, Cannabis (1968), with the significant exceptions of the Report of the Indian Hemp Drugs Commission (1894) and the LaGuardia Report (1944). The later government reports immediately recognized the paucity of information and research efforts started in earnest. However, political pressures on the investigating bodies reflected the concern of a public uncomprehending of the snail-pace of good science which has filtered through to the scientists.

In preparing this paper, the author had occasion to contact by telephone and in person a number of researchers who had been pressured into presenting either incomplete summaries or tentative reports. Most of these researchers were cooperative and generous with their impressions, but at the same time they have stressed the fact they have incompletely analyzed data or that their studies are still in progress. In some cases funds for the
projects have dried up and whole fleets of ships may be already spoiled for the want of a few pennies' worth of tar.

An alternative title for this paper might be, 'The 'amotivational syndrome' re-examined after a further six years of study'. It will be recalled that the amotivational syndrome is a subtle change in personality manifest in a set of symptoms 'including apathy, loss of effectiveness, reduced drive and ambition, diminished capacity or willingness to carry out complex long-term plans, to endure frustration, to follow routines or to successfully master new material' McGlothlin and West, 1968). To this author studies of long-term cannabis use in which behavioral, personality and cognitive variables have been studied are either implicitly or explicitly searching for evidence which will bear on this hypothesis.

There seem to be few experimental studies which have attempted to investigate the effects of cannabis smoking over relatively long periods of time under conditions where the environment, dosage, and the use of other drugs is known or excluded. The advantage of this type of study is that behaviour can be carefully documented with the minimum of error which is inevitable in retrospective and longitudinal studies, which rely heavily on self support and recall material.

The first comprehensive study was reported in the LaGuardia Report (1944) and was conducted under the auspices of the New York Academy of Medicine. The subjects in this study were primarily volunteers from New York penitentiaries. In all, 72 subjects were studies in groups of 6 to 10, and their stay in the hospital ward experimental setting varied from 4 to 6 weeks. The drug was administered in the form of cigarettes and oral concentrate. For the psychological tests 54 subjects were used; 36 of them were users of cannabis and 18 were non-users. The subjects were tested while under the influence of the drug and when in an undrugged state. Some were tested with 2-5 cc oral concentrates and others with 3-5 cigarettes. A series of psychomotor functions were tested, including tapping speed, grip strength, static equilibrium, hand steadiness, and simple and complex reaction time. Musical
aptitude and auditory acuity tests were also administered. There were almost no effects of the drug on tapping speed and simple reaction time. However, hand steadiness, static equilibrium, and complex reaction were affected adversely by both the higher and the lower doses. Objective time estimation was not affected by the drug, although this effect has been well documented in later acute studies (e.g., Cappell et al., 1972). It is interesting to note that generally the effects of all tests were slightly more pronounced in non-users.

Investigations of cognitive functioning were carried out under similar conditions to the above study. Here tests of learning ability, intelligence, speed and accuracy performance tests, and ability to perform routine tasks were administered. A dose-related effect on cognitive functioning as measured by these tests was noted, but again it was present only under the acute effects of the drug. Once again the effects were more noticeable in non-users than users. It is noted, however, that on some of the simpler tasks, some slight improvement occurred with smaller doses.

Emotional factors and personality structure were studied, giving various numbers of tests to users and non-users. These included vocational interest, self image, emotional stability, self confidence, drive and ambition, suggestibility, and a clinical evaluation. The acute effects of the smaller doses tended to indicate lower drive, objectivity and aggression, while self-confidence increased together with a more favourable self image. At higher doses anxiety and paranoia were evident. It is noted that there were drug state differences between users and non-users. In the undrugged state, the users tended to be more introverted and inhibited, while in the drugged state the users changed in the direction of being more outgoing and anxiety prone. In general the study concludes that there was little difference between users and non-users in intelligence, general behaviour and personality.

There are several problems with this study. First, there is little in the way of statistical evidence presented in the text. Second, the population was drawn from prisons and was under the surveillance of guards throughout the testing. Third, in drug studies the double blind procedure is desirable and was not used. This latter criticism is thought by this author to be of little importance, because in the experience of the writer it is almost impossible to do such studies, since the effects are recognized immediately by the investigator and the subject Niles et al., 1974). Fourth, the doses used are difficult to compare with those such as are routinely reported in the current literature in termsof 2-THC content. However, even with these criticisms it was a commendable effort to study the effects of the drug and drug users experimentally over a longer period of time than had hitherto been attempted. It is interesting to note that no drug-related aggression or psychotic states (Talbot and Teague, 1969) were noted in this study.

In what has become a classic experiment, although perhaps less quoted than it deserves, Williams et al. (1946) investigated the effects of daily administration of pyrahexyl compound and marijuana plant material. The two substances were studied in separate experiments. As in the LaGuardia Report, the subjects were all prisoner volunteers, who in this instance were serving sentences for violation of the Marijuana Tax Act.

Pyrahexyl compound is a synthetic substance said to have similar effects to that of marijuana, with assumed pharmacological similarities. In general the methods, measuring instruments used, and effects were similar with both substances. Only the marijuana smoking study will be reviewed here.

Six subjects were studied in a research ward of a hospital. The period of investigation ran 7 days preliminary observation, 39 days smoking ad libitum, and 7 days post smoking observation. Although the potency of the cannabis was not assayed, it was assessed by these experienced smokers as 'good weed'. The average number of cigarettes smoked per day was a quite remarkable 17, with a range of from 9 to 26. An exception was one subject who limited himself to one cigarette per day. There was an overall trend towards increasing dosage.

It is difficult to assess the size of the cigarettes, but an examination of the two figures giving dosage and number of grams smoked suggests that the cigarettes were either experimentally varied in size or the subjects were able to roll their own.

The psychological test material was obtained when the subjects were thought to be high during the two weeks after smoking had begun, during the pre-smoking period, and in the post-smoking period. The Rorschach, Stanford-Binet, MacQuarrie Test for Mechanical Ability, Seashore Measure of Musical Talents, and Muller-Lyer Illusion tests were given.

Pre-smoking, the Rorschach showed all subjects but one had patterns which were immature and restricted, whereas during smoking the results suggested fewer, but more elaborate patterns. Intellectual functioning was somewhat impaired during the smoking period, but returned to baseline in the post-smoking period. The MacQuarrie Test showed an increase in speed but a loss in accuracy. No improvement in musical ability was reported, although subjects thought they made better discriminations. Judgments in the Muller-Lyer Illusion Test were inconsistent during the smoking period, suggesting lack of motivation and carelessness. It should be remembered that these tests were all done while the subjects were thought to be intoxicated, and after only two weeks of smoking. They can in no way be construed as being indicative of long term effects.

Of greater interest in this study are the general clinical observations, such as an increase in sleeping time, general lassitude, the incapacity of subjects to apply themselves to the achievement of self set goals, or externally set goals, social deterioration and lack of personal hygiene. However, none of the subjects showed anti-social behaviour or psychotic reactions during the study. This presents a picture very much like that of the amotivational syndrome. Also of interest is the fact that no objective evidence of an abstinence syndrome after the abrupt cessation of smoking was observed, although the subjects themselves reported that they were somewhat 'jittery' for a few days. The authors report the general conclusion of a return to baseline testing conditions where tests were administered.

Yet a different approach was used by Mendelson and Meyer (1972). figain they used a hospital ward setting, and their subjects were confined for a 31-day period. Subjects were 10 heavy and 10 casual users of cannabis. Heavy users were defined as subjects with 2 to 5 years experience of marijuana smoking, and who smoked daily for at least one year prior to the study. Casual users were defined as having a current smoking pattern of 1 to 4 sessions per month. These two groups were run separately. The subjects typically were multiple-drug users, unmarried, and unemployed. The groups differed primarily in the quantitative patterns of drug use. Both groups were of above average intelligence. The heavy user's tended to have started alcohol and marijuana use at a slightly earlier age, although alcohol use in both groups was said to be infrequent.

The groups were matched on total years of marijuana use, but the heavy users tended to smoke a mean of 33 sessions per month, as opposed to casual users, smoking a mean of 7.7 sessions per month.

The setting appears to be rather similar to that described in Miles' study Miles et al., 1974), with recreational facilities available, and relatively high security. In both of Mendelson's studies a pre-drug period of 5 days was given; a 21-day period of access to marijuana; followed by a 5-day non-access to marijuana period.

The variables of interest to this paper were:

1. Work-contingent operant acquisition and free choice marijuana consumption patterns.

2. Measurements of mood states.

3. Individual and group behaviour observations, clinical and psychological evaluations.

Subjects were given an operant manipulandum, which was available to them at all times. By manipulating a bar, they could accrue points which could be used to purchase tobacco during all periods of the study and
also marijuana cigarettes during the smoking period. They could also accumulate points which could be converted into money at the end of the study. The operant bar consisted of a 4-digit hand counter, and the operant task
was simply to accumulate points on the counter by pressing the bar. Payment for accumulating points was at the rate of one cent for 60 points, but there was a maximum limit on their earnings of ten dollars per day. A pack of cigarettes cost 50 cents, and one marijuana cigarette cost one dollar.

The marijuana used in these studies varied from 1.8 to 2.3 per cent THC, and each cigarette contained approximately 1 gram of material. The counter readings on the operant manipulandum were recorded every two hours. All
subjects earned the maximum reinforcement points every day. This contrasts with results obtained in Mendelson's alcohol research, in which subjects showed a cessation of work output when they were consuming alcohol. There was no marijuana-related change in the pattern of work, and subjects often performed high work output while they were actually smoking marijuana. There was a wide range in the amount of consumption among the casual users, ranging from an average of one cigarette a day to an average of 6.2 per day, although there was an overall 46 per cent increase in the use of marijuana during the fourth quarter of the experiment as compared to the first quarter. In the heavy user group, average daily consumption ranged from 3.6 cigarettes to 8.7 cigarettes, and this showed an overall average of 37 per cent increase in the amount smoked in the fourth quarter of the drug period as compared to the first quarter.

A 10-point rating scale showed that there was no correlation between 'highness' and smoking day. Thus there appeared to be no tolerance to subjective effects. Over the period of the study, the casual smokers indicated an increase in negative mood states, such as anxiety, hostility, depression, and a decrease in positive mood states, like friendliness, carefreeness, etc.

Digit span tests, which were administered regularly, showed a steady performance increment. It should be noted here, however, that subjects were paid five cents for each series of digits reproduced correctly, thus they were financially motivated to increase efficiency, and this motivation was not impaired by the amount of marijuana smoked. Cognitive functioning as measured by the Wechsler Adult Intelligence Scale showed no marijuana-related changes over the course of the study.

It is of interest to note that the subjects rarely chose to smoke alone. Less than 6 per cent of the marijuana consumed by either group was smoked in a place where other subjects were not present, although the heavy users tended to join groups more rapidly once smoking had started, and they also tended to be more verbally withdrawn than the casual users during the smoking.

Mendelson and Meyer's results suggest no evidence of the amotivational syndrome. However, this may be due to the fact that the task assigned as an earning task was so simple that it would not be impaired by marijuana. Moreover, since there was a ten dollar daily limit on the amount of earnings, it could be that realistic baselines were not established early in the study. That is to say, these results could be interpreted by saying that the task was
so well within the grasp of the subjects that the ingestion of marijuana, even in heavy doses over a large number of days, would have no effect in decreasing the efficiency or output of this task. Consequently, these results must be viewed with caution when relating them to the amotivational syndrome.

A more recent study in which a double blind procedure was used was conducted by Frank, Epps and Rickles (1973). Here the acute and cumulative effects of daily cannabis smoking were studied. The subjects were 21 healthy college educated males who were hospitalized for 36 days. All were marijuana smokers. The design of the experiment included 4 days of pre-test when no smoking occurred, 28 days of continuous daily smoking, and 4 days of post smoking testing. The subjects were randomly distributed to 3 groups, which were given marijuana cigarettes weighing approximately gram. According to which group they were in, the cigarettes were placebo, 1 per cent THC, or 2 per cent THC. Among the tests of interest in this paper were a test for subjective estimation of 'high' (Katz-Waskow SDEQ), Digit Span Test, Word Association Test, Clomputation Test, MMPI, WAIS, TAT, and Holtzman Inkblot Test. Daily mental status and behavioural observations were also made.

These authors noted no bizarre behaviour, nor do they report any cumulative effects, withdrawal, or tolerance effects as measured by the psychological and clinical test instruments. They do note that the placebo subjects showed some rise on physiological indices of anxiety, which they assume was caused by the stress of confinement in hospital. Thus, the marijuana may have had a tranquillizing effect on the other two groups. They note some impairment on mental performance tests, some elevation of moods, but put little emphasis on this point.

The data from this and other similar studies are still incompletely analyzed (Frank, 1974, personal communication). Although the experiment was not designed specifically to generate evidence of the amotivational syndrome, some hints might have been obtained on tests like TAT or the MMPI, but no changes were intimated.

It should be noted that in a pilot study by Frank (1973) that cigarettes with 4 per cent THC produced some disorganized thinking and paranoid ideation. One subject dropped out of the experiment because of paranoid and psychotic tendencies after only 3 days of smoking.

A somewhat different approach was taken by Miles et al. (1974). They designed an experimental framework which they called a 'microeconomy'. The subjects in this experiment were 6 healthy young marijuana smokers. All except one were unemployed at the time they volunteered for the experiment. They signed a contract that they would stay in the experiment for 70 days, whereupon they would receive a bonus of 200 dollars. The essential set-up was a
hospital ward where they were given a task for which they were paid in cash-equivalent tokens. The task was the construction of llj inch wooden stools which were pre-cut and held together by friction fit. A sea grass top was then woven into place.

Essentially the subjects were offered a job and out of their earnings they had to pay for all entertainment, food, recreation, and clothes; liquor was available at street prices from a store where other goods such as cigarettes and toiletries were available. All other goods were ordered out for. The nursing staff dressed in street clothes and had been trained in interpersonal influence techniques. They were then instructed in a non-involvement role, restricting their interpersonal behaviour with the subjects to a neutral response to subjects' requests for transactions. Behaviour of all subjects was checked and recorded every half hour. Subjects were kept on the ward under high security conditions. On occasional walks, they were always accompanied by a staff member.

The design of the experiment was as follows. For the first two weeks no cannabis; during the third week they were allowed to purchase cannabis ad libitum at street prices. During the following 28 days they were required
to smoke cannabis and could purchase more at street prices should they so desire. For the following week they returned to a free purchase only situation, and in the final two weeks cannabis was withdrawn. Full medical monitoring was carried out with routine examination, blood and urine testing, etc.

All of the subjects' transactions, production, spending and savings were recorded. The MMPI and Ravens Matrices Tests were given only as screening devices, although in three later and longer studies a battery of personality and intelligence tests was given at regular intervals during the studies. Unfortunately the results from these studies are not ready for reporting.

Route of administration was by smoking natural plant material - one gram cigarettes each containing 8.5 mg THC. During the mandatory smoking period the dose was 2 cigarettes, containing a total of 17 mg THC. All smoking was done under supervision.

One of the more interesting aspects of the study that should be noted was that while the subjects were all very experienced cannabis users, they were not disinterested in economic gain. After only 8 days in the study they took unanimous action to negotiate a pay raise from $2.00 to $2.25 per unit of production. They threatened to leave the experiment if they were not granted this raise. The second round of negotiations occurred 28 days later; the threat to leave was repeated. Production and savings had been declining, and the amount of time spent in passive entertainment was increasing. The complaint was that the high amounts of marijuana they were required to smoke did not allow them to produce. However, when the price per unit was raised to $2.75 the picture changed dramatically: production rose, less time was spent in entertainment, and less marijuana over and above the required 17 mg THC was smoked. Savings increased, although spending tended to remain stable throughout the experiment. A small but consistent positive correlation between alcohol consumption and marijuana consumption was noted. If the drop in production can be seen as evidence of the amotivational syndrome, it can certainly be overcome by making other rewards greater, in this case, economic incentives.

In relation to the amotivational syndrome it should be noted that the efficiency (the amount of time taken to produce each unit of production) did not suffer even when production was low. In fact, a steady improvement
in efficiency was noted over the length of the experiment. Moreover, no changes in time spent sleeping were noted, nor was the amount of time spent in toilet and grooming behaviour related to changes in marijuana dosage. In
this context, '... the general lassitude and indifference which resulted in carelessness in personal hygiene...' noted by Williams et al. (1946, p.20), was not observed, nor was it noted that the subjects showed evidence of social deterioration such as that associated with '... opiate addiction and chronic alcoholism ...' (Williams et al., 1946, p.20). Since, however, we have no knowledge of the doses of THC in the marijuana administered by Williams et al., this lack of replication may well be explained by the fact that his doses may have been higher. A psychiatric assessment at the beginning and at the end of the study revealed no changes in mental status.

Truly long-term studies of a longitudinal sort are rather rare in the literature. There are probably several very good reasons for this: as Robins, Darvish and Murphy ( 1970 ) point out, there has not been enough time to evaluate the long-term effect of marijuana on middleclass white adolescents, which could be interpreted as a social comment on current concerns. Moreover, there are probably very good methodological reasons as to why these studies have not been done. It is extremely difficult and time consuming to contact and re-contact at a later date.

Robins, Darvish, and Murphy tackled the problem in a rather novel way. They randomly selected and contacted names from old elementary school records. In this sample there were 76 users and 146 non-users of marijuana, all black males of normal or better intelligence. The authors point out that the young black population was using marijuana long before the middle-class white adolescent population. In this sample were 22 subjects who reported only marijuana use, and who started taking the drug before the age of 20. This is an important group, because marijuana use is apparently uncomplicated by other drugs.

They used a questionnaire technique designed to find out the effect of marijuana use on education, sex, occupation, criminality, violence, and alcohol use. They found that only 40 per cent of the marijuana users graduated from high school, as compared with 66 per cent of non-users. With regard to sex, marijuana users tended to show no differences from non-users in terms of age at marriage or length of courtship, but they did tend to exceed non-users in extramarital experience, and the number of illegitimate children they claimed to have fathered. The adolescent users tended to have lower prestige level jobs and much more unemployment. In terms of criminality, although marijuana users proved overall to have arrests as rarely as non-users, the marijuana only group tended to have more adult arrests for offences against property or persons. They also tended to admit to having more violent dispositions. All of the marijuana-only users who started using the drug in adolescence also used alcohol, but drinking preceded the taking of marijuana. When those subjects who used marijuana and alcohol in adolescence were compared to those subjects who used alcohol alone, both groups had a diagnosed rate of alcoholism four times greater than that in the drug free group.

Although they conclude that marijuana only users showed better social adjustment than subjects who used other drugs or marijuana plus other drugs, they state, 'Every attempt to rule out a direct harmful effect of marijuana use has failed.'

Although these authors state that they had no reason to believe that other drug use was being concealed, the present author's experience with marijuana users suggests that concealment of other drug use is frequently encountered. If this were the case, it would somewhat contaminate the results of this study. A further problem with studies of this nature is also the fact that it is very difficult to establish length and frequency of use and the potency of the drug used.

The results reported by Robins, Darvish, and Murphy contrast rather strongly with those of Hochman (1972). Although Hochman's study is characterized as a longitudinal drug research project, which was set up in 1969, the results of the second stage of the study are not yet available, at least to this author's knowledge. Hochman sent 2200 students a 30-page questionnaire and got a 64 per cent return. Of these, 25 per cent volunteered to be tested and interviewed further. They tested and interviewed every fourth one. Their analysis compared three categories of students: experimental smokers; occasional, i.e., up to two years, smokers; and students who used cannabis three or more times per week.

The acute effects of marijuana intoxication reported tended to agree with those reported by Tart (1970), and are well known. They report, as does Smart (1971), that there is a significant correlation between the use of marijuana and a tendency to experiment with other drugs. With regard to motivation, they report that a higher percentage of chronic users than non-users plan to go on to graduate school. There were no differences in the feelings of life direction, or in difficulty in choosing a career, although chronic users showed a significant difference in the number of interruptions in college study. Even so, they say that overall grade averages of users were slightly higher than non-users, but not statistically significant. With regard to the law, the only difference between users and non-users was that users had significantly more traffic offences. Marijuana use did not affect age at marriage, number of times married, number of times divorced or separated, number of children, or marital adjustment, sexual adjustment, or incidence of extramarital sex. However, users tended to have had sexual experiences earlier, have more of them, and, not
surprisingly, have a higher incidence of venereal disease. Although marijuana use did not affect the age at which the first job was taken, the total number of full-time jobs, and current employment, three times as many users as non-users quit their job because it was 'dull'.

Although Hochman reports that he found no evidence of an 'amotivational syndrome', he also paradoxically reports that twice as many users as non-users could not decide, or did not know, what their plans were for the next five years. He reports also that the groups did not differ with regard to major or minor illnesses or any degree of psychological morbidity, or history of emotional illness, psychiatric or psychological therapy. Chronic users tended to be far more politically active than non-users. It is of interest to note that chronic users report that they reduce or eliminate their use of marijuana when visiting rural or small town environments, indicating that the tranquillizing effect of the drug may be an important element in reducing the pressure of city living.

A study by McGlothlin, Arnold, and Rowan (1970) is unique in that it used a sample of subjects who typically first tried marijuana in adolescence, 20 years prior to the study, and subsequently used it on a regular basis for a minimum of 2 years, and who also, during the 1955- 1961 time period, took LSD in a medical setting, half in psychotherapy, and half as volunteers for experiments.

The data reported in the paper consist of comparisons between this group and two other samples from the LSD group of approximately the same age, sex ratio, education, and proportion in art-related professions.

The majority of subjects who used marijuana heavily as adults began its use in adolescence. Only one of the 17 respondents introduced to marijuana during 1961-1968, typically in the 30 to 40 age range, has ever used it on a regular basis. Most middle-class persons during the time period in this study were never exposed to the drug. Others were deterred by concern over the legal hazards. Another variable of importance is occupation - among the middle class, people in the entertainment field and other art-related professions were much more inclined to find marijuana to their liking than other groups. They were more likely to use it while working, and to report that it either had no effect or that it enhanced their performance.

The most consistent correlates of marijuana use in these subjects were a continuing involvement in the various means of altering consciousness, and an unstructured and relatively unstable style of life.

The search for altered states of consciousness was indicated by the tendency to use or at least experiment with a wide variety of drugs other than marijuana, but it is also evident in various non-drug use areas. Marijuana users were significantly more prone to non-drug induced regressive states as measured by a hypnotic susceptibility test. They were also much more likely to believe in the validity of astrology, ESP, etc., and were likely to have practised one or more disciplines such as meditation, yoga, or Zen for a period of several years.

In terms of lifestyle, they tended to prefer a high level of stimulation, uncertainty and risk, instead of security and structure. They evidence more than average work and residence instability, they are especially unlikely to maintain a permanent marriage, they are more alienated from a socio-cultural standpoint, but not in a personal sense, i.e., their alienation does not take the form of pessimism, self contempt, and barren interpersonal relationships.

As indicated by Robins, Darvish, and Murphy, the user is more likely to have had a history of heavy alcohol use, but strangely, not especially attracted to sedatives and tranquillizers.
Other patterns of use include periods of months or years in which marijuana is used virtually to the exclusion of alcohol, or vice versa. Regular users of marijuana in this study cite the relaxing or tranquillizing effect as
a major motivation for using marijuana, as well as euphoria.

However, the results also tend to support the position that marijuana abusers would be drawn from the population who use, or would use, alcohol to excess. From the behavioural standpoint, there is no simple relationship of substituting one drug for the other. The majority of marijuana users reported that their use of marijuana reduced their total consumption of alcohol. Although the authors made no systematic attempt to explore harmful results of excessive use of alcohol, several respondents reported their use of alcohol had been considerably more disruptive than their use of marijuana. Specific problems associated with excessive use of alcohol were drunken driving, assaultive behaviour, and an inability to work. The degree of dependency was felt to be greater for alcohol.

The authors conclude that if a white, middle-class, middle-aged person began using marijuana as an adolescent some twenty years ago and continued on a regular basis for several years, there is a high probability he has a history of fairly heavy use of the intoxicant that is somewhat more socially approved, in other words, alcohol. From the results of this study, it does not seem likely that marijuana use would replace alcohol for many persons, however, the overall consumption of alcohol might be reduced.

A study by Sadava (1972) points out the importance of not using personality characteristics exclusively as predictors of cannabis use. He argues that the individual differences approach exclusively is inadequate for explaining cannabis use. He cites, for example, anxiety and alienation as correlates of student drug use, but not exclusive characteristics. Sadava gives great weight to the Becker (1953) hypothesis, where marijuana use seems to be a consequence of social experience, or social learning. His basic conceptual framework is field-theoretical, and he refers to cognitive as well as to behavioural learning. Basically, he views deviant behaviour as consistent with other behaviour in a more general social-psychological framework.

In this study, Sadava tested a total of 319 subjects in the freshman week of September, and they were again tested the following March. He was fortunate enough to retain 89 per cent of his original sample. Of the original 319, 110 had used cannabis before college orientation week (the user group); 168 remained as non-users throughout the college year (the non-user group); and 41 of the non-users were initiated to cannabis during the college year (focal initiative group). The data for males and females were consistent, and therefore were combined.

His basic measure was the extent to which a subject believed in internal versus external control, i.e., the extent to which a subject sees negative and positive consequences happening to him as contingent on his own behaviour (internal) or upon luck, or powerful others (external). Thus cannabis use, in a sense, may be a functional substitute for defensive externality. A basic orientation of this research then, was to examine the personal meaning of use or abstinence in terms of gaining positive satisfactions or avoiding negative consequences. Therefore, high positive function scores and low negative function scores should predict cannabis use as a selected deviant behaviour. Other factors, such as religious affiliation, social class, and ethnic background, did not predict marijuana use.

In summary, it was hypothesized that the users relative to non-users should have lower expectancies in the area of academic recognition, social love and affection, and high expectancies for independence and internal control orientation. Moreover, they should have positive and fewer negative functions for use. It was also postulated that users should have greater ethical tolerance for use and greater social support. If these variables are good predictors, they should differentiate initiates from non-users prior to their initiation to cannabis use, and the initiate versus non-user distinctions should be increased subsequent to initiation.

The author concludes that both personality dispositions and social environmental variables are important in predicting whether a college student will begin to use cannabis in college or not. One interesting point arises from this research, in that the expectations for academic recognition prior to college orientation were somewhat lower for the user group than the non-users, but this difference disappeared at the time of the second testing in the spring. The postulated lower expectancy for social love and affection was not shown; on the contrary users in both fall and spring testing exhibited a high expectancy.

Within a similar theoretical framework, Jessor, Jessor and Finney (1973) studied a student population consisting of junior high, senior high and college students. These authors were concerned to place cannabis use within a more general social psychological framework. In particular, they were using as a background the social learning theory of Rotter (1954) and Rotter, Chances and Phares (1972). The report is a part of a larger, ongoing study of socialization problem behaviour in youth. They point out that the personality-environment interaction has with very few exceptions been ignored by most drug research, and are concerned to get away from the descriptive or epidemiological standpoints. They conceptualize marijuana using behaviour as probably only one of a number of problem behaviours.

In this background, four hypotheses are advanced;(i) that marijuana use should co-vary with other kinds of problem behaviours; (ii) variation in marijuana use should be systematically related to variations in the personality and perceived environment; (iii) the onset of marijuana use among non-users should be predictable from initial differences on those same personality and social variables; (iv) irrespective of initial differences, those who begin marijuana use during this period should manifest greater relative change of the personality and social variables in the theoretically expected direction. In general then, marijuana use is seen like any other learned behaviour,
as a functional outcome of the interaction of personality, social and behavioural attributes.

A theoretical summary profile of the social psychology of the student marijuana user put forward by Jessor, Jessor and Finney (1973) is that first, there should be greater instigation to use, stemming from higher value on independence and lower value on achievement, and lower expectations for achievement. Second, there should be less belief in controls against use, and greater social criticism and alienation. Third, less personal controls against use, greater tolerance of transgression and less religiosity. Fourth, there should be greater environmental support for use, greater peer-orientation, models and supports; and fifth, greater experience with other behaviours of a 'problem' or 'problem prone' nature.

The sample from this study was asked to take part in a 4-year study of personality and social development in youth. It was a large sample and they were given extensive personality testing plus a marijuana-behaviour report, which was a 4-point scale of involvement. The cross-sectional analysis gave support to hypotheses(i) and (ii). Users valued achievement less and independence more than non-users, and they also tend to have lower expectations for achievement. In terms of belief structure, users tended towards greater alienation, and were more socially critical. In terms of personal controls, users were more tolerant of deviance and showed relatively less religiosity. In terms of perceiving environmental controls, the users saw less compatibility between peers and parents, and acknowledged that their peers had greater influence on their views than their parents, thus there were more models, pressures, and peer approval for drug use. These findings held for the junior high school, senior high school, and college samples, and in general held across sex and intensity of use. In the longitudinal analysis, which involved retesting after a year, hypotheses (iii) and (iv) were tested. The results showed first, that among non-users there are initial differences among the variables, such that they are predictive of the onset of. marijuana use over time. Second, there was a greater relative change in the problem prone direction for those who share user status than for those who remained non-users. These differences held for both males and females. However, as the authors point out, with regard to hypothesis (iv), it is not possible to determine whether changes in the variables precede or follow the behavioural change. There were certain differences in the college population with regard to hypothesis (iii). The proposed variables did not predict the change from non-user to user status. The authors suggest that this may be in part explained by the high rate of use amongst the college sample: in this case, 70 per cent. They note that the variable of social criticism was much more important at the college level, suggesting a greater idealogical role of marijuana use in college and less of a role in coping with failure, as may be the case with marijuana use in high school. This study (Jessor, Jessor and Finney, 1973) is of particular significance because of its methodological soundness and its attempt to relate a general social-psychological theory to drug using behaviour. Unfortunately, little information is given on the extent of multiple drug use and its relationship to the magnitude of changes.

Although in North America it is difficult to find populations who have been using cannabis for long periods of time, it is possible to find communities where large numbers of people have been chronic users of cannabis.
Of the more notable work in this area are the investigations directed by Rubin and Comitas (1972) from the Research Institute for the Study of Man. As Rubin (1973) points out, it is important to study the cross-cultural aspects of cannabis smoking, not only because it is possible to find chronic smokers using extremely high dosages, but also to see whether some of the effects which are reported in North America and other parts of the world are culturally conditioned, or whether they are a direct consequence of pharmacological effects.

Bearing directly on the amotivational syndrome hypothesis is the work of Schaeffer (1972), reported in Rubin and Comitas (1972). The general air of this research was to find out the relationship of cannabis smoking to agricultural pursuits, to the exploitation of land resources, and to exchange relationships, and its effect on the economy. They were particularly interested in learning whether acute and cumulative effects of the use of cannabis had any effect on energy expenditure during work in agriculture.

Their method was to observe and videotape agricultural work in progress. They were able to observe the number of times per day and they were also able to get estimates of the g-THC content of the material smoked. An important measure in these studies was the number of kilocalories required to complete a task when smoking and when not smoking. They were able to study heavy users who smoked 3 to 8 times daily, smoking as much as one ounce of cannabis; and very light users who use cannabis less than once a week. Jamaican cannabis is usually of very high potency and has been reported as high as 7 per cent THC.

In general they report that the use of cannabis is related to effective alterations in the rate and organization of movements, and the expenditure of energy during work. Most of the smokers enacted more movements per minute and they tended to expend more kilocalories per unit of space immediately after cannabis use. However, between 20 to 40 minutes after smoking, the alterations in behaviour appear to return to normal, and between 80 and 140 minutes, feelings of fatigue were often expressed in movement. Dose, frequency of use, and psychological set during use are all important, together with the situational context.

The results of the micro-analysis of case studies were summarized as follows:
(i) Use of cannabis is related to effective alterations in the rate of organization of movement and expenditure of energy.
(ii) Behavioural changes related to light or moderate use are not significant in agricultural pursuits over an extended time period. Behavioural changes related to heavy use are significant in agricultural pursuits over extended time periods.
(iii) Alterations related to both moderate and heavy use are appropriate to social cohesiveness during work in group situations.
(iv) Total space covered, or amount accomplished, or in number of plants reaped, is usually reduced per unit of time after smoking. The number of movements per minute is often significantly greater after smoking, as is the total number of movements required to complete a given task.

Within the same series of studies, Beaubrun and Knight (1973) hospitalized 30 chronic users and 30 matched control non-users for 6 days. All of the subjects were male. Chronic users were defined as those who had smoked daily for not less than 10 years. The object of the study was to make psychiatric and psychological comparisons. On the behavioural and psychological variables, there were no differences between the two groups in the incidence of mental illness, alcoholism, or number of arrests. There were also no differences between the groups on the Eysenck Personality Inventory, or extroversion or neuroticism scores. A mental status examination revealed no significant abnormalities and no difference in the use of other drugs. The work record of each group was very similar, but this may be because the sample was made up of subjects who had occupations where there is little social mobility. Two important differences between the groups appear to be worth mentioning: one is that the family history of mental illness, excluding alcoholism, was significantly greater in the sample of smokers and not surprisingly, the smokers had reported more hallucinatory experiences, although these were when they first used the drug.

These reported effects (Beaubrun and Knight, 1973) are consonant with the work of Bowman and Pihl (1973). Bowman and Pihl did two studies which were almost identical, and were designed to study specifically the psychological effects of chronic use of marijuana on intellectual functioning. The experimental group of subjects were typically smoking daily, and they were smoking material which had 4 to 5 per cent THC content. The users in the sample had typically begun smoking around about 12 years of age, and had been using cannabis for 164 years. The mean consumption per week was 167 grams, which is the equivalent of 23 standard cigarettes per day. Matched controls of non-smokers were used in both studies.

Both groups were tested on three sets of tests. The first was concerned with physiological, sensory, and perceptual motor functioning. The second set measured concept formation, and abstracting abilities. The third set was comprised of a number of memory tests. They found no differences between the groups. It is important to note that the subjects were required to be not high at the time of testing. It is worth mentioning that they point out that North American users suggest the drug enhances their sexual pleasure or performance, while users in this study scorned the notion, and gave the impression that they regarded this as a perverted use
of the drug. The amotivational syndrome was denied by the subjects here, because the subjects often smoked specifically, as indeed in India, to provide energy and strength in order to accomplish particularly heavy tasks. They underlined Rubin's point (1973) that many findings may be cultural artifacts, and that the effects of the drug may be very much controlled by cultural expectations. They also comment on the possibility of tolerance and cite examples of people who have consumed as much as 5 ounces of cannabis in 5 hours, showing only minimal behavioural effects.

Acknowledgement

The author wishes to acknowledge the assistance of Janet McDougall and Frances Theodor, research assistants, and Barbara Vary and Evelyn Wollis, for their help in preparing the manuscript.

REFERENCES

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Bowman, M. and Pihl, R.O. Cannabis: the psychological effects of chronic heavy use. A controlled study of intellectual functioning in chronic heavy users of high potency cannabis. Psychopharmacologia, 29, 159- 170 (1973).
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Jessor, R., Jessor, S.I. and Finney, J. The social psychology of marijuana use: longitudinal studies of high school and college youth. Journal of Personality and Social Psychology, 23, 1-15 (1973).
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Miles, C.G., Congreve, G.R.S., Gibbins, R.J., Marshman, J.A., Devenyi, P. and Hicks, R.C. An experimental study of the effects of daily cannabis smoking on behaviour patterns. Acta Pharmacologica et Toxicologica, Supplement (In press, 1974).
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DISCUSSION

Dr Edwards was concerned to define what is meant by 'amotivation' in comparison with normal behaviour. Dr Connell observed that in England in the late fifties and early sixties, before cannabis use had become widespread, a syndrome had been described entitled the 'lying-abed syndrome' in adolescents. This seemed to
be a feature of adolescent emotional development and was not at that time related to cannabis. If cannabis had been taken the behaviour might well have been attributed to cannabis. Dr Edwards stressed that amotivation means lowered motivation rather than no motivation.

MATCHING

Professor Paton asked about matching control and experimental groups. 'If one takes a group and matches them with another, one may inadvertantly mask one of the effects one is looking for. If you suspect that amotivation may be an effect of cannabis, and that amotivation may affect income, social class or educational level, then by matching for these factors you delete the effect you are looking for. Or we could find ourselves investigating the possibility of, say, liver damage due to drug use, and matching the control and experimental groups for equal health. Should one leave out of the matching procedure any factor which the drug might affect?'

If it is possible to match the experimental to the control group before drug use occurs, then this problem is evaded. This is, however, only possible in experimental laboratory studies and not in longitudinal studies, since the criterion for placement in the control or experimental group is the drug behaviour. In longitudinal studies one can only collect information about individuals in a population before drug use, and then after drug use, try to match some of the users with some of the non-users on the basis of the previously collected information, discarding unmatched individuals.

HOSPITALISATION EFFECTS

Dr Leuw and Mr Hasleton raised questions about the effects of being hospitalised. Quite apart from effects of being constantly observed in rather artificial circumstances, there is the question of the picture of themselves as cannabis users that subjects might be motivated to present.

Dr Miles explained that the staff were trained in techniques of nonverbal communication and influence, and then instructed to monitor their own behaviour and to minimise their influence on the subjects. It was agreed, however, that not all such influences can be completely controlled, and that meanings of the situations, which may have implications for behaviour, cannot be equalised for all subjects.

Dr Rubin stressed the need for field studies of users in their natural environment, in order to understand the Gestalt of social behaviour of which cannabis use is a part. Sociological and anthropological techniques of data-collection helped to fill out and place in context the results of experimental and clinical studies.

SEX DIFFERENCES

Dr Miller pointed out that 'until very recently, nearly all the studies of cannabis use and effects were based on male college students, male psychiatric patients, male prisoners, and male white rats. Typically, if general information about the species is sought, males are used. Almost without exception females have only been studied if some 'specifically female' characteristic is in question. What comparisons were you able to carry out, and what differences did you observe between males and females?' Dr Miles responded that 'we were pretty unsuccessful in comparing males and females, because female behaviour patterns were so different. For example, they were very generous, giving their money away. And in connection with sex; the men did not care at all, but the women felt extraordinarily deprived and they used to act out. We got a call at 4 o'clock in the morning complaining that the girls were acting out at the windows, naked. These were the main differences; also they didn't smoke so heavily.'

CANNABIS AND MOTIVATION

Dr Rubin gave some more information on her study of Jamaican agricultural workers' use of cannabis. Cannabis was used in relatively high doses to get energy for arduous tasks, and for weeding, sawing, and cane-loading cannabis use was associated with harder working. This did not always result in a greater throughput of work,
or greater efficiency. In spite of the higher expenditure of energy in weeding, there was a drop in efficiency of sowing, and current analysis of videotapes was investigating a possible increase of efficiency of can-loading.

Participants were interested to hear that Dr Miles' experimental subjects held a strike and forced renegociation of their system of rewards. Asked about this 'strike', Dr Miles said: 'They threatened to leave.

Here you are, you have a staff of 25 people and a hospital floor. What can you do? The strike regulations lasted two days. I put them off one day and they were going to leave the next if they didn't see me.'

In general, there was agreement that there was no clear evidence that cannabis in and of itself affected motivation in a particular way.

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