Read before the annual meeting of the Western Psychological Association, Los Angeles, April 17, 1970.

 

CLINICAL observations of marihuana users have suggested that there are personality characteristics that are correlated with regular marihuana use. The term "amotivational syndrome" is often heard. McGlothlin and West' refer to "passive, inward-turning, amotivatiotal personality characteristics" as a possible result of marihuana use and point to the need for systematic studies of today's young users. The aim of the present study is to investigate the relationship of some personality factors to extent of use of marihuana.

 

Methods

 

Four groups of marihuana users were compared with two control groups. The user groups consisted of 14 subjects who reported using marihuana almost every day, 19 reporting use once or twice per week, 18 once or twice per month, and 28 less than once per month. The two control groups consisted of 20 subjects who reported never having tried marihuana and 20 who reported having tried it without continuing.

 

The initial pcoi of subjects consisted of 369 students in a basic psychology class at UCLA who completed an anonymous questionnaire and psychological inventory. (The survey was completed by 369 students from a class of 380. This unusually high frequency of response occurred because students could substitute the completed questionnaire for a more time-consuming class assignment.) The number of subjects in each marihuana-use group is the actual number reporting that extent of use. The 20 subjects in each of the two control groups were drawn from the much larger number of students reporting either no use (244) or no continuance of use (56), equated with the marihuana groups for age and class status, but otherwise randomly drawn. Subjects were mainly 18-year-old or 19-year-old freshmen (60%) and sophomores (27%), with 53% female and 47% male. A further description of the subjects is given in the discussion of results.

 

The psychological inventory consisted of four scales (psychopathic deviate, dein-es-4,m, levels of anxiety, and ego strength) derived from the Minnesota Multiphasic Personality Inventory (MMPI),'-.5 a risk-taking propensity scale (RTP),6 a stimulus-seeking scale,7 and nine items specially constructed for the study. (The risk-taking propensity and stimulus-seeking scales are modifications of the originals to make them shorter.) The inventory and questionnaire permitted studying relationships between frequency of use of marihuana and such personality variables as anxiety, depression, rebelliousness, goal orientation, identification with parents, acceptance of the establishment, anger, self-esteem, emotional adjustment, and meaningfulness of life, as well as demographic data.

 

The four marihuana groups were compared with each of the control groups. In addition, subjects reporting use of once per month or more were pooled and compared with the pooled nonusers and infrequent users (less than once per month). Statistical tests used were single classification analyses of variance for continuous variables and x2 tests for categorical variables.

 

Results

 

As indicated, personality factors were studied by means of four MMPI scales, two additional tests, and nine single items (Table). Significant differences among the various frequencies of marihuana use were found for two of the six scales (by single classification analyses of variance) and two of the nine items (by x2 tests). More use of marihuana was related to higher scores on the Stimulus-Seeking Scale and MMPI Psychopathic Deviate Scale, and to "true" responses to the items, "A person should not be punished for breaking a law that he thinks is unreasonable" and "As long as I can remember, I have had more emotional problems than other people."

It was expected that frequency of marihuana use would be related to higher levels of anxiety and depression, greater propensity for taking risks, and lower ego strength. In each instance results were in the predicted direction, but not to a statistically signficant degree. The two other true-false items relating to adjustment had 91% or more subjects claiming good adjustment so that relationship to marihuana use could not he tested. Two special items relating to identification with parental values yielded no significant differences among marihuana-user groups, nor did three other items relating to strong political opinion& lack of goal-orientation, and liking for risks..

 

Sex Was significantly related to extent of marihuana use (2 x 6X2 = 12.67, P < 0.05), the difference from chance expectation being primarily that more males than females reported using marihuana almost every day, and fewer females than males had tried marihuana. (When these two groups were lumped with others in the dichotomous comparison of frequent vs infrequent users, the significance disappeared.) No other demographic variable showed any significant relationship with frequency of marihuana use. Only a few subjects were married or had had military service, and most had decided on liberal arts majors; the groups could not, therefore, be compared on these variables. There was no confirmation of hypotheses that frequency of usage would be related to living on campus or away from family, to having not yet made a career decision, to getting along poorly with parents, or to the role of religion in their lives.

 

The use of alcohol was not related to the use of marihuana. Over one half use alcohol, and 39% of the marihuana users use alcohol and marihuana together, at least occasionally. As would be expected, the ones who use marihuana almost daily are more likely than less frequent users to use alcohol and marihuana together (2 x 5 x2 = 20.26, P < 0.001).

 

Use of other drugs is clearly related to marihuana use (2 x 6 x2 = 64.91, P <0.001). Most of the subjects who have tried other drugs are using marihuana weekly or daily. A total of 100% of the daily marihuana users and 84% of the weekly marihuana users have tried other

drugs, in contrast to 22% of the monthly marihuana users, 18% of the less frequent users, 20% of the ones who have tried marihuana but quit, and 0% of the subjects who have never tried marihuana. The types of other drugs tried (an approximation due to the frequent use

of slang names and descriptions) in order of frequency of mention are: hallucinogens, "downers," "uppers," marihuana-type drugs (hashish, tetrahydrocannabinol), and "hard" drugs (heroin, opillm, ,cocaine).

 

Nineteen subjects (5% of the sample) reported having tried "hard" drugs; all but one were daily or weekly marihuana users. (We do not know how many, if any, did more than experiment with "hard" drugs, nor do we know whether such use followed or preceded use of marihuana.)

 

The extent of use of marihuana in this sample may be of interest, although the sample certainly cannot be considered representative of the campus as a whole. Over a third (36%) of these mainly 18-year-old and 19-year-old students have tried marihuana, and 21% continue to use it. Eighteen percent of the marihuana users use it almost every day, 24% once or twice per week, 23% once or twice per month, and 35% less often than once per month. Over one half of the current marihuana users first tried marihuana before entering college. A total of 64% are using maragtana at a relatively stable rate, 8% are using it more often as time goes on, and 28% (mostly infrequent users) are using it less often.

 

Comment

 

This sample consists of young functioning college students, not dropouts or slum dwellers. There is no support in these student data for hypotheses about impaired parental identification, goal-orientation, role of religion, and liking for risks, any of which variables might well be related to marihuana use in a different segment of the population. The results lend some support to notions that the frequent marihuana-user student tends to be somewhat more hostile or rebellious and tends to seek stimulation. They more often report having long-standing emotional problems and to have less respect for the law. No significant difference was found between users and nonusers in measures of anxiety, depression, and ego strength. We have no data bearing on the important question of whether marihuana use produces the personality differences found or is a manifestation of them. An even more important question is whether frequent marihuana users go on to other drugs or whether some persons are "drug-types" and tend to use both marihuana and other drugs. (A longitudinal study in progress may help to answer both questions. Also in progress is a study aimed at determining the extent of use of marihuana on the UCLA campus and at studying personality differences in a much larger and more representative sample.) We have no data directly bearing on this question, but one finding emphasizing the irnportance of the answer is the marked relationship between frequency of marihuana use and trial of other drugs (especially the 18 daily or weekly marihuana users who have tried "hard" drugs).

 

Most of the statistical differences found did not suggest a simple linear relationship between frequency of marihuana use and the personality variable. Instead the infrequent marihuana user appears to be more like the nonuser or the experimenter (who tried it but did not continue) than the frequent user.

 

Computing assistance was obtained from the Health Sciences Computing Facility, UCLA, sponsored by NIH Special Research Resources grant RR-3. Additional computing assistance was provided by the Western Research Support Center.

 

References

 

1. McGlothlin WH, West 12: The marijuana problem: An overview. Amer J Psychiat 125:370-378, 1968.

2. Dempsey P: A unidimensional depression scale for the MMPI. J Consult Psychol 28:364-370, 1964.

3. Taylor JA: A personality scale of manifest anxiety. J Abnorm Psychol 48:285-290, 1953.

4. Barron F: An ego strength scale which predicts response to psychotherapy. J Consult Psychol 17:327-333, 1953.

5. Hathaway SR, McKinley JD: Minnesota Multiphasic Personality Inventory Manual, revised edition. New York, Psychological Corp, 1967.

6. Kogan N, Wallach MA: Risk-Taking: A Study in Cognition and Personality. New York, Holt Rinehart & Winston Inc, 1964.

7. Zuckerman M, Kohn RA, Price L, et al: Development of a sensation-seeking scale. J Consult Psychol 28:477482, 1964.