Method
Results and discussion
Author: Ian HINDMARCH, Ian HUGHES, Rosemarie EINSTEIN
Pages: 27 to 36
Creation Date: 1975/01/01
Research in the U.K. concerned with measuring attitudes to drug use in student populations (Binnie, 1969; Brooke-Crutchley and Young, 1971; Hindmarch, 1970, 1971) has concentrated upon the attitudinal parameters of illicit and non-medical drug use and little attention has been paid to the attitudes associated with the use of alcohol and tobacco. However, Blum (1969), Bogg et al. (1968) and Goode (1969; 1972) have shown that tobacco usage and the use of all illicit drugs are closely related empirically. Smart (1970) Lavenhar (1972) and Smart and Fejer (1972) have shown that both parents and peers of cannabis and other drug users are more likely to be smokers of tobacco. Individual interviews of 153 admitted drug users (Hindmarch (1970)) showed that cannabis users were heavy cigarette smokers, while Weitman et al. (1972) claimed that the use of alcohol and tobacco correlated with the use of other illicit drugs especially cannabis and McKay et al. (1973) concluded that "drug users" were males who smoked and drank alcohol more frequently than the norm. More recently, Einstein et al. (1974), found that chronic users of cannabis tended to be also heavy tobacco and alcohol users; and they showed that the tendency to "try" cannabis was also associated with a heavy use of alcohol and tobacco. This previous research illustrates the close interdependence between the use of cannabis, alcohol and tobacco in certain groups of drug users.
In order to investigate the possibility of a similar interrelationship between the attitudinal parameters associated with drug using behaviour this present paper reports on a variety of attitudes held by users and non-users of the three drugs; alcohol, cannabis and tobacco. A special investigation of attitudes towards cannabis is made to test the cognitive consistency model which hypothesizes that the attitudes an individual drug user holds will be congruent and compatible with the behavioural milieu surrounding him.
One thousand names were selected at random from the lists of enrolled students at a provincial university and a self administered questionnaire, together with a covering letter and guarantee of anonymity was mailed to each individual. Personal details (age, sex etc.) were collected as well as histories and patterns of the use of alcohol, tobacco and cannabis. The questionnaire also contained a full semantic differential rating scale for each of the three drugs under consideration and a bank of attitudinal statements derived from previous work with undergraduates (Hindmarch (1970, 1972a)).
The techniques used for the measurement of attitudinal variables was based upon checking a 10 cm line drawn between two antonyms or semantic opposites. The method is essentially that of Osgood's Semantic Differential Technique (Osgood et al. 1957) but with 10 cm response lines in lieu of seven point check scales. The semantic differential was completed on evaluative, potency and activity dimensions using bipolar qualifiers derived from Osgood's scales for American-English. The semantic qualifiers were arranged on the 10 cm analogue scales so that exceptionally negative attitudes were represented by a score of zero, exceptionally positive attitudes by a score of 100 and neutrality of attitude by scores in the range 50 ± 7 (see tables 1,5). So as not to produce a "scoring set" the 10 cm analogue lines used to measure the "agreement" and "truthfulness'' of attitudinal statements were scored as 0 for "agreement" or "true" and 100 for "disagreement" or "false". (Tables 2,3 , 4, 6, 7.)
Three hundred respondents completed and returned the questionnaire. To validate the questionnaire and to obtain some idea of the reliability of the information offered, respondents were invited to identify their completed statements with a number/letter combination known only to themselves and then attend for personal interview using only this code as identification. Some l0 per cent of the respondents identified themselves in this way; the content of their interviews confirmed that the questionnaire was valid. in posing appropriate questions and that the subjects were internally consistent. Respondents were grouped as user or non-user according to their responses to the drug use inventories. Some individuals belonged to more than one group because of multidrug use, but they are not included in the following tables, when a comparison between users of different specific drugs is intended. The use of labels such as "chronic users" etc. is arbitrary and for convenience alone, labels are used according to the frequency of use of a particular drug, and are not intended to imply an evaluation over and above the operational definition given in table 5.
Levels of significance were calculated using Student's "t" test, the salient and statistically significant results at a p <.05 or better, are presented below. Since some individuals omitted items from the attitudinal scales a complete set of ratings is not available for all respondents. The figures in the following tables relate only to those subjects for whom complete data was available and so the numbers of respondents in any one group category may vary; e.g. there are 19 cannabis users in table 1 while, because two sets of data are incomplete, only 17 cannabis users feature in table 4. Since we are not establishing incidence or prevalence measures but looking at attitudinal parameters in groups of individuals defined by certain frequency of use patterns then it is deemed more appropriate to omit individuals with incomplete profiles rather than to "average" their results.
|
No. in group |
Mean deflection |
Standard deviation |
Level of significance |
|
|---|---|---|---|---|
|
Cannabis
|
||||
|
Non-users (never used)
|
149 | 36.8 | 17.9 | |
|
Users (using more than one per
|
p<0.00l
|
|||
|
month)
|
19 | 70.5 | 14.3 | |
|
Alcohol
|
||||
|
Non-users (never used or stopped
|
||||
|
using)
|
11 | 32.3 | 14.6 | |
|
Users (using more than II drinks
|
p<0.001
|
|||
|
per week)
|
51 | 73.0 | 12.5 | |
|
Tobacco
|
||||
|
Non-users (never smoked)
|
56 | 29.6 | 14.7 |
p<0.00l
|
|
Users (smokers)
|
85 | 51.4 | 16.0 |
Table 1 indicates that for each of the drugs in question i.e. alcohol, cannabis and tobacco, there exists a significant difference in the attitudinal ratings given by users and non-users of the specific drugs on the evaluative dimension of Osgood's semantic differential. However, no significant difference is to be found between tobacco users and alcohol users when compared on ratings of attitudinal statements: while, as tables 2 and 3 illustrate, significant differences exist between cannabis and alcohol users and cannabis and tobacco users compared on the same set of attitudinal statements. This would imply that alcohol and tobacco are, attitudinally that is, equivalent substances; while cannabis is held in a different semantic and attitudinal framework.
|
Statements |
Users of |
No. in group |
Mean deflection |
Standard deviation |
Level of significance |
|---|---|---|---|---|---|
|
I think a drug user is:
|
|||||
|
More emotionally unstable.
|
C
|
39 | 58.3 | 29.1 |
p<0.001
|
|
A
|
26 | 27.3 | 29.6 | ||
|
More interesting as a person.
|
C
|
39 | 63.9 | 25.8 |
p <0.001
|
|
A
|
26 | 84.5 | 17.8 | ||
|
Less able to cope with life
|
C
|
39 | 61.6 | 28.2 |
p<0.001
|
|
A
|
26 | 27.2 | 26.7 | ||
|
(Has) more friends
|
C
|
39 | 64.3 | 26.6 |
p<0.5
|
|
A
|
26 | 77.5 | 21.0 |
The alcohol users (A) in this sample had never used cannabis but consumed more than 11 drinks per week; the cannabis users (C) were those who had used cannabis more than 5 times.
Thus there is an attitudinal distinction to be made between cannabis users and those using either or both alcohol and tobacco. In tables 2 and 3 the lower mean deflection indicates more subjective agreement with the statement. The point of neutrality i.e. neither agreeing nor disagreeing with the statement would be represented by a score of 50.0 ± 7. Thus from table 2 we conclude that alcohol users regard drug users as "definitely emotionally unstable" and "definitely less able to cope with life".
Similar results occur in table 3. In both tables 2 and 3 the attitudes of the cannabis user towards drug users as "more interesting" and "more emotionally unstable" are about the point of neutrality, but extreme attitudes are held by the non-cannabis using group. Hindmarch (1972b.c.) has argued that attitudes can be used to explain the aetiology of cannabis use, and it is apparent from this present study (tables 2 and 3) that cannabis users hold positive attitudes towards drug users, in believing that they are "more able to cope with life", "more interesting" and "vested with more friends". These positive attitudes are necessary to support their behavioural involvement with the drug and furthermore, as Goode (1970) indicates, they will be contained within a sub-culture which is conducive to maintaining these positive attitudes. Martino and Truss (1973) have also shown the peer group belief in the safety and attractiveness of drug use to be strong among all levels of cannabis users.
|
Statements |
Users of |
No. in group |
Mean deflection |
Standard deviation |
Level of significance |
|---|---|---|---|---|---|
|
I think a drug user is:
|
|||||
|
More emotionally unstable .
|
C
|
39 | 58.3 | 29.1 |
p<0.001
|
|
T
|
12 | 26.4 | 27.0 | ||
|
More interesting as a person.
|
C
|
39 | 63.9 | 25.8 |
p < 0.05
|
|
T
|
12 | 82.4 | 26.9 | ||
|
More interested in sex
|
C
|
39 | 65.8 | 25.2 |
p<0.02
|
|
T
|
12 | 86.1 | 24.3 | ||
|
Less able to cope with life
|
C
|
39 | 61.6 | 28.2 |
p<0.001
|
|
T
|
12 | 26.1 | 24.7 | ||
|
More creative
|
C
|
39 | 59.9 | 29.0 |
p<0.02
|
|
T
|
12 | 81.1 | 23.3 |
Cannabis users (C) are those who have used cannabis more than 5 times, tobacco users (T) are respondents smoking more than 80 cigarettes per week (or equivalent in other tobacco) and have never used cannabis.
|
Statement |
No. |
Mean deflection |
Standard deviation |
Level of significance |
|
|---|---|---|---|---|---|
|
Drugs are alright if only taken occasionally
|
NCU
|
191 | 73.2 | 31.7 |
p<.001
|
|
CU
|
17 | 37.5 | 29.5 | ||
|
Drugs are an aid to creative people
|
NCU
|
191 | 80.7 | 24.9 |
p<.001
|
|
CU
|
17 | 50.8 | 28.3 | ||
|
Drugs are not so dangerous as newspapers make out
|
NCU
|
191 | 66.0 | 32.3 |
p<.001
|
|
CU
|
17'
|
13.7 | 14.0 | ||
|
Drugs can make you a fuller person
|
NCU
|
191 | 86.8 | 19.5 |
p<.001
|
|
CU
|
17 | 49.8 | 29.8 | ||
|
It is safer to drive with someone high on pot than someone drunk on alcohol
|
NCU
|
189 | 69.9 | 28.1 |
p<.001
|
|
CU
|
17 | 36.0 | 23.6 | ||
|
It would be fine to take drugs if it were not for the police
|
NCU
|
191 | 88.8 | 20.0 |
p<.001
|
|
CU
|
17 | 55.7 | 31.0 | ||
|
Drugs are a valuable new experience
|
NCU
|
191 | 79.5 | 26.8 |
p<.001
|
|
CU
|
17 | 33.4 | 24.6 | ||
|
Only fools get hooked on drugs
|
NCU
|
191 | 60.6 | 36.3 |
p<.02
|
|
CU
|
17 | 77.3 | 27.5 | ||
|
Pep pills are great for kicks
|
NCU
|
191 | 85.8 | 20.3 |
p<.02
|
|
CU
|
17 | 69.7 | 26.5 | ||
Cannabis users (CU) are taken to be respondents who use cannabis more than once monthly, while non-users (NCU) are those who have never used cannabis.
Since there are no significant differences between the responses of the alcohol and tobacco using groups when rated with respect to cannabis then it is meaningful to regard them together and to use the criterion of cannabis use alone in separating attitudinal statements. In other words respondents do not rank cannabis with alcohol and tobacco, as a social drug; rather cannabis is regarded as "a drug" while alcohol and tobacco are "not drugs". Table 4 compares non-cannabis users with cannabis users on a variety of attitudinal statements, the two groups being significantly different at a p < .02. The cannabis users hold all these statements to be "true" when compared with non-cannabis users (save "only fools get hooked on drugs"). Of importance is the extreme polarity of the user and non-user groups in the majority of these attitudinal situations. Specifically, non-cannabis users believe what they read in the newspapers concerning drugs; that cannabis produces a greater impairment of driving skills than alcohol and that "drugs do not aid creativity". These negative attitudes held by the non-cannabis users are independent of the level of legislation or likelihood of detection since they disagree most strongly with the statement "drug use is fine if it were not for the police". On this statement the drug users are effectively neutral. This result tends to devalue the notion of drug use as a deviant reaction against the establishment (Young, 1971) and attributes the negative feeling towards drug use to individual principles which work independently of societal norms and laws. Even cannabis users take no account of the possibility of police detection as a factor in determining their drug use and such findings, if confirmed on a larger scale, could well prove important to legislators believing law enforcement a possible deterrent to cannabis use.
TABLE 5
Level of cannabis use and associated attitudinal ratings of cannabis
|
Group |
Level of cannabis use |
No. in group |
Mean deflection |
Standard deviation |
Level of significance |
|---|---|---|---|---|---|
|
A
|
Non-users (never used cannabis)
|
149 | 36.8 | 17.9 |
p<0.001
|
|
B
|
Experimenters (used cannabis up to 5 times)
|
35 | 51.1 | 20.0 |
p<0.001
|
|
C
|
Casual users (use cannabis less than once per month)
|
14 | 69.6 | 12.1 |
N.S.
|
|
D
|
Users (use cannabis more than once per month
|
8 | 72.3 | 13.5 |
N.S.
|
|
E
|
Chronic users (use cannabis more than twice a week)
|
11 | 71.5 | 11.6 |
The mean deflection is the average score obtained on the evaluative dimensions of the semantic differential. See Osgood et al. (1957) and Hindmarch (1970).
Table 5 shows that as an individual progresses towards a more frequent, chronic use of cannabis so his attitude becomes more positive. This is in agreement both with the notion that an increased behavioural involvement would intensify the related attitudinal component; and with previous research (Martino and Truss, 1973) which has shown on a variety of measures, that attitudes to cannabis were positively related to actual cannabis use. Also of importance is the significant difference between non-users and experimenters and between experimenters and casual users (both at p <0.001). These differences tend to contradict theories of drug use escalation based simply on the development of pharmacological tolerance, since before an individual can move from an experimental stage to one of casual use he must overcome the attitudinal difference separating him from the higher use level. Several theories have been advanced (Hill, et al. 1960; Gilbert and Lombardi, 1967; Halstead and Neal, 1968; Rosenberg, 1969) attributing the development and escalation of drug use observed in some individuals to a prone or weak personality. However, as Mott (1972) has argued, individual personality characteristics are "irrelevant to the study of developing drug misuse because environmental factors are the major determinants of such behaviour".
By investigating an individual's attitudinal or belief system we are essentially taking into account the role of environmental factors as well as intrinsic variables such as personality, motivation and perception. Doob (1947) has argued that an attitude is an implicit correlate of an objective, i.e. overt, behaviour pattern. In turn, this implicit response can serve as a stimulus or drive for overt, observable behaviour. Campbell (1963) has also claimed that attitudes are internal manifestations of behavioural dispositions. Naturally, behaviour can be modified by experience; and so, therefore, can attitudes. Collins (1968) also illustrated the importance of the intimate relationship between attitudinal and behavioural systems.
We have shown earlier that a change in overt behaviour, in this instance frequency of cannabis use, was paralleled by a change in attitudinal valence. An attitudinal valence is regarded as a product of the individual personality but it also embraces the result of environment-organism interaction and other contingent environmental factors relating to past, present and even future behaviour.
The individual attitudinal framework is his internal cognizance of his external behavioural world. It is important for the integrity of his cognitive system, that personal attitudes and beliefs are not inconsistent or dissonant with overt behaviour. The notion that tension or stress is generated when behaviour and belief systems contradict each other or produce disharmony and conflict has been shown to be widely held within psychology (Aronson (1968)). It is hypothesized that certain individuals maintain their cognitive integrity by adopting an attitudinal framework which prohibits either an escalation of drug use, or in the case of non users, a commencement of drug use. These individuals could be regarded as internally consistent, in that they maintain their belief system by endogenous as opposed to exogenous factors. On the other hand there are individuals who tend to maintain cognitive consistency by altering their attitudinal framework to fit the change in their own behaviour in the external situation. They therefore place greater reliance on exogenous as opposed to endogenous factors. Such individuals having reached a particular level of cannabis use (in our tables, that of casual use) have to adjust their attitudinal system to take account of the change in overt behaviour, otherwise their attitudes would be dissonant with their behaviour. Once this cognitive conflict has been resolved, i.e. the attitudes restructured, then an increase in the frequency of cannabis use can be tolerated (even to a chronic level) without overt behaviour being inconsistent or dissonant with the new attitudinal framework. If, however, individuals cannot restructure their cognitive framework, then the only way they can maintain consistency and prevent conflict from arising is to reduce their overt behaviour (cannabis use) to an appropriate level in order to balance their internal beliefs with their drug using behaviour. Two distinct groups of individuals are represented in this present study. The first being internally consistent, do not allow dissonance i.e. conflict between beliefs and actual behaviour to occur; these are the non-users and experimenters. The second group of casual and more frequent users tend to reduce their dissonance by changing their attitudinal framework, and so we observe the increase in positive evaluation of cannabis as concomitant with the increase in reported frequency of cannabis use.
Of further interest is the polarised attitudinal separation of non-cannabis users from cannabis users of all levels. Previously Hindmarch (1970) found the attitudes of both users and non-users of cannabis to be positively biased; and since the present data was collected from a similar population a "hardening" of attitudes in the non using group is evident. Arguably this is for a variety of reasons; but, it is suggested that the vast amount of conflicting information regarding cannabis and its effects produced over the previous four years has been sufficient to produce conflict and dissonance in the attitudinal system of potential users. In order to reduce this dissonance and return their cognitive system to an integral harmonious state, individuals have relied on endogenous norms. In other words, cognitive consistency is maintained by regarding it as "dangerous", in general, to use a drug about which so much conflicting evidence is presented.
TABLE 6
Level of cannabis use and attitudinal statements
|
Level of use and mean score in cms for groups a |
|||||
|---|---|---|---|---|---|
|
Statement |
A |
B |
C |
D |
E |
|
I think a drug user is:
|
|||||
|
More emotionally unstable
|
24 | 37 | 60 | 63 | 56 |
|
More interesting as a person
|
83 | 73 | 63 | 72 | 60 |
|
Less successful in his academic work
|
42 | 49 | 56 | 61 | 45 |
|
More interested in sex
|
69 | 69 | 67 | 63 | 66 |
|
Less able to cope with life
|
24 | 41 | 57 | 65 | 74 |
|
Less ambitious
|
43 | 42 | 45 | 55 | 32 |
|
Has more friends
|
71 | 66 | 51 | 65 | 65 |
|
More creative
|
74 | 66 | 60 | 58 | 48 |
|
Really "with it"
|
85 | 85 | 81 | 79 | 70 |
|
a Groups:
|
A = Non-users
|
N =197
|
|
B = Experimenters
|
N =38
|
|
|
C = Casual users
|
N =15
|
|
|
D = Users
|
N =8
|
|
|
E = Chronic users
|
N =9
|
In summary
cannabis is not regarded like alcohol and tobacco as a social drug among members of a student population.
There are no attitudinal differences between users and non-users of alcohol and tobacco; while significant differences exist between users and non-users of cannabis.
The attitudinal separation of experimental users from more frequent users of cannabis is used to explain why individuals do not escalate from experimental to chronic cannabis use.
Since it is expected that persons need to be "consistent" in the attitudes they hold then we would expect fewer individuals constantly restructuring their framework to maintain parity with overt behaviour. So we expect fewer chronic and persistent cannabis users than experimenters and this was shown in this present sample and is also in accord with results of recent surveys in British University students (Smart and Whitehead, 1973).
The attitudinal separation of the non-cannabis user from the cannabis user is also an effective "barrier" to starting cannabis use. Even if a non-user takes cannabis once or twice, say at a party or other social gathering, then he is still unlikely to become a more frequent user because he holds a relatively negative set of attitudes towards cannabis compared with those using the drug more frequently.
TABLE 7
Level of cannabis use and attitudinal statements
|
Level of use and mean score in cms for groups a |
|||||
|---|---|---|---|---|---|
|
Statement |
A |
B |
C |
D |
E |
|
Drugs are all right if only taken occasionally
|
73 | 51 | 36 | 40 | 32 |
|
Drugs are an aid to creative people
|
81 | 73 | 59 | 58 | 42 |
|
Drugs are not as dangerous as newspapers make out
|
66 | 45 | 21 | 17 | 15 |
|
Drugs can make you a fuller person
|
87 | 71 | 64 | 47 | 47 |
|
It is safer to drive with someone high on pot than someone drunk on alcohol
|
70 | 64 | 50 | 38 | 27 |
|
Drugs are good because they make you self-confident
|
85 | 78 | 71 | 60 | 73 |
|
The risk of heroin hooking you is greatly over-exaggerated
|
84 | 74 | 84 | 76 | 64 |
|
It would be fine to take drugs if it were not for the police
|
89 | 80 | 64 | 65 | 46 |
|
Drugs are a valuable new experience
|
80 | 57 | 37 | 43 | 23 |
|
Only fools get hooked on drugs
|
61 | 58 | 68 | 80 | 73 |
|
Pep pills are great for kicks
|
86 | 80 | 68 | 73 | 68 |
|
Drugs are all right if one doesn't take alcohol at the same time
|
85 | 63 | 52 | 57 | 71 |
|
aGroups:
|
A = Non-users
|
N =191
|
|
B = Experimenters
|
N =38
|
|
|
C = Casual users
|
N =16
|
|
|
D = Users
|
N =6
|
|
|
E = Chronic users
|
N =11
|
Abelson R. P., E. Aronson, W. J. McGuire, T. M. Newcomb, M. J. Rosenberg and P. H. Tannenbaum. Theories of Cognitive Consistency: A Sourcebook. Chicago, Rand McNally, 1968.
Aronson, E. See Abelson et al. 1968.
Binnie H. L. The attitudes to drugs and drug takers of students at the University and Colleges of Education in an English Midland City. Vaughan Papers 14:1-29. Univ. of Leicester, 1969.
Blum R. H. Students and Drugs. Jossey Bass, San Francisco, 1969.
Bogg R. A., R. G. Smith and S. Russel. Drugs and Michigan high school students. Mimeograph, 1968.
Brooke-Crutchley, J. and J. Young. Student Culture. Enfield College of Technology. Mimeograph, 1971.
Campbell D. T. Social attitudes and other acquired behavioural dispositions in S. Koch. Ed. Psychology: A study of a science. Vol. 6. McGraw Hill: New York, 1963.
Collins B. E. See Abelson et al. 1968.
Doob L. The Behaviour of Attitudes. Psychol. Review 54: 135-156, 1947.
Einstein R., I. Hughes and I. Hindmarch. Patterns of use of alcohol, cannabis and tobacco in a student population. Brit. J. Addiction (submitted March, 1974).
Gilbert J. G. and D. N. Lombardi. Personality Characteristics of Young Male Narcotic Addicts . J. Consulting Psychol. 31: 536, 1967.
Goode E. Multiple Drug Use Among Marijuana Smokers. Social Problems 17: 48-64, 1969.
- - - - . The Marijuana Smokers. Basic Books: New York, 1970.
- - - - . Cigarette Smoking and Drug Use on a College Campus. Int. J. Addictions 7 (1): 133-140, 1972.
Halstead H. and C. D. Neal. Intelligence and Personality in Drug Addicts. Brit. J. Addiction 63: 237, 1968.
Hill H. E., C. G. Haertson and D. Glaser. Personality Characteristics of Narcotic Addicts as Measured by the MMPI. J. Gen. Psychol. 62, 1960.
Hindmarch I. Patterns of Drug Use in a Provincial University. Brit. J. Addiction 64: 395-402, 1970.
- - - - . Age Groups at Risk. Drugs and Society 1 (1): 19-24, 1971.
- - - - . Patterns of drug use and attitudes to drug users in a school aged population. In: Student Drug Surveys, pp. 77-95. New York, Einstein and Allen Baywood ed., 1972 (a).
- - - - . Patterns of drug abuse among school children. Bull. on Narcotics XXIV: 3, 23-26, 1972 (b).
- - - - . The patterns of drug use and the attitudes to drug users in school age and student populations. In: L'Homme et les substances psychoactives. ICAA, Amsterdam, vol. B4 1-10, 1972 (c).
Lavenhar M. A., E. A. Wolfson, A. Sheffet, S. Einstein and D. B. Louria. Survey of Drug Abuse in Six New Jersey High Schools: II - Characteristics of drug users and nonusers. In: Student Drug Surveys; New York, Einstein and Allen Baywood ed., 1972.
Martino E. R., and C. V. Truss. Drug Use and Attitudes Toward Social and Legal Aspects of Marijuana in a Large Metropolitan University. J. Counselling Psychol. 20 (2): 120-126, 1973.
McKay A. J., V. M. Hawthorne and McCartney. Drug taking among medical students at Glasgow University . Brit. Med. J. 1: 540-543, 1973.
Mott J. The Psychological Basis of Drug Dependence: The Intellectual and Personality Characteristics of Opiate Users. Brit. J. Addiction 67: 89-99, 1972.
Osgood C. E., G. J. Suci and P. H. Tannebaum. The Measurement of Meaning. Urbana, University of Illinois Press, 1957.
Rosenberg C. M. Young Drug Addicts: background and personality. J. Nerv. Mental Disease 148: 65, 1969.
Smart R. G. Relationships between parental and adolescent drug use. 1970. Mimeograph.
- - - - . and D. Fejer. Drug Use Among Adolescents and their Parents. J. Abnormal Psychol. 79: 153-160, 1972.
- - - - . and P.C. Whitehead. The prevention of drug abuse by lowering per capita consumption: distributions of consumption in samples of Canadian adults and British university students. Bull. on Narcotics XXV: 4, 49-55, 1973.
Weitman M., R. Scheble, K. G. Johnson and H. Abbey. Survey of Adolescent Drug Use. Correlations Among Use of Drugs. Amer. J. of Public Health 62: 166-170, 1972.
Young J. Drug Takers. London, MacGibbon and Kee, 1971.
