Patterns of drug use among young adults

Addictive Behaviors, Vol. 14, pp. 99-104, 1989 Printed in the USA. All rights reserved.

0306-4603/89 $3.00 + .OO Copyright 0 1989 Pergamon Press plc

BRIEF REPORT

PATTERNS OF DRUG USE AMONG YOUNG ADULTS

ALBERT MEHRABIAN and TINE STRAUBINGER University of California, Los Angeles

Abstract - The present study assessed patterns of multiple drug use among a sample of university employees and students who had been identified as having moderately high drug use habits. Use of eleven categories of legal and illegal drugs was tested and subjects reported how much of each drug they currently and habitually used. Factor analysis yielded three factors of drug use. Four of the items in the first factor (hallucinogens, cocaine, marijuana, alcohol) exhibited moderately strong and positive intercorrelations, suggesting that this particular pattern of drug use was the most common and/or reliable among young adult drug users. Sedatives and opiates were the highest loading items on the second factor, suggesting a pattern of drug use motivated by the desire for relaxation and stress avoidance. The third factor identified a pattern of legal stimulant use involving two of the three food-like categories of items employed in the present study (i.e., caffeinated cola beverages and chocolate, but not coffee). The results provided only mixed support for the hypothesis that categories of drugs with similar pharmacological properties define patterns of multiple drug use.

Many studies of drug use simply reported percent-of-population users of various drugs, usually for adolescents, without reporting intercorrelations among categories of drug use (e.g., Adler & Lotecka, 1973; Johnson, Donnelly, Scheble, Wine, & Weitman, 1971; Mizner, Barter, & Werme, 1970). Other investigators, however, identified generalized tendencies toward drug use for a diversity of populations. Sadava (1984) reviewed evidence to show that there is an individual difference di- mension of tendency to use psychoactive drugs. Evidence reviewed and provided by Whitehead (1974) also led to the conclusion that “users of most drugs are more likely to use almost any other drug than are nonusers” (p. 203). Single, Kandel, and Faust (1974) tested a very large sample of high-school students and found that uses of various categories of drugs (hard liquor, marijuana, hashish, LSD, other psychedelics, methedrine, other amphetamines, barbiturates, tranquilizers, cocaine, heroin, other opiates, and inhalants) were positively and significantly intercorrelated. In particular, correlations were greatest among drugs that were either legal (or illegal) and among drugs which had similar pharmacological properties. Guttman (1950) scaling results showed that drug use among adolescents tended to be cumulative, that is, individuals who had used drugs which ranked high on the Guttman scale also had used drugs ranking lower on that scale. The authors noted that in contrast to sugges- tions by some investigators, drug use began with legal drugs (alcohol and tobacco) rather than with marijuana.

In a study similar to that of Single et al. (1974), Gould, Berberian, Kasl, Thompson, and Kleber (1977) provided additional evidence for the interrelatedness of use of various categories of drugs. Once again, the subjects were high-school

Reprint requests should be sent to Albert Mehrabian, Department of Psychology, UCLA, 405 Hilgard Avenue, Los Angeles, CA 90024.

99

100 ALBERT MEHRABIAN and TINE STRAUBINGER

students. Their study is particularly relevant here in that they obtained “ever used” and “current use” data from their subjects. As with most other studies reviewed, their first analysis involved reports of subjects ever using a particular drug or combi- nation of drugs. Their second analysis, in contrast, involved reports of current uses of various drugs. Association patterns for both the “ever used” and “current use” data indicated that various categories of drug use were strongly and positively asso- ciated. Alcohol use, incidentally, was as strongly related to the use of “harder” drugs as was marijuana use. Gould et al. (1977) also used scalogram analysis which suggested a progressive relationship in the use of the following categories of drugs: alcohol, marijuana, hashish, barbiturates, amphetamines, LSD, mescaline, cocaine, and heroin.

Thus, Guttman (1950) scaling has been useful for rank ordering within-individual drug use in terms of a progression. Once an individual is identified as a user of a high-ranked drug, the probabilities are great that he or she has also used, or currently uses, the lower-ranked drugs. Guttman scaling, then, has some bearing on the ways in which drug use habits develop within the same individual. Understandably, then, Guttman scaling has been used mostly with adolescent subjects whose drug use behaviors were still in flux. In contrast, the present study focused on an older sample of subjects with the objective of identifying current or ongoing patterns of multiple drug use rather than longitudinal within-individual progressions in drug use. A key difference, then, between the present method and methods of other studies reviewed was that the latter dealt with whether an individual had ever used a particular drug - answered with a simple “yes” versus “no.” Here, the question was what drugs subjects used currently and how much of each they used habitually. Therefore, factor analysis, rather than scalogram analysis, was used to identify the patterns of legal and illegal drug use among selected subjects who were moderately heavy drug users. In line with findings already noted, it was hypothesized that categories of drugs with similar pharmacological properties (e.g., stimulates or sedatives) are likely to form the factors or patterns of drug use.

METHOD

Subjects Preliminary and confidential interviews were conducted with potential subjects to

identify those with moderately high habitual drug-use habits. Approximately 90% of those who were asked to continue to participate in the study volunteered to do so. These were 61 employees and students (30 men and 31 women) at the University of California with a mean age of 24 years (SD = 7 years).

Materials A questionnaire measure of drug use (Mehrabian, 1986) was employed. The ques-

tionnaire included 30 items which tested for the use of ten categories of drugs. Sets of three items each assessed weekly consumption of caffeine from each of the following sources (e.g., caffeinated cola beverages, tea, coffee, chocolate) and assessed weekly consumption of nicotine from tobacco, amphetamines, cocaine, hallucinogens, marijuana, sedatives (e.g., barbiturates, tranquilizers, or nonbarbiturate sedatives), opiates (morphine, codeine, heroin), and methadon.

A measure of habitual level of alcohol use (Mehrabian & Russell, 1978) also was used. The latter measure included 12 items which assessed weekly consumption of beer, wine, and liquor, rate at which alcohol was consumed typically, and incidence

Drug use patterns 101

of drunkenness. Items of the measure constituted a single factor and therefore a homogeneous scale. A weighted sum of selected items (Mehrabian & Russell, 1978, equation 2) provided a single overall score for total habitual level of alcohol consumption.

Procedure Subjects who agreed to participate in the study were given the two sets of question-

naires. They were informed that all information they disclosed would be treated in a strictly confidential manner and that it would not be necessary for them to record their names on the response sheets. Subjects completed the drug-use questionnaire first and then responded to the alcohol-use measure. They recorded their sex and age on one of the response sheets. Testing duration was approximately ten minutes per subject.

RESULTS AND DISCUSSION

Internal check of responses to the drug-use questionnaire The drug-use questionnaire contained sets of three interrelated questions for each

category of drug (e.g., sedatives) to assess accuracy of reports. The three questions for the category of marijuana were: (a) How many days a week do you smoke marijuana? (b) On the days you do smoke marijuana, how many joints or the equivalent do you typically have? (c) In total, how many joints or the equivalent of marijuana do you have in a week? Thus, if a subject responded with 7 to question (a), 25 to question (b), and approximately 175 (e.g., 160 to 190) to question (c), the responses were considered to have been accurate.

The preceding checking procedure was used and showed that subjects indeed had answered the questionnaire carefully and that all the data could be used in subse- quent analyses. It should be noted that the sets of three numbers provided by subjects for each drug indicated that, generally, subjects were not simply multiplying figures (a) and (b) to obtain the total weekly consumption, figure (c). Rather, subjects seemed to be estimating an approximate overall weekly consumption figure for each drug by using the guidelines given in the questionnaire.

Drug use levels in the sample Subjects reported their drug use levels in terms of units or measures familiar to

them (e.g., cups of coffee, number of amphetamine tablets, or lines of cocaine). The following weekly averages are based on these raw data provided by subjects. How- ever, dose equivalences are also noted and are based on data given by the Staff, Department of Justice Training Center (1979).

Total weekly caffeine consumption reported by subjects, assessed from their consumption of coffee, tea, and chocolate, averaged the equivalent of 16.8 cups of coffee per week (SD = 13). Total weekly nicotine intake averaged the equivalent of 9 cigarettes per week (SD = 33). Average weekly amphetamine consumption was .4 tablets (SD = 1.7), with each tablet approximating 10 mg. Average weekly cocaine consumption was 1.5 lines (SD = 3. l), with each line approximating 40 mg. Average weekly hallucinogen intake consisted of .2 units (SD = .5), with each unit approximately 5 mg. The alcohol use mean was .7 SD higher than norms (based on un- selected subjects, including non-drinkers), given by Mehrabian and Russell (1978), thus indicating a moderate level of alcohol use in the present sample. Average marijuana consumption per week was 3.4 joints (SD = 5.6). Average weekly use of


sedatives was . 1 units (SD = .57), with approximately 75 mg per unit. Weekly opiate use was .07 doses (So = .36), with approximately .06 grams per dose.

Based on the latter statistics, the present subjects were viewed as having moderately high habitual drug-use habits.

Total weekly consumption figures for each of the ten categories of drugs obtained from the drug-use questionnaire plus the single score of overall level of habitual alcohol use (Mehrabian & Russell, 1978, equation 2) constituted the 11 items employed in the factor analysis.

The 11 x 11 matrix of intercorrelations among drug- and alcohol-use scores was factor analyzed and a principal components solution was obtained. There were three factors with eigenvalues exceeding unity which accounted for 4% of the total variance (24%, I%, and 1 l%, respectively). The low percentage of total variance accounted for by the first factor suggested that drug and alcohol use did not constitute a single, homogeneous scale and that factor analysis was justified for the present sample of subjects. Oblique rotation of the factors yielded the following groupings.

Factor 1: hallucinogens (.75), cocaine (.72), marijuana (.68), alcohol (.63), tobacco (.19), amphetamines (.18)

Factor 2: sedatives (.58), opiates (.41), coffee (.38) Factor 3: caffeinated cola beverages (.69), chocolate (.40)

Factor loading scores are provided in parentheses following each item or category of drug use and, within each factor, items are listed in descending magnitudes of factor loadings. All factor intercorrelations were low and insignificant. Factor 1 correlated - . 11 (df = 59, p > . 10) with Factor 2 and correlated - .02 with Factor 3. Factor 2 correlated - .08 with Factor 3.

The strongest pattern of interrelatedness was evidenced by the first four items listed under Factor 1 (hallucinogens, cocaine, marijuana, alcohol). Intercorrelations among these four items were all positive and significant (& = 59, p < .002), ranging from .36 to .62 and averaging .48. The latter intercorrelations suggested that, among the drug categories tested, the probability of combined use of any subset of the four drugs (hallucinogens, cocaine, marijuana, alcohol) was the greatest and that this particular pattern of drug use was the most reliable for moderately heavy drug users in the young adult population.

The preceding pattern also corroborated findings by Gould et al. (1977) and Single et al. (1974), as well as the extensive review of findings of Kaufman (1982), in showing that alcohol was an important part of a general pattern of legal and illegal drug use.

Comparable correlations were offered by Single, Kandel, and Faust (1974, Table 1) for their adolescent sample of subjects from New York public secondary schools. For their sample also, LSD, cocaine and marijuana use exhibited moderately high intercorrelations. However, alcohol (hard liquor) use was not a strong correlate of the other three drug-use categories (correlating .19 with LSD use, .12 with cocaine use, and .37 with marijuana use).

The highest loading items in Factor 2 were sedatives and opiates. Insofar as opiates, as well as sedatives, have the effect of lowering arousal (e.g., Sadava, 1975, p. 27), the constellation suggested a pattern of drug use motivated by the desire for relaxation and stress avoidance. Since coffee (the item with the smallest loading on this factor) is a stimulant, it detracts somewhat from this interpretation.

Drug use patterns 103

Factor 3 identified a pattern of legal stimulant use involving two of the three food-like categories of items employed in the present study (i.e., caffeinated cola beverages and chocolate, but not coffee). Thus, drugs with a similar pharmacological property which involved a significant caloric intake were distinguished as a separate group with the present factor.

The factorial patterns require discussion in the context of the proposed hypothesis. All six items in Factor 1, with possible exceptions of marijuana and alcohol, have arousal increasing properties. In the case of alcohol, review of the evidence suggested that low blood-alcohol levels increase arousal, whereas high blood-alcohol levels reduce it (Russell & Mehrabian, 1975). Mehrabian (1976, chap. 4) provided a rationale as to how infrequent use and/or low doses of alcohol and marijuana increase arousal whereas frequent use and/or large doses of these two drugs have the paradoxical effect of lowering arousal. If, in accordance with the latter analysis, moderate alcohol and marijuana doses have stimulant effects (and the present sample of subjects reported moderate levels of use for these two drugs), then Factors 1 and 3 support the hypothesis in showing that habitual multiple stimulant use is one very strong pattern of drug use (Factor 1) as well as a weaker pattern involving legal stimulants (Factor 3). Evidence from Factor 2 was mixed in that only the two highest loading items (sedatives and opiates) lower arousal and the third (coffee) increases arousal. In sum, the patterns of drug use identified here only provided mixed support for the proposed hypothesis.

The present results and interpretations need to be treated tentatively because of the relatively small sample size and because the hypothesis was not supported clearly by factor analytic results. Also, the present findings are most aptly generalized to samples of young adults in moderately affluent urban areas where a variety of drugs are readily available and affordable. In short, the scope of the present study is limited both in terms of characteristics of the sample and the sample size. Additional studies employing larger and more diverse samples are needed to provide more comprehensive tests of the hypothesis.

REFERENCES

Adler, P.T., & Lotecka, L. (1973). Drug use among high school students: Patterns and correlates. The International Journal of the Addictions, 8, 537-548.

Gould, L.C., Berberian, R.M., Kasl, S.V. Thompson, W.D., & Kleber, H.D. (1977). Sequential patterns of multiple-drug use among high school students. Archives of General Psychiatry, 34, 216222.

Guttman, L. (1950). The basis for scalogram analysis. In Stouffer et al. (Eds.), Measurement and predic- tion (pp.‘60-90). New York: Wile; _

Johnson, K.G., Donnelly, J.H., Scheble, R., Wine, R.L., & Weitman, M. (1971). Survey of adolescent drug use I - Sex and grade distribution. American Journal of Public Health, 61, 24112432.

Kaufman, E. (1982). The relationship of alcoholism and alcohol abuse to the abuse of other drugs. American Journal of Drug and Alcohol Abuse, 9, 1-17.

Mehrabian, A. (1976). Public places and private spaces: the psychology of work, play, and living en- vironments. New York: Basic Books.

Mehrabian, A. (1986). Arousal-reducing effects of chronic stimulant use. Motivation and Emotion, 10, l-10.

Mehrabian, A., & Russell, J.A. (1978). A questionnaire measure of habitual alcohol use. Psychological Reports, 43, W-806.

Mizner, G.L., Barter, J.T., & Werme, P.H. (1970). Patterns of drug use among college students: A preliminary report. American Journal of Psychiatry, 127, 15-24.

Russell, J.A., & Mehrabian, A. (1975). The mediating role of emotions in alcohol use. Journal of Studies on Alcohol, 36, 1508-1536.

Sadava, S.W. (1975). Research approaches in illicit drug use: a critical review. Genetic Psychology Monographs, 91, 3-59.


Sadava, S.W. (1984). Concurrent multiple drug use: Review and implications. Journal of Drug Issues, 22, 623-636.

Single, E., Kandel, D., & Faust, R. (1974). Patterns of multiple drug use in high school. Journal ofHealth and Social Behavior, 15, 344-357.

Staff, Department of Justice Training Center. (1979). Narcotics manual. Sacramento, CA: Law Enforce- ment Training Center.

Whitehead, P.C. (1974). Multidrug use: Supplementary perspectives. The fnternational Journal of the Addictions, 9, 18s204.

Documents

Patterns of drug use among young adults