Journal of Youth and Adolescence, Vol. 13, No. 1, 1984
Prevalence and Patterns of Substance Use Among Early Adolescents Susan Keyes 1'3 and Jack Block 2'3
Received March 19, 1984
Prevalence and patterns o f substance use are described f o r a sample o f 105 San Francisco East Bay adolescents (age 14). Data are compared with national statistics on substance use among high school seniors. While alcohol use appeared comparable to the national statistics, tobacco use was less prevalent among this younger western sample. Despite the differences in ages, use o f marijuana, cocaine, and hallucinogens was similar to national high school prevalence; use o f other "harder" drugs was more extensive among the older, national sample. Contrary to typical findings, males and females were not found to differ in frequency or extent o f substance use; females appeared somewhat more involved in substance use at this early age. Initiation o f substance use occurred at early grade levels, suggesting that intervention efforts should begin prior to junior high, perhaps as early as fourth or fifth grade.
INTRODUCTION A s d r u g a n d a l c o h o l a b u s e h a v e b e c o m e i n c r e a s i n g l y serious a n d visible p r o b l e m s , r e s e a r c h e f f o r t s t o h e l p u n d e r s t a n d t h e e t i o l o g y o f s u b s t a n c e
This study was supported by National Institute of Mental Health Grant MH 16080 to Jack Block and Jeanne H. Block. IDepartment of Psychology, University of California, Berkeley. Received her Ph.D. from Harvard University. Main interest is cognitive development and development in adolescence. 2Department of Psychology, University of California, Berkeley. Received his Ph.D. from Stanford University. Main interest is personality development. ~Correspondence should be sent to Susan Keyes or Jack Block, Department of Psychology, University of California, Berkeley 94720. 1 0047-2891/84/0200-0001503.50/0 © 1984 Plenum Publishing Corporation
2
Keyes and Block
use have proliferated. While much early research focused on addicts or individuals in treatment, these studies necessarily were limited in generality, focusing as they did on the most extreme groups of substance users (Kandel, 1978). In recent years, our understanding of the prevalence and nature of substance use has been greatly enhanced by data obtained from national panel studies employing representative, nonclinical samples (Abelson et al., 1977; Johnston et al., 1979, 1981a, 1981b). These general population surveys confirm that, while the "popularity" of various licit and illicit substances may change from year to year, the prevalence of substance use is extensive, particularly among adolescents and youth. In a 1981 survey of over 17,000 high school seniors from 128 high schools around the United States, 60% reported using marijuana at least once, 16% reported use of hallucinogens, and 17% reported use of cocaine (Johnston et al., 1981a, 1981b). Information on grade in which use was initiated also was available for approximately 7000 pupils. These data revealed that by eighth grade 16% of the sample had already used marijuana, and by ninth grade 3 4 % - figures hp slightly from a similar 1979 survey (Johnston et al., 1979). Small percentages of pupils had also begun using other "harder" drugs (e.g., inhalants, hallucinogens, cocaine) prior to high school entry, suggesting that small but significant numbers of pupils have their first experience with illicit substances at quite early ages (also see Abelson et al., 1977; Kandel, 1980). Revealing as epidemiological and panel studies are in terms of documenting prevalence and patterns of substance use, the size of such studies limits the number of questions which they can address. Understanding how substance use relates to a broad class of developmental and environmental factors is difficult when sample sizes are large and assessments limited to surveys and written questionnaires; though Jessor and Jessor (1977, 1978), Johnston et al., (1979, 1981a, 1981b), Kandel et al., (1976, I978), and Brook et al. (1977, 1978, 1980) must be commended for both the scope and excellence of their data on substance use and its psychosocial correlates. An ongoing longitudinal study of ego and cognitive development, conducted with a sample of (now) adolescents from East Bay communities of San Francisco, provides a unique opportunity to explore substance use and its relationship to a wide range of developmental and environmental factors. Though the sample is not large in comparison with national panel studies and epidemiological surveys (N = 105), a wealth of data is available for each individual participating in the study and covers a large span of years. Assessments of all participants were made as early as age 3 and at frequent intervals thereafter. At age 14, as part of a larger assessment battery, information was obtained on substance use.
Substance Use Among Early Adolescents
In this report, we describe the prevalence and patterns of substance use in this longitudinal sample and compare these data with national statistics. A 1981 survey of high school seniors is taken as the national comparison sample in all cases (see Johnson et aL, 1981a, 1981b). A discrepancy in age exists between our longitudinal sample and the national sample. We felt, however, that the advantage of using statistics basically contemporary with our own assessments (made in 1981-1982) outweighed the disadvantage of the difference in ages. To our knowledge, no comparable recent national statistics are available on substance use among eighth- and ninth-grade students. In subsequent reports we will explore prospective relationships between personality attributes, home environment and later substance use (e.g., Block et aL, manuscript in preparation).
METHOD Subjects Subjects were 105 adolescents, 54 females and 51 males, participating in an ongoing study of ego and cognitive development conducted at the University of California, Berkeley. The exact number of subjects in any analysis, varies somewhat. About two-thirds of the subjects are White, onefourth are Black, and one-twelfth Asian. Subjects were initially recruited into the study at age 3, while attending either a university-run nursery school or a parent-cooperative nursery school, and were assessed on wide-ranging batteries of measures at ages 3, 4, 5, 7, 11, and 14. Subjects live primarily in urban settings and are heterogeneous with respect to social class and parents' education.
Procedures Included in the assessment battery at age 14 was an extensive individual interview, conducted by a skilled clinician and typically lasting 55-75 minutes (range 40 minutes to over two hours). All interviews are videotaped. The interview included such topics as schoolwork, family dynamics, peer relations, current activities, and future aspirations. Within the interview, subjects also were asked about their use of the following substances: wine and/or beer, liquor, tobacco, marijuana, and other "harder" drugs. In addition to their verbal responses, subjects were asked to indicate which substances they had used by checking off the appropriate items on a substance use checklist (see Table I).
4
Substance Tobacco
Keyes and Block
Table I. Substances Included on the Substance Use Checklist Example
Beer
Wine Hard liquor Marijuana Hashish Hallucinogens Inhalants Barbiturates Tranquilizers Amphetamines Cocaine Codeine-type medicines Heroin Other
Whisky, gin LSD, peyote, mescaline Glue, gasoline, nitrous oxide, amyl nitrate Seconal, Quaaludes Valium, Librium Dexedrin, Methedrine
While self-report data on substance use are always subject to underreporting, a number o f investigators indicate that these data have a high concordance with more objective measures (Jessor and Jessor, 1977; Perry et al., 1980; Single et al., 1975). Subjects in this study appeared to answer our questions about substance use with candor. The interviewer was skilled in gaining rapport, in eliciting information without inducing discomfort, and in recognizing when a subject wished to close a topic. Thus, while the data obtained vary in specificity from subject to subject, the data are likely to reflect honest responses to our queries or to reflect somewhat the underreporting phenomenon. S u b s t a n c e U s e Measures
Data from the substance use portion of the interview were independently scored by two raters. Agreement on coding was high; in the few cases o f discrepancy, items were discussed to reach consensus. For each of the substances listed in Table I, information was coded for (1) how frequently the substance was used, (2) with whom the substance was typically used, and (3) school grade in which use was initiated. Descriptions o f "how you feel" when taking each substance also were recorded. RESULTS Alcohol-Tobacco Distributions were calculated on usage frequency for beer a n d / o r wine, liquor, tobacco, marijuana, and "harder" drugs. For beer/wine,
Substance Use Among Early Adolescents
liquor, and tobacco, subjects were divided into five groups; (0) never used substance; (1) used once or twice or (for alcohol only) used with any frequency but only in a family context; (2) used sometimes, occasionally; and (3) used frequently. A final group was composed of those who had used a substance but did not indicate frequency of use. Distributions by usage classification for these three substance groups are displayed in Table II. Note that nearly all the subjects had at least sampled beer and/or wine, though nearly half had only done so once or twice or used them only in a family setting (e.g., on holidays, special occasions). Nearly one-fourth of the sample indicated occasional use of beer/wine, but only 5% drank frequently. An additional 22°70 noted use of beer/wine, but gave no indication of frequency. Data for liquor use are quite similar, but indicated less extensive use. More subjects had never tried liquor (33%), only 19% had tried it only once or twice or with their families, and fewer subjects indicated occasional use. Again, a sizeable number of subjects (3207o) noted use, but did not indicate frequency. Tobacco use was the least frequent, with only 10070of the sample using tobacco occasionally or frequently; nearly half of the sample had never tried tobacco; 21% indicated use, but gave no information on frequency. When these analyses were performed for the sexes separately, no differences were observed at conventional levels of significance. Two nonsignificant but noticeable differences in distribution were detected, however. Females were slightly more likely than males to have never tried tobacco (30 females vs. 19 males), and confessed~frequont-alcohol users were often female. For liquor, all 5 frequent users were female as were 4 out of 5 of the frequent users of beer/wine. Given the large numbers of subjects for whom frequency-of-use data are not available, these observations must remain tentative. Prevalence of alcohol use was comparable to prevalence among Johnson et al.'s sample (1981a, 1981b) of high school seniors. These national statistics indicated that 93% of all students had used alcohol at least once, compared with 96070 of the present sample. Recall, however, that Table El. Frequency of Substance Use: Beer/Wine, Liquor, Tobacco (Percent)
Never used Used once or twice or used only with family Used sometimes Used frequently Used: no indication of frequency
Beer/wine (N = 105)
Liquor (N = 103)
Tobacco (N = 103)
4
33
48
47 23 5 22
19 12 4 32
21 6 4 21
6
Keyes and Block
nearly half o f the present sample had used some form o f alcohol only once or twice, or only with their families. Though similar data on context o f use are unavailable for the national survey, frequent and unsupervised use o f alcohol appeared to be more prevalent among the high school seniors. For tobacco, prevalence o f use was much lower for this sample than for the national group. Seventy-one percent o f all high school seniors reported some use of tobacco, but only 52% o f the present sample had tried tobacco at least once. Only 4 % o f the present sample smoked regularly, as opposed to 16% o f the national sample. When comparison is made with only high school seniors from the West, ,t.hese figures are less discrepant. Only 10% o f high school seniors from the West smoked regularly. Marijuana
Subjects were divided into six groups o f marijuana users: (0) never used marijuana; (I) used once or twice; (2) used sometimes, occasionally; (3) used once a month; (4) used once a week; and (5) used more than once a week. Only one subject noted usage, but gave no indication o f frequency o f use. This individual was classified in group 2: used sometimes, occasionally. Examination o f all other items from this subject's protocol indicated that this procedure was somewhat likely to underrepresent, not overrepresent, her usage o f marijuana. Distributions for the marijuana usage groups are given in Table III. Nearly half o f the sample had never tried marijuana, and 13% had used it only once or twice. A further 20% reported occasional use, and 18% reported more frequent use (i.e., once a month or more), with 10% o f these reporting use o f more than once a week. Distributions also were calculated for the sexes separately and revealed no significant differences, although 11 of the 19 more frequent users o f marijuana were female (i.e., 20°70 o f all females vs. 16% o f all males). Marijuana use was somewhat less prevalent in the present sample, compared to national statistics, with 51% reporting use at least once, as opposed to 60% o f all high school seniors. Ten percent o f the present sample Table HI. Frequency of Marijuana Use (Percent)
Never used Used once or twice Used sometimes Used once a month Used once per week Used more than once,per week
Marijuana (N = ~o5) 49 13 20 3 5 10
Substance Use Among Early Adolescents
used marijuana frequently (i.e., more than once a week), compared with 21°70 of the national sample. These data may reflect a lower prevalence of use, or they may simply result from the discrepancy in age between the two groups. One would expect that over the next several years the incidence of marijuana use will increase among our longitudinal sample to match, or exceed, the 1981 norms.
Drug Usage Data on the use of "harder" drugs were tallied, and frequencies are displayed in Table IV. These data show that the majority of subjects had never sampled these substances. Hashish, cocaine, and hallucinogens (most often LSD) were the drugs more frequently used recreationally, and used by 12070-19°70 of the sample. Data on these harder substances also were analyzed in terms of number of drugs used, and these data are displayed in Table V. Again, the large majority of subjects have never used any of these substances, and 14% have tried only one (most frequently hashish or cocaine). While the sexes did not differ significantly in usage of harder drugs, once again a difference in usage was detectable. Of those who had used two or more of the harder substances, 11 were female and 5 male. Of those who had tried hallucinogens or cocaine, females also outnumbered males (hallucinogens, 9 females vs. 3 males; cocaine, 13 females vs. 6 males). Comparisons with national statistics suggest that use of harder substances was generally less prevalent (by an average of about 1007o) among the present sample, with only two exceptions. Use of hallucinogens was relatively comparable between this sample and the national group (12°70 vs. 16o70, respectively), as was use of cocaine (18o70 vs. 17o/0). Cocaine use among this sample, however, was well below the 26°/o prevalence reported Table IV. Frequency o f Substance Use: Harder Drugs (Percent) a
Hashish LSD/hallucinogens Inhalants (e.g., glue, solvents) Barbiturates Tranquilizers Amphetamines Cocaine Codeine Heroin Other ~ N r a n g e s from 101 t o 103.
Never used
Used at least once
81 88 97 93 91 93 82 81 99 99
19 12 2 5 4 7 18 3 1 1
Prescribed 1 2 5 -16 --
Keyes and Block Table V. Number of Harder Drugs Used (Percent) Number o f drugs used
Users (N = 103)
0 1 2 3 4 5 6 7 8 9
70 14 5 5 3 2
I
regionally for high school seniors from the West. Heroin use was extremely rare in both samples (107o).
Relationships Among Usage Measures Analyses were performed to compare frequency of use across all substances, and to determine whether heavier users o f one type or group o f substances would also be heavy users of other substances (as suggested by Gove et al., 1979; Jessor and Jessor, 1977). For these analyses individuals for whom frequency-of-use information was not available were classified in intermediate categories, although when these analyses were performed for only individuals with frequency data available, the results were identical. For harder drugs there was a strong relationship among substances used. Individuals who had used one or more harder drugs were more likely to use marijuana sometimes or frequently (Fisher's exact text, p < 0.001). Of the 31 individuals who had used one or more harder drugs, moreover, 15 used marijuana frequently (i.e., once a month or more) and all but 1 of the most frequent marijuana users (more than once a week) had used at least one of the harder drugs. Individuals who had used one or more o f the harder drugs were also more likely to sometimes or frequently drink beer/wine (Fisher's exact test, p < 0.001) and liquor (Fisher's exact text, p < 0.001), but did not differ from nondrug users in use o f tobacco. For marijuana users, similar relationships were found. Individuals who used marijuana sometimes or frequently were also more likely to sometimes or frequently drink beer/wine (Fisher's exact test, p < 0.001) and liquor (Fisher's exact test, p < 0.001). Once again there was no relationship with tobacco use. With one exception, substance use was not related to socioeconomic status or e t h n i c i t y - a result similar to those reported by Brook et al. (1983)
SubstanceUse AmongEarlyAdolescents
and Kandel (1980). Beer/wine use was related to socioeconomic status (r = 0.27, p < 0.02), with individuals from more affluent families more likely to drink wine and beer. There were no significant relationships for liquor, tobacco, marijuana, or drug use, however, and for all substances the distributions of usage by ethnicity closely matched the ethnic distribution of the sample as a whole. Context of Usage
All substances were typically reported to be used with friends, but in a few cases individuals reported using substances with siblings or other family members (e.g., cousins). One male subject reported using marijuana and another reported using cocaine with their families (parent included). These data mesh with findings from other studies which suggest that parent and peer models for substance use increase the likelihood of initiating use (Brook et al., 1980; Jessor and Jessor, 1977; Kandel, 1980). Subjects also were asked their reasons for using drugs. The most common reason was "for fun," and the next most common reasons were "to see what they are like," "to be sociable," and "to relax." Very few mentioned philosophical reasons (e.g., to gain new insights). One male admitted that part of his reason for using drugs was self-destuctive and one female said she used drugs because they were fun, but also to get at her parents. Initiation of Usage
Information was obtained on when subjects first began using substances and these data are summarized in Table VI. Sixth, seventh, and eighth grades appear to be the years which most commonly marked initiation into substance use, with marijuana use more likely to begin in sixth and seventh grades, and harder drug use more likely to begin in seventh and eighth grades. For alcohol use, data are less complete, although eighth grade appears to mark an upturn in usage. As previously noted, very few subjects were occasional or frequent users of tobacco, and it is difficult to assess what grade, if any, marks an upturn in tobacco usage. Seventh and eighth grades appeared to be particularly salient periods for females in terms of substance uptake. While the initiation of substance use by males was quite evenly distributed across all grades, this was not the case for females. Of the 15 pupils initiating marijuana use in seventh grade, 12 were female. For beer/wine use in ninth grade, 10 of the 14 pupils initiating social use were female. More of the users of harder drugs in seventh and eighth grades were also female.
8
E**
Prevalence and Patterns of Substance Use Among Early Adolescents Susan Keyes 1'3 and Jack Block 2'3
Received March 19, 1984
Prevalence and patterns o f substance use are described f o r a sample o f 105 San Francisco East Bay adolescents (age 14). Data are compared with national statistics on substance use among high school seniors. While alcohol use appeared comparable to the national statistics, tobacco use was less prevalent among this younger western sample. Despite the differences in ages, use o f marijuana, cocaine, and hallucinogens was similar to national high school prevalence; use o f other "harder" drugs was more extensive among the older, national sample. Contrary to typical findings, males and females were not found to differ in frequency or extent o f substance use; females appeared somewhat more involved in substance use at this early age. Initiation o f substance use occurred at early grade levels, suggesting that intervention efforts should begin prior to junior high, perhaps as early as fourth or fifth grade.
INTRODUCTION A s d r u g a n d a l c o h o l a b u s e h a v e b e c o m e i n c r e a s i n g l y serious a n d visible p r o b l e m s , r e s e a r c h e f f o r t s t o h e l p u n d e r s t a n d t h e e t i o l o g y o f s u b s t a n c e
This study was supported by National Institute of Mental Health Grant MH 16080 to Jack Block and Jeanne H. Block. IDepartment of Psychology, University of California, Berkeley. Received her Ph.D. from Harvard University. Main interest is cognitive development and development in adolescence. 2Department of Psychology, University of California, Berkeley. Received his Ph.D. from Stanford University. Main interest is personality development. ~Correspondence should be sent to Susan Keyes or Jack Block, Department of Psychology, University of California, Berkeley 94720. 1 0047-2891/84/0200-0001503.50/0 © 1984 Plenum Publishing Corporation
2
Keyes and Block
use have proliferated. While much early research focused on addicts or individuals in treatment, these studies necessarily were limited in generality, focusing as they did on the most extreme groups of substance users (Kandel, 1978). In recent years, our understanding of the prevalence and nature of substance use has been greatly enhanced by data obtained from national panel studies employing representative, nonclinical samples (Abelson et al., 1977; Johnston et al., 1979, 1981a, 1981b). These general population surveys confirm that, while the "popularity" of various licit and illicit substances may change from year to year, the prevalence of substance use is extensive, particularly among adolescents and youth. In a 1981 survey of over 17,000 high school seniors from 128 high schools around the United States, 60% reported using marijuana at least once, 16% reported use of hallucinogens, and 17% reported use of cocaine (Johnston et al., 1981a, 1981b). Information on grade in which use was initiated also was available for approximately 7000 pupils. These data revealed that by eighth grade 16% of the sample had already used marijuana, and by ninth grade 3 4 % - figures hp slightly from a similar 1979 survey (Johnston et al., 1979). Small percentages of pupils had also begun using other "harder" drugs (e.g., inhalants, hallucinogens, cocaine) prior to high school entry, suggesting that small but significant numbers of pupils have their first experience with illicit substances at quite early ages (also see Abelson et al., 1977; Kandel, 1980). Revealing as epidemiological and panel studies are in terms of documenting prevalence and patterns of substance use, the size of such studies limits the number of questions which they can address. Understanding how substance use relates to a broad class of developmental and environmental factors is difficult when sample sizes are large and assessments limited to surveys and written questionnaires; though Jessor and Jessor (1977, 1978), Johnston et al., (1979, 1981a, 1981b), Kandel et al., (1976, I978), and Brook et al. (1977, 1978, 1980) must be commended for both the scope and excellence of their data on substance use and its psychosocial correlates. An ongoing longitudinal study of ego and cognitive development, conducted with a sample of (now) adolescents from East Bay communities of San Francisco, provides a unique opportunity to explore substance use and its relationship to a wide range of developmental and environmental factors. Though the sample is not large in comparison with national panel studies and epidemiological surveys (N = 105), a wealth of data is available for each individual participating in the study and covers a large span of years. Assessments of all participants were made as early as age 3 and at frequent intervals thereafter. At age 14, as part of a larger assessment battery, information was obtained on substance use.
Substance Use Among Early Adolescents
In this report, we describe the prevalence and patterns of substance use in this longitudinal sample and compare these data with national statistics. A 1981 survey of high school seniors is taken as the national comparison sample in all cases (see Johnson et aL, 1981a, 1981b). A discrepancy in age exists between our longitudinal sample and the national sample. We felt, however, that the advantage of using statistics basically contemporary with our own assessments (made in 1981-1982) outweighed the disadvantage of the difference in ages. To our knowledge, no comparable recent national statistics are available on substance use among eighth- and ninth-grade students. In subsequent reports we will explore prospective relationships between personality attributes, home environment and later substance use (e.g., Block et aL, manuscript in preparation).
METHOD Subjects Subjects were 105 adolescents, 54 females and 51 males, participating in an ongoing study of ego and cognitive development conducted at the University of California, Berkeley. The exact number of subjects in any analysis, varies somewhat. About two-thirds of the subjects are White, onefourth are Black, and one-twelfth Asian. Subjects were initially recruited into the study at age 3, while attending either a university-run nursery school or a parent-cooperative nursery school, and were assessed on wide-ranging batteries of measures at ages 3, 4, 5, 7, 11, and 14. Subjects live primarily in urban settings and are heterogeneous with respect to social class and parents' education.
Procedures Included in the assessment battery at age 14 was an extensive individual interview, conducted by a skilled clinician and typically lasting 55-75 minutes (range 40 minutes to over two hours). All interviews are videotaped. The interview included such topics as schoolwork, family dynamics, peer relations, current activities, and future aspirations. Within the interview, subjects also were asked about their use of the following substances: wine and/or beer, liquor, tobacco, marijuana, and other "harder" drugs. In addition to their verbal responses, subjects were asked to indicate which substances they had used by checking off the appropriate items on a substance use checklist (see Table I).
4
Substance Tobacco
Keyes and Block
Table I. Substances Included on the Substance Use Checklist Example
Beer
Wine Hard liquor Marijuana Hashish Hallucinogens Inhalants Barbiturates Tranquilizers Amphetamines Cocaine Codeine-type medicines Heroin Other
Whisky, gin LSD, peyote, mescaline Glue, gasoline, nitrous oxide, amyl nitrate Seconal, Quaaludes Valium, Librium Dexedrin, Methedrine
While self-report data on substance use are always subject to underreporting, a number o f investigators indicate that these data have a high concordance with more objective measures (Jessor and Jessor, 1977; Perry et al., 1980; Single et al., 1975). Subjects in this study appeared to answer our questions about substance use with candor. The interviewer was skilled in gaining rapport, in eliciting information without inducing discomfort, and in recognizing when a subject wished to close a topic. Thus, while the data obtained vary in specificity from subject to subject, the data are likely to reflect honest responses to our queries or to reflect somewhat the underreporting phenomenon. S u b s t a n c e U s e Measures
Data from the substance use portion of the interview were independently scored by two raters. Agreement on coding was high; in the few cases o f discrepancy, items were discussed to reach consensus. For each of the substances listed in Table I, information was coded for (1) how frequently the substance was used, (2) with whom the substance was typically used, and (3) school grade in which use was initiated. Descriptions o f "how you feel" when taking each substance also were recorded. RESULTS Alcohol-Tobacco Distributions were calculated on usage frequency for beer a n d / o r wine, liquor, tobacco, marijuana, and "harder" drugs. For beer/wine,
Substance Use Among Early Adolescents
liquor, and tobacco, subjects were divided into five groups; (0) never used substance; (1) used once or twice or (for alcohol only) used with any frequency but only in a family context; (2) used sometimes, occasionally; and (3) used frequently. A final group was composed of those who had used a substance but did not indicate frequency of use. Distributions by usage classification for these three substance groups are displayed in Table II. Note that nearly all the subjects had at least sampled beer and/or wine, though nearly half had only done so once or twice or used them only in a family setting (e.g., on holidays, special occasions). Nearly one-fourth of the sample indicated occasional use of beer/wine, but only 5% drank frequently. An additional 22°70 noted use of beer/wine, but gave no indication of frequency. Data for liquor use are quite similar, but indicated less extensive use. More subjects had never tried liquor (33%), only 19% had tried it only once or twice or with their families, and fewer subjects indicated occasional use. Again, a sizeable number of subjects (3207o) noted use, but did not indicate frequency. Tobacco use was the least frequent, with only 10070of the sample using tobacco occasionally or frequently; nearly half of the sample had never tried tobacco; 21% indicated use, but gave no information on frequency. When these analyses were performed for the sexes separately, no differences were observed at conventional levels of significance. Two nonsignificant but noticeable differences in distribution were detected, however. Females were slightly more likely than males to have never tried tobacco (30 females vs. 19 males), and confessed~frequont-alcohol users were often female. For liquor, all 5 frequent users were female as were 4 out of 5 of the frequent users of beer/wine. Given the large numbers of subjects for whom frequency-of-use data are not available, these observations must remain tentative. Prevalence of alcohol use was comparable to prevalence among Johnson et al.'s sample (1981a, 1981b) of high school seniors. These national statistics indicated that 93% of all students had used alcohol at least once, compared with 96070 of the present sample. Recall, however, that Table El. Frequency of Substance Use: Beer/Wine, Liquor, Tobacco (Percent)
Never used Used once or twice or used only with family Used sometimes Used frequently Used: no indication of frequency
Beer/wine (N = 105)
Liquor (N = 103)
Tobacco (N = 103)
4
33
48
47 23 5 22
19 12 4 32
21 6 4 21
6
Keyes and Block
nearly half o f the present sample had used some form o f alcohol only once or twice, or only with their families. Though similar data on context o f use are unavailable for the national survey, frequent and unsupervised use o f alcohol appeared to be more prevalent among the high school seniors. For tobacco, prevalence o f use was much lower for this sample than for the national group. Seventy-one percent o f all high school seniors reported some use of tobacco, but only 52% o f the present sample had tried tobacco at least once. Only 4 % o f the present sample smoked regularly, as opposed to 16% o f the national sample. When comparison is made with only high school seniors from the West, ,t.hese figures are less discrepant. Only 10% o f high school seniors from the West smoked regularly. Marijuana
Subjects were divided into six groups o f marijuana users: (0) never used marijuana; (I) used once or twice; (2) used sometimes, occasionally; (3) used once a month; (4) used once a week; and (5) used more than once a week. Only one subject noted usage, but gave no indication o f frequency o f use. This individual was classified in group 2: used sometimes, occasionally. Examination o f all other items from this subject's protocol indicated that this procedure was somewhat likely to underrepresent, not overrepresent, her usage o f marijuana. Distributions for the marijuana usage groups are given in Table III. Nearly half o f the sample had never tried marijuana, and 13% had used it only once or twice. A further 20% reported occasional use, and 18% reported more frequent use (i.e., once a month or more), with 10% o f these reporting use o f more than once a week. Distributions also were calculated for the sexes separately and revealed no significant differences, although 11 of the 19 more frequent users o f marijuana were female (i.e., 20°70 o f all females vs. 16% o f all males). Marijuana use was somewhat less prevalent in the present sample, compared to national statistics, with 51% reporting use at least once, as opposed to 60% o f all high school seniors. Ten percent o f the present sample Table HI. Frequency of Marijuana Use (Percent)
Never used Used once or twice Used sometimes Used once a month Used once per week Used more than once,per week
Marijuana (N = ~o5) 49 13 20 3 5 10
Substance Use Among Early Adolescents
used marijuana frequently (i.e., more than once a week), compared with 21°70 of the national sample. These data may reflect a lower prevalence of use, or they may simply result from the discrepancy in age between the two groups. One would expect that over the next several years the incidence of marijuana use will increase among our longitudinal sample to match, or exceed, the 1981 norms.
Drug Usage Data on the use of "harder" drugs were tallied, and frequencies are displayed in Table IV. These data show that the majority of subjects had never sampled these substances. Hashish, cocaine, and hallucinogens (most often LSD) were the drugs more frequently used recreationally, and used by 12070-19°70 of the sample. Data on these harder substances also were analyzed in terms of number of drugs used, and these data are displayed in Table V. Again, the large majority of subjects have never used any of these substances, and 14% have tried only one (most frequently hashish or cocaine). While the sexes did not differ significantly in usage of harder drugs, once again a difference in usage was detectable. Of those who had used two or more of the harder substances, 11 were female and 5 male. Of those who had tried hallucinogens or cocaine, females also outnumbered males (hallucinogens, 9 females vs. 3 males; cocaine, 13 females vs. 6 males). Comparisons with national statistics suggest that use of harder substances was generally less prevalent (by an average of about 1007o) among the present sample, with only two exceptions. Use of hallucinogens was relatively comparable between this sample and the national group (12°70 vs. 16o70, respectively), as was use of cocaine (18o70 vs. 17o/0). Cocaine use among this sample, however, was well below the 26°/o prevalence reported Table IV. Frequency o f Substance Use: Harder Drugs (Percent) a
Hashish LSD/hallucinogens Inhalants (e.g., glue, solvents) Barbiturates Tranquilizers Amphetamines Cocaine Codeine Heroin Other ~ N r a n g e s from 101 t o 103.
Never used
Used at least once
81 88 97 93 91 93 82 81 99 99
19 12 2 5 4 7 18 3 1 1
Prescribed 1 2 5 -16 --
Keyes and Block Table V. Number of Harder Drugs Used (Percent) Number o f drugs used
Users (N = 103)
0 1 2 3 4 5 6 7 8 9
70 14 5 5 3 2
I
regionally for high school seniors from the West. Heroin use was extremely rare in both samples (107o).
Relationships Among Usage Measures Analyses were performed to compare frequency of use across all substances, and to determine whether heavier users o f one type or group o f substances would also be heavy users of other substances (as suggested by Gove et al., 1979; Jessor and Jessor, 1977). For these analyses individuals for whom frequency-of-use information was not available were classified in intermediate categories, although when these analyses were performed for only individuals with frequency data available, the results were identical. For harder drugs there was a strong relationship among substances used. Individuals who had used one or more harder drugs were more likely to use marijuana sometimes or frequently (Fisher's exact text, p < 0.001). Of the 31 individuals who had used one or more harder drugs, moreover, 15 used marijuana frequently (i.e., once a month or more) and all but 1 of the most frequent marijuana users (more than once a week) had used at least one of the harder drugs. Individuals who had used one or more o f the harder drugs were also more likely to sometimes or frequently drink beer/wine (Fisher's exact test, p < 0.001) and liquor (Fisher's exact text, p < 0.001), but did not differ from nondrug users in use o f tobacco. For marijuana users, similar relationships were found. Individuals who used marijuana sometimes or frequently were also more likely to sometimes or frequently drink beer/wine (Fisher's exact test, p < 0.001) and liquor (Fisher's exact test, p < 0.001). Once again there was no relationship with tobacco use. With one exception, substance use was not related to socioeconomic status or e t h n i c i t y - a result similar to those reported by Brook et al. (1983)
SubstanceUse AmongEarlyAdolescents
and Kandel (1980). Beer/wine use was related to socioeconomic status (r = 0.27, p < 0.02), with individuals from more affluent families more likely to drink wine and beer. There were no significant relationships for liquor, tobacco, marijuana, or drug use, however, and for all substances the distributions of usage by ethnicity closely matched the ethnic distribution of the sample as a whole. Context of Usage
All substances were typically reported to be used with friends, but in a few cases individuals reported using substances with siblings or other family members (e.g., cousins). One male subject reported using marijuana and another reported using cocaine with their families (parent included). These data mesh with findings from other studies which suggest that parent and peer models for substance use increase the likelihood of initiating use (Brook et al., 1980; Jessor and Jessor, 1977; Kandel, 1980). Subjects also were asked their reasons for using drugs. The most common reason was "for fun," and the next most common reasons were "to see what they are like," "to be sociable," and "to relax." Very few mentioned philosophical reasons (e.g., to gain new insights). One male admitted that part of his reason for using drugs was self-destuctive and one female said she used drugs because they were fun, but also to get at her parents. Initiation of Usage
Information was obtained on when subjects first began using substances and these data are summarized in Table VI. Sixth, seventh, and eighth grades appear to be the years which most commonly marked initiation into substance use, with marijuana use more likely to begin in sixth and seventh grades, and harder drug use more likely to begin in seventh and eighth grades. For alcohol use, data are less complete, although eighth grade appears to mark an upturn in usage. As previously noted, very few subjects were occasional or frequent users of tobacco, and it is difficult to assess what grade, if any, marks an upturn in tobacco usage. Seventh and eighth grades appeared to be particularly salient periods for females in terms of substance uptake. While the initiation of substance use by males was quite evenly distributed across all grades, this was not the case for females. Of the 15 pupils initiating marijuana use in seventh grade, 12 were female. For beer/wine use in ninth grade, 10 of the 14 pupils initiating social use were female. More of the users of harder drugs in seventh and eighth grades were also female.
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