Young Adult Drug Use and Delinquency: Childhood Antecedents and Adolescent Mediators

Young Adult Drug Use and Delinquency: Childhood Antecedents and Adolescent Mediators JUDITH S. BROOK, Eo.D., MARTIN WHITEMAN, PH.D., STEPHEN J. FINCH, PH.D., AND PATRICIA COHEN, PH.D.

ABSTRACT Objective: The aims of this study were (1) to examine the childhood, early adolescent, and late adolescent predictors of young adult drug use and delinquency; and (2) to explore the effects of drug use on delinquent behavior. Method: Data were gathered during the course of a 20-year longitudinal study of children representative of the Northeast. Data were gathered on childhood aggression, early and late adolescent drug use and delinquency, and young adult drug use and delinquency. Results: Overall, the results were consistent with our proposed model. Childhood aggression had an adverse effect on young adult drug use and female deviant behavior. Drug use and delinquency during early and late adolescence served as the mediator between childhood aggression and young adult drug use. Moreover, adolescent drug use was associated with later delinquency. Conclusions: The findings indicated that childhood aggression was related to both young adult drug use and delinquency. Second, there was stability of drug use and delinquency between early adolescence and young adulthood. Third, drug use during early adolescence had an impact on delinquency not only in early adolescence, but also in late adolescence and young adulthood. J. Am. Acad. Child Ado/esc.

Psychiatry, 1996, 35(12):1584-1592. Key Words: drug use, adolescence, delinquency, aggression, young adult.

During recent years, increased attention has been devoted to the relation between childhood aggression and adult drug use and delinquency. There is evidence to suggest that early childhood aggression increases the risk of drug use and adult delinquency (Dobkin et al., 1995; Hawkins et al., 1992; McCord, 1988; Schedler and Block, 1990). In a classic study, Block et al. (1988) reported that childhood personality characteristics of less emotional control predicted increased adolescent drug use. Kellam et al. (1983), in a landmark study of lower-class African-Arnerican youngsters living in Chicago, found that aggressive first graders were at increased risk for drug use during adolescence.

Accepted May 5, 1996. Drs. Brook and Whiteman are with the Mount Sinai School ofMedicine, New York; Dr. Finch is with the State University of New York at Stony Brook; and Dr. Cohen is with Columbia University, New York. The investigation was supported in part by Research Grant DA03188 and Research Scientist Award DA00118 to Dr. Brook from the National Institute on Drug Abuse. The suggestions of Coryl Jones are greatly appreciated. The manuscript was prepared by Linda Capobianco. Reprint requests to Dr. Brook, Mt. Sinai School ofMedicine, Box 1044A, 1 Gustave L. Levy Place, New York, NY 10029. 0890-8567/96/3512-1584$03.00/0©1996 by the American Academy of Child and Adolescent Psychiatry.

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The present research has a number of unique features. First, our focus is long-range, extending from childhood to young adulthood. Second, the study uses a prospective cohort design. Thus, reports of aggressive behavior in early childhood were obtained prior to reports of drug use and delinquency, which were obtained in early and late adolescence and young adulthood. Use of the prospective method protects against the difficulty of interpreting cross-sectional relations by enabling one to time-order the risk factors in relation to the dependent variable. Third, the study is based on a large community sample. In comparison to those studies that use clinical or small samples, we are in a better position to make inferences to the general population. Finally, having obtained data on drug use and delinquency during early and late adolescence, we are able to examine some potential adolescent mediating mechanisms by which childhood aggression may be related to increased drug use in young adulthood. Two mediators that may be operative are adolescent drug use and adolescent delinquency, both contributors to young adult drug use and delinquency. Nevertheless, supportive data for mediating mechanisms have been lacking because there are few longitudinal studies that

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include the requisite links between childhood aggression, the potential adolescent mediators, and young adult drug use. In this research we not only examine two major mediating factors (early and late adolescent drug use and delinquency), but also a hypothesized sequence of these mediating factors. It has been repeatedly demonstrated that drug use and delinquency during adolescence and young adulthood are associated (see review by White, 1990). Research on drug use and crime suggests that heavy drug use and drug abuse are associated with criminal behaviors (Anglin and Speckart, 1988; Clayton and T uchfeld, 1982). Related to this, alcohol abuse has been associated with crime and violence (Collins, 1988; Crawford et al., 1982; Fagan, 1989). Alcohol and drug abuse have also been found to be related to social deviance (Smith and Newman, 1990). Hammersley et al. (1989) reported that polydrug use was linked to theft. One hypothesis to explain the association of drugs and delinquency is that there is a common cause. Some researchers have maintained the two behaviors share a common biological, psychological, or social factor (e.g., Collins, 1988; Massey and Krohn, 1986). For example, Robins and Wish (1977) suggested that these two behaviors may be part of a clinical condition that existed prior to the onset of drug use or delinquency (Robins, 1966, 1978). Childhood aggression may represent an aspect of such a syndrome. In an earlier study based on this data set, we reported that since the relation of adolescent drug use and delinquency was maintained despite control on childhood aggression, aggression could not be considered a crucial common cause (Brook et al., 1992). A second hypothesis of this study is that drug use has an impact on later crime and on delinquency. Substance use has psychopharmacological effects which may have direct effects on delinquency. Drug use may also make the person less concerned with the consequences of his or her behavior such as becoming involved in crime. Finally, drug use may lead to crime in order to support the drug behavior. A third hypothesis is that deviance increases the probability of later drug use. There are data to support this interpretation (Hawkins et al., 1987; Kandel et al., 1986). One mechanism to support the linkage between early deviance and later drug use is the deviant adolescent's selection of drug-using peer groups.

The research has shown strong stability beginning in middle childhood, particularly for strong characteristics such as aggression (Eron and Huesmann, 1990; McCord, 1988; Olweus, 1980; Urban et al., 1991). Subject stability has also been shown for theft/vandalism (Wilson and Herrnstein, 1985). Considerable evidence has also been obtained with respect to the continuity of drug use (Brook and Cohen, 1992; Robins and Pryzbeck, 1985). While the literature cited above throws light on the relationship between childhood aggression and later drug use and delinquency, many questions are still unanswered. In a previous study, we examined the mediating mechanisms between childhood aggression and drug use and delinquency during late adolescence. Our findings indicated that childhood aggression was related to drug use in early adolescence, which in turn was related to drug use in late adolescence. Childhood aggression was also related to delinquency during late adolescence. The mediating links between childhood aggression and late adolescent delinquency were deviant behavior during early adolescence and drug use during late adolescence. The present study extends and builds on our previous research on childhood aggression and late adolescent deviant behavior. In this report, our focus is on the relation of childhood aggression and young adult deviant behavior. More specifically, we investigated the role of adolescent deviant behavior as a mediator of the relation of childhood aggression on early adult behavior. The developmental model that we tested is illustrated in Figure 1. We hypothesized that childhood aggression is associated with drug use during early adolescence, which in turn is associated with drug use during late adolescence. Drug use during late adolescence was thought to be related to drug use

IA;I-------'.~ Q~ ~ ~

8

/

1

DrugUse Time 3

1

~

__

DrugUse Tune 4

1

Fig. 1 Hypothesized model for interrelation of aggression, drug use, and delinquency. Circles represent latent constructs, and one-headed arrows represent paths of influence between variables.

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during young adulthood. We hypothesized that at each developmental period, drug use would have an impact on delinquency. Finally, with regard to the relation between childhood aggression and young adult delinquency, we hypothesized that childhood aggression would affect young adult delinquency via the stability of drug use or through continued delinquency during adolescence.

METHOD Sample A sample of families from two upstate counties in New York (Albany and Saratoga) were selected using a multistage, random design with complete enumeration. Eighty-five percent of the families agreed to participate in the research. At the time the sample was originally drawn, the families and the areas from which they came were representative of the northeastern United States with regard to income, education, and occupational status. One child from each family was randomly selected within the appropriate age range using Kish tables. (For a complete description of the sampling procedure, see Kogan et al., 1977.) The mother of the selected child was then interviewed (time 1, or T I ) . At T I , the children (N = 500) were between the ages of 5 and 10 years. At time 2 (T,), 8 years later, the participating families were reassessed with an expanded protocol. At T" the children's ages ranged from 13 to 18 years. A second follow-up evaluation (T 3 ) was conducted 2V2 years later, when the subjects were from 16 to 21 years of age. Onehalf of the sample was male. At T 3, 63% of the families were intact, and 76% came from urban areas. The ethnic distribution of the sample was as follows: white, 92%; African-American, 3%; and other, 5%. At T 3, the median income was $31,000; mean years of schooling for mothers and fathers were 12.6 and 12.8, respectively. A third follow-up evaluation, T 4, was conducted several years later, when the subjects were from 22 to 27 years of age. Approximately 80% of the sample was included in the follow-up study. Approximately one half of the sample was male. The ethnic distribution of the sample was as follows: white, 91%; AfricanAmerican, 4%; and other minority group members, 5%. The median income was $37,500; mean years of schooling for mothers and fathers were each 12.7. The families that were lost to followup at T 4 were younger, were more urban, more dependent on welfare, had lower maternal education, and had more single parents. The number of dropouts (20%) compared with the subjects retained in the study appears in several reports (Cohen and Brook, 1987; Cohen et al., 1989). In this article, we report on those subjects (163 males and 195 females) for whom we have complete data at all points in time.

Procedure At Tl> trained interviewers interviewed the mothers in their own homes. A structured, face-to-face interview, consisting of questions about the child's personality, behavior, and development, as well as about child-rearing techniques, family structure, family health, and demographic factors, was administered. At T" T 3, and T 4,

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both the mother and child were simultaneously, but separately, interviewed in their home by trained interviewers. The adolescents and young adults were given self-administered questionnaires consisting of a number of closed-ended items assessing their own personality, behavior, mental health, and drug use. The subjects were paid for their participation in the study.

Measures At T I , five manifest measures were used to assess the latent variable, aggression. The measures included the following: anger, aggression toward siblings, noncompliance, nonconforming behavior (Cohen and Velez, 1983, unpublished manuscript), and temper (Kogan et al., 1977). At T 2, T 3, and T 4, the latent variable of drug use was hypothesized to be measured by items that assessed the frequency of use of hard liquor, marijuana, and other illicit drugs. The other illicit drugs category included cocaine, heroin, amphetamines, barbiturates without a prescription, lysergic acid diethylamide (LSD), and methaqualone (Quaaludes). The T" T 3, and T 4 measures of alcohol use consisted of 5-point scales ranging from "none" (1) to "more than three drinks a day" (5); measures for marijuana use at T 2, T 3, and T 4 had a 7-point rating scale, ranging from "none" (1) to "daily use" (7); and measures for other illicit drug use at T" T 3, and T 4 had scales that ranged from "never" (1) to "daily use" (7). At T" T 3, and T 4, a delinquency latent variable consisted of items that tapped the frequency of truancy, cheating on tests, fighting, general theft, and school locker theft.

RESULTS

Latent variable strucrural equation models were used to examine the empirical credibility of the proposed theoretical processes (noted in Fig. 1). Maximum likelihood estimates of the model coefficients were obtained by using LISREL VII (Joreskog and Sorbom, 1988). In accord with our previous research and the findings of Stacy and Newcomb (1995), we focused on the effect ofdrug use on delinquency. Nevertheless, caution is required in interpreting these models because of the assumption that drug use causes contemporary delinquency. The means and standard deviations of the Tl> T z, and T 3 variables were obtained earlier and appear in a previous report (Brook et al., 1992). The T 4 means and standard deviations are presented in Table 1. The males reported greater delinquent behavior than the females at T z, T 3, and T 4• The standard deviations of some of the manifest variables were significantly larger for males than for females. With increased age, more of the delinquency measures showed gender differences. Using LISREL VII structural equation programs (Joreskog and Sorbom, 1988), we analyzed several variants of the model presented in Figures 2 and 3 to minimize the possibility that we overlooked

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Fig. 2 Male LISREL model showing standardized coefficients. Circles represent latent constructs, and one-headedarrows represent paths of influence between variables. SES = socioeconomic status. *p ~ .05; *~p ~ .01; ***p ~ .001.

a model that had a better fit to the data. We analyzed males and females separately as was done in our previous report. The LISREL VII estimates of the A coefficients at T 4 appear in Table 1. (The A coefficients obtained on data collected at earlier times appear in a previous report [Brook et al., 1992J.) The modification indices suggested that the assignment of manifest variables to latent variables was correct. For males, the largest modification index for the assignment of a manifest variable to a latent variable was 6.7, for assigning illicit drug use at T 3 to childhood aggression. For females, the largest modification index was 10.3, for assigning truancy at T 2 to delinquency at T 3. The estimated parameters for the males were essentially equal to those for the females. The LISREL analysis indicates that the male and female models differed significantly; more specifically, some of the male and female structural coefficients differed. We tested the null hypothesis that the structural coefficients for the male and female data were equal. A LISREL analysis (with 55 of the parameters

Fig. 3 Female LISREL model showing standardized coefficients. Circles represent latent constructs, and one-headedarrows tepresent paths of influence between variables. SES = socioeconomic status. *p s .05; **p ~ .01; ***p ~ .001.

equal) that fit the combined male and female model reported above, with a number of the structural coefficients set equal for males and females, had a X2 statistic for this model that was 1,356.02 on 868 df The loss in X2 value associated with setting the 55 parameters equal is not significant. Figures 2 and 3 reveal that the major structural differences between the male and female models were with respect to associations between drug use, age, and socioeconomic status (SES). For the males, the direct pathways from age to drug use at T 3 and T 4 were significant and negative, but these coefficients were not significant for the females. However, the total effect, which is the sum of the direct paths plus the effect of the indirect paths, was significant at T 3 and not related at T 4 for either sex. SES was significantly and positively related to drug use at T 3 and T 4 for the females but was not related for the males. Males

Figure 2 presents the standardized solution for the males. The standardized coefficient of a direct path is given above the path. The only direct path with a tstatis~ic with absolute value less than 2 was from age to childhood aggression. The model had a X2 statistic of 603.68 on 405 df and a goodness-of-fit index of 0.82. Although the X2 statistic was significant, the structural part of the model had extremely strong evaluative statistics. For example, the largest modification index for a structural parameter was 2.14 (p > .10) (SES to delinquency at T 3 ) . This nonsignificant finding suggests that the model is adequate for the structural components. The largest modification index for the parameters describing the correlation of the residual errors of the manifest variables was 9.03, indicating a correlation of residual variance between childhood noncompliance and major illegal drugs at T 4• Since this occurred with only one of the 405 additional possibilities, it may be attributed to chance based on Bonferroni's inequality. With regard to the demographic factors, there was a strong negative direct path from the parent's measured SES to childhood aggression (t = -2.81). There was also an extremely strong positive direct path from age to drug use at T 2 (t = 5.82) and strong negative direct paths from age to drug use at T 3 (t = -3.04) and from age to drug use at T 4 (t = -2.24).

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TABLE 1 Measurement Model Statistics at T , by Sex Females Squared Multiple Correl ation

Latent and Manifest Variable

Tru ancy" Cheating Fighting Theft Locker theft Hard liquor" Marijuana Other illicit drugs a

Squared Multiple Correlation

1.00

.29

1.00

.38

0.92 0.35

.49

1.16

.54

.24

0.62

.38

0.62 1.06

0.48

.26 .24 .50

.27 .5 1 .36

1.00 7.54

.20

.48

4.11

.49

1.00 5.21 3.09

0.81

.53

These variables have the value of the A coefficient fixed at 1 so that the standard deviation is O.

There was a statistically significant direct effect of childhood aggression on drug use and delinquency at T z (t = 2.16). Both drug use and delinquency showed continuities in behavior. Thus, there was strong continuity in the pattern of drug use from T , to T 3 (t = 5.80) and from T 3 to T 4 (r = 4.04) . Similarly, there was strong continuity in the pattern of delinquency at T z to T 3 (t = 3.19) and from T 3 to T 4 (t = 3.84). With regard to the cross-sectional paths between drug use and delinquency, there were positive paths between drug use and delinquency at T z, at T 3 , and at T 4 (T z, t = 5044 ; T 3, t = 3.77; T 4, t = 3.90) c. With regard to the longitudinal paths between drug use and delinquency, there were significant negative direct paths from drug use at T z to delinquency at T 3 (t = -3.16) and from drug use at T 3 to delinquency at T 4 (t = -3.20). Although these direct paths had negative coefficients, the total effects (as will be subsequently noted) of earlier drug use on later delinquency (T 3 ) were significantly positive. Likewise, the total effect of drug use at T 3 on delinquency at T 4 was also significantly positive. Females

Figure 3 presents the standardized solution for the females with the associated t values. The model had a Xz statistic of 682.3 4 on 408 df and a goodness-offit index of 0.82. Although the Xz statistic was significant, the structu ral part of the model had extremely strong evaluative statistics. For example, the largest modification index for a structural parameter was 4.20 (delinquency at T z and delinquency at T 4 ) . Age was significantly related to drug use at T z• SES was related to drug use at both T 3 and T 4• With regard to the

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Males

measurement model, it was noted above that the male and female models were similar. There was a significantly positive direct path from childhood aggression to drug use at T z (t = 2.66). There was strong cont inu ity of behavior of both drug use and delinquency. The t values of the coefficient s of direct paths from drug use at T z to drug use at T 3 and from drug use at T 3 to T 4 were 7.22 and 4.60, respectively. The t values of the coefficients of the direct path s from delinqu ency at T z to delinquency at T 3 and from delinquency at T 3 to delinquency at T 4 were 3.19 and 3.86, respectively. As in the male model, the coefficient of the direct path from drug use at T , to delinquency at T 3 was negative and statistically significant (t = 3041) . Nevertheless, the total effect between T z and subsequent delinquency is positive, as will be presented later. Furthermore, contrary to the male findings, a path between drug use at T 3 and delinquency at T 4 was not significant. Total Effects

M ale Results. An examination of the total effects of each endogenous variable estimated in the analysis helps in the interpretation of the coefficients. Table 2 gives the total effects of the variables in the model that were not exogenous. The t values of the total effects of childhood aggression on drug use and delinquency at T z and delinquency at T 3 were both greater than 2. There was a trend toward significant total effects between childhood aggression and T 4 drug use and delinquency. As measured by total effects, childhood aggression had a significant continuing effect on both a boy's subsequent delinquency and use of drugs at T 3, and there was a trend

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TABLE 2 T otal Effects on Subsequent Latent Variables for Males Latent Variable

Aggression T I

Dru g Use T 2

Drug use at T 2

0.19* (2.17) 0.33* (2. 10) 0.20* (2. 13) 0.27* (2.00) 0.08t (1.93) 0.11 (1.61)

1.70** (5.44) 1.02** (5.8 1) 1.38** (4.17) 0.43** (3.77)** 0.58* (2.24)

Delinquency at T 2 Drug use at T 3 Delinqu ency at T 3 Drug use at T 4 Delinquency at T 4

D elinqu ency T 2

0.00 - a 0.95** (3.18) 0.00

-

a

0.61** (2.63)

Drug Use 'r,

2.33** (3.77) 0.42** (4.05) 1.20** (2.92)

Delinquency T,

Dru g Use T,

0.00

-

a

0.64** (3.84)

2.34* * (3.90)

Note: Entries in parentheses are the t values of the total effects reported. The total effect of a delinquency variable on the subsequent drug variable is zero by virtue of the specification of the model in Figure 1. t p < .10; * P < .05; ** P < .0 1.

a

for child aggression and drug use and delinquency at T 4• Significant total effects were obtained between drug use at T 2 and subsequent drug use at T 3 and T 4 (t values were nearly 4) . Significant relations were also obtained between drug use at T 2 and delinquency at T 2, T 3, and T 4• Similarly, the t values of the total effects of drug use at T 3 on delinquency at T 3 and T 4 were significant. The t values of the total effect of earlier delinquency on subsequent delinquency were greater than 2.5 in all cases. Female Results. Table 3 gives the total effects for the females in the same format as Table 2 gives for the males. As shown in the model , childhood aggression

is statistically related to drug use and delinquency at T 2 and T 3 (all t values greater than 2.0). Childhood aggression was also significantl y related to both drug use and delinquency at T 4• There were no significant differences between males and females in the direct effects of aggression on deviance . The stability relation between earlier and later drug use and delinquency was tested as equalf in males and females, except for the association of T 3 drug use and T 4 drug use. Similarly, male patterns of relationships between drug use and delinquency parallel those of the females. The total effect of dru g use at T 2 and T 3 on each subsequent variable in the model was positive and

TABLE 3 T otal Effects on Subsequent Latent Variables for Females Latent Variable

Aggression T I

Dru g Use T 2

Delinquency T 2

Drug Use T j

Dru g use at T 2

0.34** (2.66) 0.28* (2.23) 0.31** (2.62) 0.26* (2.26) 0.14** (2.38) 0.23** (2.34)

0.82** (3.68) 0.90** (7.23) 0.77** (3.75) 0.42-(4.44) 0.69-(4.21)

0.00 - a 1.78** (3.19) 0.00 - a 0.90** (2.6 1)

1.87** (3.67) 0.47* * (4.62) 1.28** (3.96)

Delinquency at T 2 Drug use ar T 3 Delinquency at T , Drug use at T 4 Delinquency at T 4

D elinqu ency T,

Drug Use T 4

0.00

-

a

0.51** (3.85)

0.71** (2.81)

Note: Ent ries in parenthe ses are the t values of the total effects reponed. T he total effect of a delinqu ency variable on the subsequent latent drug variable is zero by virtue of the specification of the model in Figure 2. * P < .05; ** P < .01. a

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statistically significant. The total effect of earlier delinquency on later delinquency was significantly positive.

DISCUSSION

In this report , we build upon and extend earlier work by investigating the role of childhood aggression on young adult drug use and delinquency (T 4 ) . The results of the present study lend partial support to the notion of consistency between the hypothesized model and the findings. These findings can be discussed in four areas: (1) findings related to aggression; (2) the stability of drug use and delinquency extending to young adulthood (T 4 ) ; (3) the relationship between drug use and delinquency; and (4) comparison of male and female results. With respect to aggression, the results do support the importance of childhood aggression. The findings indicate that aggression during childhood has adverse effects on adolescent delinquency. In a combined model of males and females, the effect of childhood aggression on adult drug use and delinquency was significant. Furthermore, there were no significant gender differences in the direct effects of childhood aggression on adult drug use and delinquency. The results of the present study support and extend earlier findings, demonstrating that the presence of early disruptive characteristics such as fighting is related to later substance use (Dobkin et al., 1995; Friedman et aI., 1991; Kellam et aI., 1983; Pulkkinen, 1983; Shedler and Block, 1990). Among both males and females, the network of relationships between earlier drug use at T z, T 3, and T 4, and later delinquency at T 3 and T 4, or the crosssectional relationship between drug use and delinquency at T z, T 3, and T 4, is also quite comparable . The model extending into young adulthood supports earlier findings regarding the stability of drug use and delinquency (McCord, 1988; Robins and Pryzbeck, 1985). Thus, with respect to both of these variables, the continuity between T 3 and T 4 replicates the continuity between T, and T 3 • Several interpretations of these findings are possible. Adolescents may be motivated to continue drug behavior because of the psychopharmacological effects of the drug. Then, too, the use of the drug may cause the adolescent to feel better about himself or herself, at least in the short run. The stability of delinquent behavior may also be related to the consequences of the behavior. For instance, engaging

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in delinquent behavior may satisfy important needs in the person, such as a need for power. Peer groups may be involved in fostering continuities in both drug use and delinquent behaviors. Deviant adolescents are more likely to participate in delinquent and/or drug-using peer groups which, in turn , may lead to greater delinquency and drug use in the adolescent. Our results suggest that such processes extend well into young adulthood, whereas our earlier findings focused on adolescence. Our results showed that the age differences among the subjects became less important as the subjects became older, until there was no association of drug use with age at T 4 for both males and females, as expected. Our findings further showed that drug use at T z had a significant positive total effect on T 3 drug use, and T 3 drug use had a significant total effect on T 4 drug use. Our findings support our hypothesized in-time relations between drug use and delinquency. This research extends the earlier findings at T z and T 3 into T 4 • The model extends to young adulthood, namely our early and late adolescent findings regarding the relationship between drug use and delinquency. Thus, Figures 2 and 3 indicate that with in T z, T 3, and T 4 , drug use has an adverse impact on delinquency. In addition to the within-time relationships between drug use and delinquen cy, the total effects analyses, as noted below, point to relationships across time (i.e., T 4 delinqu ency is related to earlier T z and T 3 drug use, as well as to contemporaneous drug use). Stacy and Newcomb (1995) recently reported that adolescent drug use significantly predicted crimin al deviance in adulthood. Our study is one of only a limited number of studies spann ing as long as a 20-year period and relating aggression, drug use, and delinquency. This enables us to examine the connection between drug use and delinquen cy at several critical stages of development in the youngster. This pattern ofconsistency of relationships from drug use to delinquency at T z, T 3 , and T 4 is replicated in both males and females, providing us with greater confidence in the validity of our findings. It may be that drug use patterns cause theft, vandalism, and aggression by reducing inhibitions in the adolescent and young adult. Adolescents may commit crimes in order to obtain money to purchase drugs. Drug use may cause adolescents to associate with other drug users who may also be delinquent. As noted by

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Kaplan (1995), through interaction with these adolescents or young adults, whether by a process of socialization or modeling, patterns of substance use learned via the group may transfer into delinquent behavior. Another mediating link between drug use and delinquency is the adolescent's relations with family members. Drug use may cause difficulty in the parent-child relation which, in turn, may be associated with a turning away from conventional attitudes and turning toward later delinquent behavior. Theories of delayed development (Baumrind and Moselle, 1985) or truncated development (Newcomb and Bentler, 1988a,b) suggest that a greater degree of polydrug involvement would predict later life problems, which may include the exhibition of deviant behavior. Drug use may interfere with the development of positive mediators, such as the development of social skills, coping abilities, and the qualities that lead to effective social role functioning in adulthood (Baumrind and Moselle, 1985; Newcomb and Bentler, 1988a). Overall, the findings suggest that the model for the males and females were similar. However, there were some exceptions. Consistent with the literature (Jersild et al., 1978), males tended to engage in more delinquent behavior than females. Higher SES was associated with more frequent drug use among females. The interpretations of these findings are not clear. Several investigators hypothesize that common biological, psychological, or social processes may underlie drug use and delinquent behaviors (e.g., Collins, 1988; Massey and Krohn, 1986; Robins, 1966, 1978). Our results indicate that although the relation between drug use and delinquency was quite strong, even when childhood aggression was controlled for, the relation does not merely reflect childhood aggression as a "common cause." Two methodological limitations of the study bear addressing. First, the sample is predominantly white. Future research will need to include other ethnic groups, to determine whether the results generalize to other ethnic groups. The second limitation is the unanticipated positive relation between SES and drug use at T 4 in the females. Since there was a negative relation between SES and drug use at T 3' the relation between SES and drug use would benefit from further exploration. The findings have several implications for prevention. First, drug use and delinquency in adolescence

cannot be taken lightly, since there is continuity of these behaviors into adulthood. Second, a decrease in childhood aggression should be associated with a corresponding decrease in adolescent and young adult drug use, Finally, at each developmental stage, a decrease in drug use is likely to be accompanied by a decrease in delinquent behavior.

REFERENCES Anglin MD, Speckart G (1988), Narcotics use and crime: a multisarnple, multi method analysis. Criminology 26: 197-233 Baumrind D, Moselle KA (1985), A developmental perspective in adolescent drug use. Adv Alcohol Substance Abuse 5:41-67 Block], Block]H, Keyes S (1988), Longitudinally foretelling drug usage in adolescence: early childhood personality and environmental ptecursors. Child Dev 59:336-355 Brook ]S, Cohen P (1992), A developmental perspective on drug use and delinquency. In: Advances in Criminological Theory, Vol. 3: Crime Facts, Fiction, and Theory, McCord J, ed. New Brunswick, N]: Transactions Publishers, pp 231-251 Brook ]S, Whiteman M, Finch S (1992), Childhood aggression, adolescent delinquency and drug use: a longitudinal study. J Gen Psychol 151:369-383 Clayton RR, T uchfeld BS (1982), The drug-crime debate. Obstacles to understanding the relationship. J Drug Issues 12:153-166 Cohen P, Brook ]S (1987), Family factors related to the persistence of psychopathology in childhood and adolescence. Psychiatry 50:332-345 Cohen P, Srruening EL, Muhlin GL, Genevie LE, Kaplan SR, Peck HB (1989), Community stressors, mediating conditions and well-being in urban neighborhoods. J Community Psychol10:377-391 Collins]S (1988), Suggested explanatory frameworks to clarify the alcohol use/violence relationships. Contemp Drug ProblI5:107-121 Crawford A, Hinton ]W, Doherty C], Dishman D], Mulligan PE (1982), Alcohol and crime: 1. Self-reponed alcohol consumption of Scottish prisoners. J Stud Alcohol 43:610-613 Dobkin PL, Tremblay RE, Masse LC, Vitaro F (1995), Individual and peer characteristics in predicting boys' early onset of substance abuse: a seven-year longitudinal study. Child Dev 66:1198-1214 Eron LD, Huesmann LR (1990), The stability of aggressive behavior-even into the third generation. In: Handbook ofDeoelopmental Psychopathology, Lewis M, Miller SM, eds. New York: Plenum Press, pp 147-156 Fagan] (1989), Intoxication and aggression. In: Drugs and Crime (Crime and Justice: An Annual Review 0/Research, Vol 13), Wilson ]Q, Tonry M, eds. Chicago: Universiry of Chicago Press Friedman AS, Bransfield SA, Tomko LA, Katz S (1991), Early childhood and maternal antecedents to drug use. J Drug Educ 21:313-331 Hammersley R, Forsyth A, Morrison V, Davies ]B (1989), Relarionship berween crime and opioid use. Br J Addict 84:1029-1043 Hawkins ]D, Catalano RF, Miller ]Y (1992), Risk and protective factors for alcohol and other drug problems in adolescence and early adulthood: implications for substance abuse prevention. Psychol Bull 112:64-105 Hawkins ]D, Lishner DM, Jensen ]M, Catalano RF (1987), Delinquents and drugs: what the evidence suggests about prevention and treatment programming. In: Youth at High Risk [or Substance Abuse, Brown BS, Mills AR, eds. Rockville, MO: NIOA, pp 81-133 ]ersild AT, Brook ]S, Brook DW (1978), The Psychology 0/ Adolescence. New York: MacMillan ]oreskog KG, Sorbom D (1988), LISREL VII: A Guide to the Programs and Applications. Chicago: SPSS Kandel D, Simcha-Fagan 0, Davies M (1986), Risk factors for delinquency and illicit drug use from adolescence to young adulthood. J Drug Issues 16:67-90 Kaplan HB, ed (1995), Drugs, Crime and Other Deviant Adaptations: Longitudinal Studies. New York: Plenum

J. AM. ACAD. CHILD ADOLESC. PSYCHIATRY. 35:12, DECEMBER 1996

1591

BROOK ET AL.

Kellam SG, Brown CH, Rubin BR, Ensminger ME (1983), Paths leading to teenage psychiatric symptoms and substance use. Developmental epidemiological studies in Woodlawn. In: Childhood Psychopathology and Development, Cuze SB, Earls FJ, Barrett JE, eds. New York: Raven Press, pp 17-51 Kogan L, Smith J, Jenkins S (1977), Ecological validity of indicated data as predictors of survey findings. J Soc Serv Res 1:117-132 Massey JL, Krohn MD (1986), A longitudinal examination of an integrated social process model of deviant behavior. Soc Forces 65:106-134 McCord J (1988), Identifying developmental paradigms leading to alcoholism. J Stud Alcohol 49:357-362 Newcomb MD, Bentler PM (1988a), Consequences ofAdolescent Drug Use: Impact on the Lives ofYoungAdults. BeverlyHills, CA: Sage Publications Newcomb MD, Bentler PM (1988b), Impact of drug use and social support on problems of young adults: a longitudinal study. J Abnorm PsychoI97:64-75 Olweus D (1980), Bullying among school boys. In: Children and Violence, Barnen R, ed. Stockholm: Academic Literature, pp 259-279 Pulkkinen L (1983), Youthful smoking and drinking in a longitudinal perspective. J Youth Adolesc 12:253-283 Robins LN (1966), Deviant Children Grow Up. Baltimore: Williams & Wilkins Robins LN (1978), Sturdy childhood predictors of adult anti-social behavior: replications from longitudinal studies. PsycholMed 8:611-622

1592

Robins LN, Pryzbeck TR (1985), Age of onset of drug use as a factor in drug and other disorders. In: Etiology of Drug Abuse: Implications fOr Prevention (NIDA Research Monograph 56, DHHS Publication ADM 85 1335), Jones CL, Battjes RJ, eds. Washington, DC: US Government Printing Office, pp 178-192 Robins LN, Wish E (1977), Childhood deviance as a developmental process: a study of223 urban black men from birth to 18. SocForces 56:448-473 Shedler J, Block J (1990), Adolescent drug use and psychological health: a longitudinal inquiry, Am PsychoI45:612-630 Smith SS, Newman JP (1990), Alcohol and drug abuse-dependence disorders in psychopathic criminal offenders. J Abnorm PsychoI99:430-439 Stacy AW, Newcomb MD (1995), Long-term social-psychological influences on deviant attitudes and criminal behavior. In: Drugs, Crime, and Other Deviant Adaptations: Longitudinal Studies, Kaplan H, ed. New York: Plenum, pp 99-127 Urban J, Carlson F, Egeland B, Sroufe LA (1991), Patterns of individual adaptation across childhood. Dev PsychopathoI3:345-450 White HR (1990), The drug use-delinquency connection in adolescence. In: Drugs, Crime, and the Criminal Justice System, Weisheit R, ed. Cincinnati: Anderson Publishing Company and Academy of Criminal Justice Sciences Wilson JQ, Herrnstein R] (1985), Crime and Human Nature. New York: Simon & Schuster

]. AM. ACAD. CHILD ADOLESC. PSYCHIATRY, 35:12, DECEMBER 1996