Epidemiology of Youth Drug Abuse

Research Findings from September, 2004 Director's Report

This section lists selected summaries from NIDA funded research projects that investigate the epidemiology, etiology, and prevention research. The summaries provided were selected from recent issues of the Director's Report to the National Advisory Council on Drug Abuse. For a more comprehensive listing of NIDA funded projects see the Director's Report.

Prenatal Marijuana Exposure and Academic Achievement at Age 10 Years

University of Pittsburgh researchers have reported their latest findings from a longitudinal cohort study of children exposed to marijuana in utero. In this study, women were interviewed about their substance use at the end of each trimester of pregnancy, and at multiple times during the child's development. The children were assessed on physical, emotional, and cognitive development at 8 and 18 months, and at 3, 6, 10, 14, and 16 years postpartum. This report provides findings on academic achievement at age 10 (606 children were assessed), using the Wide Range Achievement Test-Revised (WRAT-R), the reading comprehension subtext of the Peabody Individual Achievement Test-Revise (PIAT-R), and teacher reports of child performance in school. As a group, the women were of lower socioeconomic status, high-school-educated, light-to-moderate users of marijuana and alcohol, and equally distributed in terms of race/ethnicity (Caucasian and African-American). Exposure to one or more marijuana joints per day during the first trimester predicted deficits in WRAT-R reading and spelling scores, and a lower rating on the teachers' evaluations of the children's performance. These associations existed when home environment, race/ethnicity, socioeconomic status, and other prenatal substance exposure were controlled. However, these associations were mediated by effects of first-trimester marijuana exposure on the children's symptoms of depression and anxiety. Second-trimester marijuana use was associated with reading comprehension and underachievement. Exposure to alcohol during the first and second trimesters predicted poorer teacher ratings of overall school performance, whereas second-trimester binge drinking predicted lower reading scores. There was no interaction between prenatal marijuana and alcohol exposure. Each was an independent predictor of aspects of academic performance. The investigators compared their findings to those of the other cohort study of prenatal marijuana exposure reported in the literature, and they discussed possible reasons for differences in findings on school performance between the two studies. The investigators also discuss the limitations of the analyses and of the generalizability of the findings. Goldschmidt, L., Richardson, G.A., Cornelius, M.D., and Day, N.L. Prenatal Marijuana and Alcohol Exposure and Academic Achievement at Age 10. Neurotoxicology and Teratology, 26, pp. 521-532, 2004.

Prevalence of Marijuana Use Disorders in the United States: 1991-1992 and 2001-2002

Among illicit substance use disorders, marijuana use disorders are the most prevalent in the population. Yet, information about the prevalence of current DSM-IV marijuana use disorders and how prevalence has changed is lacking. To examine changes in the prevalence of marijuana use, abuse and dependence in the United States between 1991-1992 and 2001-2002, face-to-face interviews were conducted in two large national surveys conducted ten years apart: the 1991-1992 National Longitudinal Alcohol Epidemiologic Survey (NLAES: n=42,862), and the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC: n = 43,093). Among the adult U.S. population, the prevalence of marijuana use remained stable at about 4.0% over the past decade. In contrast, the prevalence of DSM-IV marijuana abuse or dependence significantly (p < 0.05) increased between 1991-1992 (1.2%) and 2001-2002 (1.5%), with the greatest increases observed among young Black men and women and young Hispanic men (p < 0.01). Further, marijuana use disorders among marijuana users significantly increased (p < 0.01) in the absence of increased frequency and quantity of marijuana use, suggesting that the concomitant increase in potency of _9-THC may have contributed to the rising rates. Despite the stability in the overall prevalence of marijuana use, more adults in the U.S. had a marijuana use disorder in 2001-2002 than in 1991-1992. Increases in the prevalence of marijuana use disorders were most notable among young Black men and women and young Hispanic men. Although rates of marijuana abuse and dependence did not increase among young white men and women, their rates have remained high. The results of this study underscore the need to develop and implement new prevention and intervention programs targeted at youth, particularly minority youth. Compton, W.M., Grant, B.F., Colliver, J.D., Glantz, M.D. and Stinson, F.S. Prevalence of Marijuana Use Disorders in the United States: 1991-1992 and 2001-2002. Journal of the American Medical Association, 291(17), pp. 2114-2121, 2004.

Neighborhood Environment and Opportunity to Try Methamphetamine ("Ice") and Marijuana: Evidence from Guam in the Western Pacific Region of Micronesia

This study examines the occurrence of youthful drug involvement among youths living in village and metropolitan regions of Guam during 1998. A probability sample of 776 high school students living in Guam, Micronesia, completed a self-report anonymous survey, one that assessed their village and metropolitan neighborhood environments as well as drug involvement. Results indicate that higher levels of neighborhood disadvantage were associated with youths being more likely to have been offered a chance to try drugs. This study adds new evidence on the potential importance of environmental and psychosocial contexts of neighborhood environment that might help account for the nonrandom distribution of youthful drug involvement. Storr, C.L., Arria, A.M., Workman, Z.R. and Anthony, J.C. Substance Use and Misuse, 39(2), pp. 253-276, 2004.

Early Adolescent Through Young Adult Alcohol and Marijuana Use Trajectories

This study takes a developmental approach to subgrouping and examines the trajectories of substance use from early adolescence through young adulthood among a community sample of 481 individuals. The patterns of use were examined, subgroups were identified separately for men and women and for alcohol and marijuana, and psychosocial predictors and psychopathology outcomes that differentiated the groups were identified. The results revealed three substantially overlapping subgroups for both alcohol and marijuana: early onset, late onset, and nonuser. Although the general patterns of which dependent variables were related to group were similar for alcohol and marijuana, a closer examination revealed important subgroup differences. For alcohol use, the early-onset group was more dysfunctional in terms of predictors and outcomes whereas the late-onset and nonuser groups were better adjusted. In contrast, for marijuana, the early- and late-onset groups were both more dysfunctional than the nonuser group. In a final analysis, the researchers examined the predictive utility of our developmental approach to subgrouping compared to a traditional, static approach. Flory, K., Lynam, D., Milich, R., Leukefeld, C., and Clayton, R. Early Adolescent through Young Adult Alcohol and Marijuana Use Trajectories: Early Predictors, Young Adult Outcomes, and Predictive Utility. Development and Psychopathology, 16(1), pp. 193-213, 2004.

Transitions to Drug Use

This study examines whether patterns in the transition from alcohol and tobacco in the Mexican State of Morelos, Mexico are similar to those observed in other countries. The data were from a representative sample of youth age 11-21 (n=13,105), who participated in a paper-and-pencil survey in middle schools, high schools, and colleges in the State of Morelos, Mexico. Drug use was assessed via the standardized instrument most used in Mexican student surveys. Cox's models for discrete-time survival analyses, stratified by school and age group were used to estimate the risk of drug use in relation to early or non early alcohol and tobacco use initiation by gender, while accommodating the complex survey design. The study findings suggest that about five percent of the students were estimated to have used drugs in their life. Male early users of alcohol or tobacco were more likely to use other drugs, compared to students who did not have an early alcohol or tobacco onset. Recommendations for future studies includes an exploration of the role of social mechanisms and their relationship to patterns of drug involvement, even in the context of important differences in rates of drug use. Wagner, F.A., Velasco-MondragÑn, H.E., Herrera-Vazquez, M., Borges, G. and Lazcano, E. Early Alcohol and Tobacco Use and Transition to Other Drug Use Among Students in the State of Morelos, Mexico. Drug and Alcohol Dependence. Corrected proof available online 24 August 2004.

Correlates of Aggression in African American and Puerto Rican Children

This cross-sectional study examines the interrelationship of psychosocial domains as they relate to aggression in a sample of African American and English-speaking Puerto Rican children living in New York City. The sample included 80 biological children of African American and Puerto Rican young adults who have participated in the authors ongoing longitudinal study and 77 mothers or mother substitutes (rearing mothers) of those children. Hierarchical multiple regression analysis was performed, with childhood aggression as the dependent variable and the following domains as independent variables: child and maternal personality attributes; mother-child relationship; ethnic identification and discrimination; and the partner/marital relationship. The results indicated that: (a) the child's personality and maternal attributes were significantly related to the child's aggression, despite control on all the other domains; (b) the ethnic identification and discrimination domain was no longer related to the child's aggression with control on the mother-child relationship domain or the child's personality domain. The findings have implications for clinical practice and public policy, and provide significant insights into childhood risk factors that need to be altered to reduce physical aggression. Brook, J.S., Rosenberg, G., Brook, D.W., Balka, E.B. and Meade, M. Correlates of Aggression in African American and Puerto Rican Children. Journal of Genetic Psychology, 165(2), pp. 185-202, 2004.

Illicit Drug Use and Risky Sexual Behavior Among African American and Puerto Rican Urban Adolescents: The Longitudinal Links

This study assessed whether (a) early illicit drug use predicts later risky sexual activity; (b) early risky sex predicts later illicit drug use; and (c) common factors affect both risky sex and illicit drug use. African American and Puerto Rican youth completed questionnaires in their classrooms at Time 1 (T1) and face-to-face interviews five years later at Time 2 (T2). Logistic regression analyses showed the association between T1 illicit drug use and T2 risky sexual activity and between T1 risky sexual behavior and T2 illicit drug use. With few exceptions, T1 illicit drug use was associated with all of the T2 risky sexual behaviors. After controlling for demographic factors, multiple sex partners at T1 was not related to illicit drug use at T2. Condom use at T1 was related to illicit drug use at T2, whereas sexually transmitted diseases and early pregnancy were not. The findings indicated that assessments of and treatments for substance use should focus on the risky sexual behaviors that seem to accompany illicit drug use. Brook, J.S., Adams, R.E., Balka, E.B., Whiteman, M., Zhang, C. and Sugerman, R. Illicit Drug Use and Risky Sexual Behavior Among African American and Puerto Rican Urban Adolescents: The Longitudinal Links. Journal of Genetic Psychology, 165(2), pp. 203-220, 2004.

Risk-Taking Behaviors Among African American Adolescents

This study explores the relationship between peer status, peer groups' social influence and risk-taking behavior in an urban sample of 647 African American seventh grade students. Highest rates of problem behaviors were seen in those youth who were both highly liked and highly disliked by other youth. Findings also revealed contrasting patterns of peer group leadership. The more controversial the youth the more likely the involvement in deviant peer groups. Results highlight the importance of controversial status students as key influence agents during early adolescence, and implications for prevention interventions to reduce adolescent problem behaviors. Miller-Johnson, S., Costanzo, P.R., Cole, J.D., Rose, M.R., Browne, D.C., and Johnson, C. Peer Social Structure and Risk-Taking Behaviors Among African American Early Adolescents. Journal of Youth and Adolescence, 32(5), pp. 375-384, 2003.

Drug Use Among American Indian Adolescents

This study examines the trends in drug use among American Indian adolescents attending school on or near the Indian reservations in the United States. The study provides comparisons between American Indian and non-Indian youth to assess their drug use and issues of prevention. Reliable and valid school administered surveys have been given every year for 25 years (1975 Ñ 2000) to representative samples of American Indian youth living on reservations, providing a continuous record of drug use. Comparisons are made with non-Indian youth with data from the Monitoring the Future project. From 1975 to 2000, reservation Indian youth show elevated levels of drug use for most illicit drugs compared with non Indian youth. Despite higher levels of use, the trends showing increases and decreases in use over time mirror that by non-Indian youth. Indian youth who use drugs can be divided into two groups, moderate category and high levels of use. The number of youth in the moderate category vary overtime, whereas the number in the high level category are relatively constant. There is a clear need for intensive efforts to reduce the levels of drug use among Indian youth, however future interventions must address the differing characteristics of high and moderate risk users of drugs. Beauvais, F., Jumper-Thurman, P., Helm, H., Plested, B. and Burnside, M. Surveillance of Drug Use Among American Indian Adolescents: Patterns Over 25 Years. Journal of Adolescent Health, 34, pp. 493-500, 2004.

Violence Prevention among African American Adolescent Males

This study tests whether the efficacious, multi-year Aban Aya intervention has significant effects on the proposed mediating variables and whether the significant preventive effects in reducing violence found in previous analyses are mediated by changes in proposed mediators. Five hundred seventy-one African American adolescent males participated in this randomized trial. Multi-level modeling techniques were used to ascertain both intervention and mediated effects. The intervention significantly reduced the rate of growth of violence and five social and psychological factors in the treatment group relative to the control group. Four of these social and psychological factors, behavioral intentions, attitudes toward violence, estimates of peers' behaviors, and estimates of best friends' behaviors, were found to be complete mediators between the intervention and its preventive effects. Ngwe, J.E., Liu, L.C., Flay, B.R., Segawa, E. and the Aban Aya coinvestigators. Violence Prevention among African American Adolescent Males. American Journal of Health Behavior, 28(Suppl 1), pp. S24-S37, 2004.

Social Assertiveness, Internalizing, and Gender Moderation Effects Of A Preventive Intervention

The current study investigated gender moderation of the longitudinal pathways from internalizing to both social competency and the initiation of substance use as well as the effects of a preventive intervention on that process. Rural Midwestern adolescents who were participating in a school-based preventive intervention study were an average of 12.3 years old at the pretest assessment. A latent growth curve comparison analysis found that internalizing was inversely related to initial levels of social assertiveness skill among girls. Internalizing was positively related to substance use initiation growth trajectories among girls. Girls who participated in the preventive intervention demonstrated a slower increase over time in substance use initiation and a faster increase in social assertiveness. Lillehoj, C.J., Trudeau, L., Spoth, R.and Wickrama, K.A.S. Internalizing, Social Competence, and Substance Initiation: Influence of Gender Moderation and a Preventive Intervention. Substance Use and Misuse, 39(6), pp. 963-991, 2004.

D.A.R.E Plus Is More Effective in Preventing Violence Among Boys Than Girls

Twenty-four middle schools were randomly assigned to: 1) DARE curriculum; 2) DARE Plus multi-component curriculum; or 3) control condition. Outcomes of the three conditions on violence-related behaviors were compared, and mediational analyses were conducted to examine how interventions reduced physical and verbal violence. Generally, boys demonstrated higher rates of violence and victimization than girls. Boys in the DARE Plus condition had a marginally significant lower number of verbally violent acts than boys in the control condition. Boys in the DARE Plus condition had a marginally lower number of physically violent acts than boys in the DARE condition. There were no significant differences between the DARE only and control groups. There were no significant differences between the three groups in victimization. The small behavioral effect that DARE Plus demonstrated on physical and verbal violence among boys was mediated by a decrease of norms that support violence, an increase in outcome expectancies about being violence-free, and an increase in parental consequences for fighting. DARE Plus was not as effective in preventing violence among girls, however, girls in the DARE Plus condition had significantly lower scores on the Victimization Scale than girls in the DARE only condition. Komro, K.A., Perry, C.L., Veblen-Mortenson, S., Stigler, M.H., Bosma, L.M., Munson, K.A. and Farbakhsh, K. Violence-related Outcomes of the DARE Plus Project. Health Education & Behavior, 31(3), pp. 335-354, 2004. Perceptions of Rural Parents Regarding Family-Focused Programs Data collected in the Promoting School-Community-University Partnership to Enhance Resilience (PROSPER) project during telephone interviews with 1,156 parents of sixth graders from 36 rural schools were used in multilevel structural equation modeling. Results of analyses show that: 1) parents considered their children to be at low risk for substance use; 2) parents perceived themselves to be effective in helping their children avoid maladaptive behaviors; 3) mothers perceived themselves to be more efficacious than did fathers; 4) parental efficacy perceptions inversely affected perceptions of child susceptibility; 5) parents' perceptions of child susceptibility positively affected perceived program benefits; and 6) higher perceived program benefits and higher perceived child susceptibility were associated with mothers, male children, single parents, lower household income, and lower parent education. Redmond, C., Spoth, R, Shin, C. and Hill, G. Engaging Rural Parents in Family-Focused Programs to Prevent Youth Substance Abuse. Journal of Primary Prevention, 24(3), Spring, 2004.

*Alcohol and Marijuana Use in Early and Late Adolescence

This study examined alcohol and marijuana use over a 9-year period between ages 11-12 and ages 19-21 using a community based dataset collected prospectively as part of the evaluation of Project DARE. Because the DARE intervention was found to have no effects on any program targets, this dataset provides an appropriate community sample for investigating developmental changes in drug use over time. 481 participants (50.17% male, 79.2% Caucasian) were interviewed once a year in the sixth through tenth grades and again at age 20. A growth mixture model approach was used to analyze interview data from 6 time points in an attempt to empirically identify subgroups of alcohol and marijuana users over time. Three subgroups were identified for both alcohol use and marijuana use: a group that initiated substance use in early adolescence (age 11-12), a group that initiated use in late adolescence/early adulthood (age 15-16), and an abstainer group. Several variables measured in early adolescence including school and church involvement, self-esteem, peer pressure resistance, sensation seeking, expectancies, and conduct problems significantly differentiated the alcohol and marijuana subgroups. The subgroups also differed significantly on young adult outcomes, including alcohol and marijuana dependence, antisocial personality disorder symptoms, and number of arrests. For alcohol use, the early-onset group was more dysfunctional in terms of early psychosocial risk factors and later deleterious outcomes whereas the late-onset and nonuser groups were better adjusted. In contrast, for marijuana, the early- and late-onset groups were both more dysfunctional than the nonuser group. Flory, K., Lynam, D., Milich, R., Leukefeld, C. and Clayton, R. Early Adolescent through Young Adult Alcohol and Marijuana Use Trajectories: Early Predictors, Young Adult Outcomes, and Predictive Utility. Development and Psychopathology, 16, pp. 93-213, 2004.

Spirituality and "Health-As-A-Value" Are Protective Against Teen Substance Use

This study investigated the influence of two potentially protective factors, Health-as-a-Value (HAV) and spirituality, on monthly alcohol, cigarette, and marijuana use in two multiethnic groups of adolescents varying in risk. Survey respondents included 382 students from continuation/alternative high school, a population considered at risk for drug use, and 260 students drawn from a medical magnet high school, and considered to be at lower risk. The data indicated that spirituality was protective against monthly alcohol use and marijuana use in the lower risk sample. In the higher risk sample, spirituality was protective against all monthly use. HAV was protective against monthly alcohol use in the low risk sample, and protective against all monthly use in the higher risk sample. When both constructs were entered into the same model, spirituality and HAV were independently protective of all monthly use for the higher risk sample and of monthly alcohol use in the lower risk sample, supporting the earlier finding that both are independently protective values. Thus, HAV and spirituality may be protective in various environments, independent of the level of use in the environment. Ritt-Olson, A., Milam, J., Unger, J.B., Trinidad, D., Teran, L., Dent, C.W., and Sussman, S. The Protective Influence Of Spirituality And "Health-As-A-Value" Against Monthly Substance Use Among Adolescents Varying In Risk. Journal Of Adolescent Health, 34 (3), pp. 192-199, 2004.

Agreement of Program Provider and Observer Ratings of School-Based Preventive Intervention Implementation & Relation to Youth Outcomes

Few prevention studies have examined the degree to which different measures of program implementation adherence predict youth outcomes. The current study was conducted with rural middle school youth participating in a longitudinal school-based preventive intervention program. Study participants' average age at the pretest assessment was 12.3 years. The association between program implementation ratings supplied by provider self-reports and trained independent observer reports were evaluated. In addition, the relationship between measures of implementation and youth outcomes were examined. Results indicated that although program providers tended to report higher implementation than independent observers, most ratings were correlated significantly across raters. Moreover, observer-reported implementation ratings significantly predicted several youth substance-related outcomes, while provider reported self-ratings did not. Findings suggest that there might be a social desirability bias in provider self-reported ratings of implementation and that caution must be used when interpreting self-reported ratings of implementation. Lillehoj, C.J., Griffin, K.W. and Spoth, R. Program Provider and Observer Ratings of School-based Preventive Intervention Implementation: Agreement and Relation to Youth Outcomes. Health Education and Behavior, 31(2), pp. 242-257, 2004.