Predictors and consequences of simultaneous alcohol and cannabis use in adolescents.

BACKGROUND/AIMS: The simultaneous use of alcohol and cannabis is common among adolescents, but has been little studied. In this study, we examine predictors and consequences of this behavior in a population-based sample of high school students. METHOD: Self-reports were obtained from students in Quebec (Canada) followed throughout high school (N=6589). Logistic regressions were used to test the association between individual, family, and peer-related predictors in grades 7-8 and simultaneous alcohol and cannabis use in grade 10, as well as between simultaneous alcohol and cannabis use in grade 10 and experiencing 3 or more substance-related problems of various types (legal, physical, etc.) in grade 11. RESULTS: Most predictors in grades 7-8 were associated with simultaneous alcohol and cannabis use in grade 10. Only variables reflecting early-onset substance use involvement - alcohol intoxication, cannabis use, and drug use by close friend(s) - remained predictive in a multivariate model. Simultaneous alcohol and cannabis use was associated with increased substance-related problems in grade 11, above and beyond baseline problems and the concurrent use of the two substances in separate episodes in grade 10. CONCLUSIONS: Simultaneous alcohol and cannabis use 1) is anticipated by multiple psychosocial risk factors which come together with individual and peer substance use in early high school and 2) is independently predictive of subsequent substance-related problems. Providing adolescents with adequate information regarding the potential harm of simultaneous use may be a useful prevention strategy.

Preventing disruptive boys from becoming heavy substance users during adolescence: a longitudinal study of familial and peer-related protective factors.

Childhood disruptiveness is one of the most important antecedents of heavy substance use in adolescence, especially among boys. The first aim of the present study is to verify whether parental monitoring and friend conventionality protect disruptive boys from engaging in heavy substance-use in adolescence. The second purpose is to examine whether these protective effects are strengthened by attachment to parents or friends respectively. Finally, the third objective is to verify whether the expected protective effect of parental monitoring could be mediated through exposure to conventional friends. A sample of 1037 boys from low socioeconomic neighbourhoods was followed from childhood (age 6) to adolescence (age 15). Parent, teacher, and self-reported measures were used to measure disruptiveness, parental monitoring, family attachment, friend conventionality, and attachment to friends. Results suggest that parental monitoring and friends' conventionality mitigated the relationship between childhood disruptiveness and adolescence heavy substance use. Exposure to conventional friends further mediated the protective effect of parent monitoring. The postulated enhancement of attachment quality on the protective effect of parents or peer behaviors was not confirmed, but low attachment was related to heavier substance use in highly monitored disruptive boys. Parental monitoring, family attachment, and peer conventionality are factors amenable to intervention, and thus represent promising targets for future prevention strategies aimed at-risk boys. Our results underscore the importance of simultaneously addressing the behavioral and the affective dimensions in interventions with parents.