Young people who start to smoke tobacco early risk ending up with early cannabis use

According to a study, Externalizing Behavior Problems and Cigarette Smoking as Predictors of Cannabis Use: The TRAILS Study, published in the Journal of the American Academy of Child and Adolescent Psychiatry (Volume 49, Issue 1, pages 61-69), early smoking onset is a powerful predictor of later cannabis initiation independent of preceding externalizing behavior problems.

Dutch adolescents (N = 1,606; 854 girls and 752 boys) from the TRacking Adolescents’ Individual Lives Survey (TRAILS) ongoing longitudinal study were examined at baseline (ages 10–12 [T1]) and at two follow-up assessments (ages 12–15 [T2] and 15–18 [T3]). The analysis focused on DSM-IV externalizing behavior (conduct, attention deficit hyperactivity, and oppositional) problems at T1, assessed by the Youth Self Report and the Child Behavior Check List, on self-reported ever smoking at T2, and on cannabis use at T3.

Our findings challenge the view that externalizing behavior problems directly predict cannabis initiation. Such associations were inconsistent across informants and sexes and were often mediated by earlier smoking. Although externalizing behavior problems are important as a starting point for substance use trajectories, early-onset smoking should be identified as an important marker of cannabis use risk, say the scientists from the Netherlands and Finland.