Adolescent marijuana use: family but not peer use is associated when developing a dependence

Background: Marijuana use has been studied mainly in the U.S. and some European, lacking of cultural diversity, as well as made the comparison between users to non-users, but not between users with that present or not dependence. Thus, the research aims were to examine whether (1) family and peer marijuana use are related to adolescent marijuana use in Chile, (2) family and peer use are associated with adolescent dependence in adolescents using marijuana, and (3) the adolescent’s age moderates the association between family or peer use and adolescent use and dependence. Methods: 4,413 adolescents, aged 12-19 were included from the Chilean National Survey on Drug Use (surveys 2008 and 2010). It was conducted a cross-sectional study using regression analyses to measure the association between adolescent marijuana use and dependence (ICD-10 criteria), family and peer marijuana use, and the interaction of an adolescent’s age with family and peer marijuana use. Findings: When adolescents have someone at home or a close friend using marijuana they were five or eight times more likely to use the drug (p< .001). In cases of adolescents using marijuana, having someone at home using marijuana they were three times more likely to present a dependence (p= .015), but no significant relationship was found for peer use (p= .683). No statistical interactions between family or peer use and age were found. Discussion: Family and peer marijuana use were associated with adolescent marijuana use, but only family marijuana use was statistically associated with adolescent marijuana dependence.