Marijuana Use and Dependence in Chilean Adolescents and Its Association with Family and Peer Marijuana Use.

PURPOSE: The purpose of the study is to examine (1) whether family and peer marijuana use are independently related to adolescent marijuana use in Chile, (2) whether family and peer marijuana use are associated with adolescent marijuana dependence in adolescents using marijuana, and (3) whether the adolescent's age moderates the association between family or peer use and adolescent marijuana use and/or dependence.

METHOD: This study used data from the National Survey on Drug Use in the General Population in Chile (a cross-sectional observational study), which was conducted in 2008 and 2010 in 4413 adolescents aged 12-19. Adolescents answered questions about their past-year marijuana use and dependence (ICD-10 criteria) and the marijuana use of their family and peers. Logistic regressions were performed while controlling for confounders.

RESULTS: Adolescents who had a family member who used marijuana were five times more likely to use the drug. Adolescents with a close friend who used marijuana were eight times more likely to use marijuana. When adolescents were using marijuana, they were three times more likely to be dependent if they had a family member who used the drug. However, no significant relationship was found between peer use and dependence. No statistically significant interactions were found between family or peer use and age.

CONCLUSION: Family and peer marijuana use was independently associated with adolescent's past-year marijuana use; however, only family marijuana use was statistically associated with adolescent's marijuana dependence.