Contextual risks linking parents' adolescent marijuana use to offspring onset.

OBJECTIVE We studied the extent to which parent marijuana use in adolescence is associated with marijuana use onset in offspring through contextual family and peer risks. METHOD Fathers assessed (n=93) since childhood, their 146 offspring (n=83 girls), and offspring's mothers (n=85) participated in a longitudinal study. Using discrete-time survival analysis, fathers' (prospectively measured) and mothers' (retrospective) adolescent marijuana use was used to predict offspring marijuana use onset through age 19 years. Parental monitoring, child exposure to marijuana use, peer deviance, peer marijuana use, and perceptions of parent disapproval of child use were measured before or concurrent with onset. RESULTS Parents' adolescent marijuana use was significantly associated with less monitoring, offspring alcohol use, the peer behaviors, exposure to adult marijuana use, and perceptions of less parent disapproval. Male gender and the two peer behaviors were positively associated with children's marijuana use onset, controlling for their alcohol use. Parents' adolescent marijuana use had a significant indirect effect on child onset through children's deviant peer affiliations and a composite contextual risk score. CONCLUSIONS Parents' histories of marijuana use may contribute indirectly to children's marijuana use onset through their influence on the social environments children encounter; specifically, those characterized by more liberal use norms, exposure to marijuana use and deviant and marijuana-using peers, and less adult supervision. Given that alcohol use onset was controlled, findings suggest that the contextual factors identified here confer unique risk for child marijuana use onset.