Do peers' parents matter? A new link between positive parenting and adolescent substance use.

Objective: Although studies have demonstrated that an adolescent's parents and friends both influence adolescent substance use, it is not known whether the parenting experienced by one's friends also affects one's own use. Drawing on conceptions of shared parenting and the tenets of coercion theory, we investigated the extent to which three domains of parenting behaviors (parental knowledge, inductive reasoning, and consistent discipline) influenced the alcohol, cigarette, and marijuana use of not only their own adolescent children but also of members of their adolescents' friendship groups.
Method: Analyses of friendship nominations within each of two successive ninth-grade cohorts in 27 Iowa and Pennsylvania schools (N = 7,439 students, 53.6% female) were used to identify 897 friendship groups. Hierarchical logistic regression models were used to examine prospective associations between 9th-grade friendship group-level parenting behaviors and adolescent self-reported alcohol, cigarette, and marijuana use in 10th grade.
Results: Adolescent substance use in 10th grade was significantly related to parenting behaviors of friends' parents, after controlling for adolescents' reports of their own substance use and their own parents' behaviors at the 9th grade level. These associations were particularly strong for parents' knowledge about their children and use of inconsistent discipline strategies. Significant interaction effects indicated that these relationships were strongest when adolescents received positive parenting at home. Some, but not all, of the main effects of friends' parents' parenting became nonsignificant after friends' substance use in ninth grade was included in the model.
Conclusions: The findings suggest that the parenting style in adolescents' friends' homes plays an important role in determining adolescent substance use. Implications of the joint contribution of parents and peers for prevention and intervention are discussed.