Peer influences are central to developmental models of substance use. The findings suggest that close friends who use substances may have a particularly strong influence on heavy episodic drinking behaviors during adolescence and young adulthood, even after controlling for the perception of substance use among the larger peer group and self-rated parental knowledge. The increased autonomy this developmental period may afford greater opportunity to engage in drinking behaviors, especially when close friends model and reciprocate such behaviors via socialization effects (Shanahan and Hofer, 2005). Proximal social structures may also be more salient predictors of heavy episodic drinking than distal ones, as individuals are more pressured to support, provide, and appease in closer relationships (Brown et al., 1997). Other studies found that different peer contexts (i.e., close friends, peer groups, and social crowds) demonstrate separable effects on adolescent substance use, and that the association between substance use among close friends and the adolescents’ own substance use was moderated by their peer group status (Hussong, 2002), although our own data did not reveal three-way interactive effects1. The absence of a main effect
