Two processes have been proposed to account for strong associations between peer and adolescent behavior: selection and socialization. Selection models propose that delinquent involvement and substance use lead to friendships with peers who support delinquency and substance use, while peer socialization models suggest that certain friendships lead to delinquency and substance use. Research generally supports both selection and socialization (Mercken et al. 2009), but socialization is more prominent in the early stages of alcohol and drug use (Wills and Cleary 1999). Longitudinal studies support the evidence of socialization effects from peer drug use to adolescent substance use (Wills and Cleary 1999).
