Abstract
Peer influence is one of the most proximal risk factors for adolescent substance use, and decades of theoretical and empirical research point to the importance of disentangling two interrelated processes that often co-occur: (1) peer selection is the process whereby adolescents choose to interact with one another; and (2) peer socialization is the process whereby individual behavior is shaped over time. Recent advancements in social network analyses, including the application of stochastic actor based models to developmental studies, have helped to disentangle the contributions of peer selection and socialization to adolescent substance use. The current study is the first systematic review of this literature, aiming to identify the extent to which adolescent substance use is associated with peer selection and socialization and highlighting patterns in study design across studies. Forty studies that met inclusion criteria were identified and systematically coded for study design characteristics (e.g., number of time points; number of covariates) and significant peer selection and socialization effects by substance use outcome. This review found support for peer selection effects on adolescent alcohol and tobacco use. Additionally, most studies reported peer socialization effects for adolescent alcohol use. However, relatively few studies reported socialization effects for tobacco use. Few studies reported on the peer effects associated with adolescent drug use. Variations in study design, including variations in the bounds of the network and in the covariates included in modeling, helped to identify areas for future research. Future research that helps to further clarify the roles of specific peer selection and socialization mechanisms will help with the development and refinement of prevention and intervention programs focused on reducing adolescent substance use.