Selection and Socialization Influences on Adolescent Alcohol Use: The Individual and Joint Contexts of Neighborhood Disadvantage and Population Density.

: Neighborhood disadvantage (ND) and population density (PD) are two community characteristics contextualizing friends' influence on adolescent alcohol use. However, these community characteristics are rarely examined for potential joint contributions, although it is possible that the way friends are selected or influence alcohol use are shaped by both ND and PD. In addition, prior studies examining ND or PD contexts on friend influence rarely discern between socialization and selection. : The current study examined how selection and socialization influences on adolescent alcohol use are shaped by unique and joint contexts of ND and PD. : Adolescents from Waves I and II of the National Longitudinal Study of Adolescent and Adult Health (Add Health) were included in three models assessing friends' socialization of alcohol us initiation and binge drinking, and selection of drinking friends. ND and PD were tested for mediation and moderation individually and jointly. : Results indicated that socialization of drinking initiation was stronger in high ND contexts, and that continued binge drinking was stronger in low ND contexts. PD indirectly influenced socialization of initiation and binge drinking maintenance via a negative association with number of drinking friends. PD and ND jointly influenced the association between initial binge drinking and next-year selection of drinking friends, such that selection was stronger within areas related to lower levels of drinking friends. : Current results indicate that PD and ND shape friends' influence on alcohol use in unique ways. These must be accounted for to better understand bidirectional effects of friend influence.