Peer influence and adolescent substance use: A social networks analysis

The relationship between delinquency involvement and association with delinquent peers is well known among theorists and researchers. Although friendship relations are an important aspect of adolescent life, only rarely is the structure of these relations examined systematically. This study uses social network analysis as a tool to examine how association with peers affects adolescent substance use.Data for the study are from the National Longitudinal Study of Adolescent Health (Add Health). The network characteristics examined include Centrality, Prestige, Density, and Heterogeneity. Two types of analyses are presented: a quantitative analysis and a case study. The quantitative study includes a regression analysis of the effects of the social network variables on imminent and later substance use, and an analysis of use trajectory. The case study provides a visual representation of the link between friendship groups and substance use.The results from the quantitative study suggest that of the four network variables examined only Prestige and Density have significant short-term effects on substance use. Prestige has a positive effect and Density has a negative effect. The results regarding Centrality and Heterogeneity are inconclusive although Centrality does appear to have a negative effect on substance use when the race/ethnicity of the respondents is controlled. Heterogeneity has a significant positive effect only for future illegal substance use. The trajectory analyses reveal that trajectories for alcohol use and marijuana use trend in opposite directions. The trajectory for alcohol use shows an increasing number of users and levels of individual use, while that for marijuana use shows a decrease in both numbers of users and levels of use. The case study examines the entire network of a small school. The results are generally consistent with and illustrative of the results from the quantitative study. In addition, the results suggest that individuals who are in structurally similar positions in a friendship group engage in similar levels of substance use.The research highlights the importance of peer network structures for understanding the relationship between peer association and substance use. Limitations of the study are discussed as are policy implications. Recommendations for future research are also suggested.