The impact of peer social networks on adolescent alcohol use initiation

Early adolescent alcohol use is a major public health problem. Drinking before the 14th birthday is associated with a fourfold increase in risk of alcohol dependence in adulthood. The objective of this study is to evaluate the association between adolescent social network characteristics and alcohol initiation prospectively over time.

The study analyzes data from the National Longitudinal Study of Adolescent Health, a nationally representative survey of 7th- through 11th-grade students enrolled between 1995 and 1996. Generalized estimating equations are used to model the risk of alcohol use initiation at 1-year follow-up among nondrinkers at wave 1 of the study.

Both an adolescent's friends' alcohol use and the adolescent's social network characteristics displayed an independent main effect on alcohol initiation. In comparison with abstainers, alcohol initiators had more popular friends as measured by more peer nominations as friends (indegree) and having more friends up to 3 steps removed (3-step reach), and more friends who drank. An adolescent's risk of alcohol use onset increased 13% (95% CI, 4%-22%) for every additional friend with high indegree, 3% (95% CI, 0.3%-6%) for every additional 10 friends within 3-step reach, and 34% (95% CI, 14%-58%) for each additional friend who drank alcohol, and after controlling for confounders.

The findings suggest that, in addition to well-established demographic risk factors, adolescents are at heightened risk of alcohol use onset because of their position in the social network in relationship to their friends and the friends of their friends.