Alcohol and sex: the influence of friendship networks on co-occurring risky health behaviors of U.S. adolescents

Background: U.S. adolescents face the reality that engaging in one risky health behavior facilitates co-occurring risky behaviors. Moreover, adolescents may change their behaviors to develop new friendships or to match the behavior of existing friends. These relationships among friends can lead to increase in risk-taking. Methods: Utilizing a nationally representative saturated sample (n=901) with friendship network data from two large schools in the Wave I of the National Longitudinal Study of Adolescent Health (Add Health), this study examined the influence of friendship network structure upon adolescents’ sexual intercourse and alcohol consumption in tandem. Results: Findings highlighted that, in one school, adolescents in denser and smaller friendship networks were at higher risk for engaging in sexual intercourse and drinking alcohol simultaneously. Additionally, in this school, network attributes (i.e., out-degree and betweeness) and adolescents’ age were associated with an increased risk of sexual intercourse and drinking behaviors. In the other school, more diffused friendship networks seemed to pose less risk of engaging in these two risk behaviors in tandem. Moreover, engagement in risky behaviors was significantly predicted by teens’ age and gender, but there were no effects of network attributes on adolescents’ risky behaviors. Conclusion: The influence of friendships on adolescents’ sexual intercourse and drinking alcohol may play out in different ways, depending on the size and composition of the friendship networks and adolescents’ characteristics. Therefore, structural features of friendship networks, such as denser and smaller networks, and characteristics of adolescents (i.e., age and gender) should be considered in developing intervention programs to reduce adolescents’ risky behaviors.