Abstract
Emerging adults (ages 18-29) have the highest rates of both harmful drinking and participation on social network sites (SNSs) compared to adolescents and older adults. In fact, greater SNS participation has been shown to predict greater alcohol use. Little is known, however, about noncollege samples, substances apart from alcohol, and SNSs other than Facebook. Furthermore, few studies have examined what might moderate any observed influence of SNS participation on substance use. In this study, we used hierarchical linear and negative binomial regression analyses to examine the unique associations between Instagram participation and alcohol as well as marijuana use, controlling statistically for demographic characteristics, peer norms, and social status, in a community sample of emerging adults (N = 194). We also tested whether peer belonging or motives for Instagram participation moderated these relationships. Results showed that Instagram participation was positively related to alcohol use only for those with high levels of peer belonging. The initial negative association between Instagram participation and marijuana use disappeared once peer norms and social status were included. Peer norms were positively related to both alcohol and marijuana use, while peer belonging was positively related to marijuana use. Peer belonging appears to be an important variable in the study of SNSs and substance use among emerging adults. Future work might test the somewhat counterintuitive hypotheses raised by these findings that peer belonging sensitizes individuals to SNS influences on drinking and could be a marker of greater marijuana use.