Introduction: The current study applied egocentric social network analysis (SNA) to investigate the prevalence of
addictive behavior and co-occurring substance use in college students' networks. Specifically, we examined individuals'
perceptions of the frequency of network members' co-occurring addictive behavior and investigated
whether co-occurring addictive behavior is spread evenly throughout networks or is more localized in clusters.
We also examined differences in network composition between individuals with varying levels of alcohol use.
Method: The study utilized an egocentric SNA approach in which respondents (“egos”) enumerated 30 of their
closest friends, family members, co-workers, and significant others (“alters”) and the relations among alters
listed. Participants were 281 undergraduates at a large university in the Southeastern United States.
Results: Robust associations were observed among the frequencies of gambling, smoking, drinking, and using
marijuana by network members. We also found that alters tended to cluster together into two distinct groups:
one cluster moderate-to-high on co-occurring addictive behavior and the other low on co-occurring addictive behavior.
Lastly, significant differences were present when examining egos' perceptions of alters' substance use between
the networks of at-risk, light, and nondrinkers.
Conclusions: These findings provide empirical evidence of distinct clustering of addictive behavior among young
adults and suggest the promise of social network-based interventions for this cohort