Associations between social network characteristics and alcohol use alone or in combination with cannabis use in first-year college students.

OBJECTIVE Simultaneous use of alcohol and cannabis is common among young adults, but little research has examined social ties and their relation to simultaneous use. This study investigated the social network characteristics of college students at two time points in the first year of college. Participants were categorized into those who used alcohol and cannabis, such that their effects overlap (simultaneous users), those who used both substances without overlapping effects (concurrent users), and those who used alcohol only. METHOD First-year college students (N = 1,294) completed online questionnaires during the fall and spring semester. At both assessments, participants nominated up to 10 important peers in their class, reported on peers' alcohol and cannabis use, and reported their own use of alcohol or cannabis with each peer. RESULTS Concurrent and simultaneous users reported a greater proportion of drinking buddies than those who used alcohol only. A greater proportion of friends who used alcohol or cannabis, but not the proportion who were "drinking buddies" or "cannabis buddies," was associated with increased odds of simultaneous use relative to concurrent use. Participants nominated network ties that paralleled their own substance use (e.g., the majority of simultaneous users' networks ties were also simultaneous users). CONCLUSION Having a larger percentage of friends who use cannabis and alcohol is associated with increased odds of using both substances at the same time, perhaps because it gives access to both substances at the same time. Interventions should account for amount of exposure to alcohol and cannabis use from network members. (PsycInfo Database Record (c) 2021 APA, all rights reserved).