Research indicates that youths are particularly susceptible to peer influence and that identifying with substance using peer groups predicts substance use. Today, youth spend more time interacting with distal peer groups via the Internet and have increased access to online drug cultures. Theoretically, this should have important implications for substance use. This study employs a nationally representative sample of U.S. youth (n = 1212), ages 15-25 years old, to examine whether online peer group identification and social media homophily predict substance use. Results indicate that online belonging and social media homophily are associated with some forms of substance use. While these factors were not significantly associated with regular marijuana or alcohol use among those who had initiated use, they predicted regular stimulant and opioid use among substance users. This suggests that online peer groups may promote progression into more problematic forms of substance use. Additional analyses of adolescent and young adult subgroups revealed important similarities and differences among the groups. The findings imply several directions for future research, and suggest that prevention policies and programs should continue to consider the role of online peers, and the Internet generally, in substance use initiation, escalation, and prevention.
Keywords: Social media; drugs; peers; substance use; young people.