Emerging Adults' Public and Private Discussions of Substance Use on Social Media

Substance use increases during emerging adulthood and may relate to higher concurrent and future problems. For a community sample of 140 emerging adults, this study explores the associations between reported alcohol, marijuana, and tobacco use in 12th grade, the content of public posts and private messaging on Facebook during the fall after 12th grade, and self-reported substance use 1 year after high school. About one quarter of participants discussed substances publicly, and nearly half discussed substances privately on Facebook as observationally coded by researchers. Twelfth-grade substance use predicted the probability of engaging in public and private substance-related discussions. Tobacco and marijuana use predicted the frequency of private messaging about substances. Public and private online substance discussions predicted positive changes in marijuana use 1 year later. Results from this study suggest that social media discussions about substances, particularly private messages, may signal and shape emerging adults' substance use behaviors.