Marijuana, but not alcohol, use frequency associated with greater loneliness, psychological distress, and less flourishing among young adults

•Young adult substance use and social and emotional health indicators were assessed.•Marijuana use was associated with loneliness and distress and less flourishing.•Alcohol use frequency was not associated with any of the indicators of well-being.•Frequent marijuana users may show low levels of social and emotional well-being. To assess whether frequency of marijuana and alcohol use are cross-sectionally associated with indicators of social and emotional well-being including loneliness, psychological distress, and flourishing across important life domains among young adults. The study sample included 562 participants ages 22–29 who were originally recruited from an urban Pacific Northwest region in the US as part of a longitudinal study of social role transitions and alcohol use. At one assessment, participants completed an online survey that included a 3-item measure of loneliness, a 4-item measure of depression and anxiety symptoms, and a 12-item measure of flourishing as well as measures of marijuana and alcohol use frequency. Linear and generalized linear models were used to estimate associations of marijuana and alcohol use frequency with indicators of well-being. Greater frequency of marijuana use was associated with higher levels of loneliness, higher levels of psychological distress, and lower levels of flourishing, with the greatest difference observed for daily marijuana users compared to non-users. However, these indicators of well-being did not significantly differ by levels of alcohol use frequency. Study findings suggest that frequent users of marijuana, but not alcohol, may experience more loneliness, more psychological distress, and less flourishing. Intervention approaches for frequent marijuana users may be warranted to reduce impacts of loneliness and psychological distress and improve overall well-being.