Abstract
This post-registered study examined the daily associations between planned (versus unplanned) nicotine, cannabis, and alcohol use, and the moderating role of social normative factors (i.e., descriptive and injunctive norms, nicotine product exposure on social media) on these associations among sexual minority youth (SMY). Participants (N = 82) completed a baseline assessment then a 30-day ecological momentary assessment monitoring period. Plans to use substances early in the day were associated with greater later same-day substance use. Sexual minority friend descriptive norms were associated with greater unplanned nicotine use. Friend descriptive norms were associated with greater planned alcohol use. Friend descriptive norms moderated the associations between use plans and nicotine and alcohol use, and parental injunctive norms moderated the associations between use plans and nicotine use. These findings underscore behavioral intentions and social normative processes in substance use and suggest that tailoring interventions to address social norms may prove beneficial for SMY.