Mediating Factors That Explain the Link Between Exposure to Alcohol Content on Social Media and Alcohol Use: A Systematic Review and Meta-Analysis.

Despite evidence that there is a link between exposure to alcohol-related content on social media and alcohol use, there has been less focus on testing the underlying mechanisms that explain the link. Findings from the primary studies that test the mechanisms are fragmented and inconsistent, with no systematic synthesis to date. We aimed to identify what mediators had been tested that may explain the link between exposure to alcohol-related content on social media with alcohol use. We conducted a systematic search of five major databases (MEDLINE, PsycINFO, CINAHL, Web of Science, and ProQuest). Article selection and data extraction were performed independently by at least two reviewers. The pooled indirect effect of social media alcohol exposure via the selected mediators was estimated using a two-stage meta-analytic structural equation modeling approach. Of the 397 articles screened, 10 studies met the inclusion criteria. Overall, social norms were the most common mediator examined. Our meta-analysis found significant indirect associations between social media alcohol exposure and alcohol use via descriptive norms (B = 0.07; 95% CI: 0.05-0.10) and injunctive norms (B = 0.05; 95% CI: 0.02-0.07). Other mediators identified included drinking motives, alcohol-related beliefs (e.g., "drinking makes socialising easier"), drinking identity, and poster prototypes (i.e., perceptions of the typical people who post alcohol-related content). Exposure to alcohol-related content on social media was indirectly associated with alcohol use through psychosocial factors, mainly perceived social norms. Norms-focused strategies (e.g., personalized normative feedback) may be a useful component of multi-component interventions, alongside approaches targeting other pathways.