Abstract
OBJECTIVE: To determine if social enhancement outcome expectancies, harm perceptions, and social normative beliefs, explain why young adults with a greater amount of peers who use electronic nicotine delivery systems (ENDS) subsequently report past 30-day ENDS use two years later. METHOD: Participants were 1,721 young adults, who had used ENDS at least once, in the final three annual waves of a longitudinal study (spring 2017, 2018, 2019). At baseline, participants were 20-25 years old (M = 22.7; SD = 1.4), 64.0% female; 20.7% identified as a sexual gender minority; 33.7% non-Hispanic white, 34.3% Hispanic/Latino, 16.7% Asian, 7.4% Black, and 8.4% two or more or another racial/ethnic identity. A mediation model was used to test the study hypothesis. The exogenous predictor, peer ENDS use, was assessed at baseline. The mediating variables, social enhancement outcome expectancies, harm perceptions, and social normative beliefs (perceived social acceptability and willingness to date someone who uses ENDS) were assessed one year later. The outcome variable, past 30-day ENDS use, was assessed two years after baseline. Covariates included socio-demographic characteristics, past 30-day use of ENDS, tobacco, and cannabis, and past 14-day binge drinking, all assessed at baseline. RESULTS: Only the social normative belief of a greater willingness to date someone who uses ENDS significantly mediated the peer ENDS use - past 30-day ENDS use association two years later (b = 0.04, SE = 0.012, Bootstrap 95%CI: [0.02, 0.07]). CONCLUSIONS: Prevention and intervention programs should consider altering favorable social normative attitudes toward ENDS into less favorable ones to decrease ENDS use in young adulthood.