My friends made me do it: Peer influences and different types of vaping in adolescence.

Vaping is one of the most common forms of substance use among adolescents. Social influences play a key role in the decision to use substances and frequency of use during adolescence, and vaping is no exception. Using a sample of 891 adolescents across two time points (M = 15.1 and M = 17.2) in this pre-registered study, we explored whether the frequency of vaping nicotine and the frequency of vaping marijuana at age 17 were related to concurrent reports of resistance to peer influence (RPI), perceptions of friends vaping, and perceptions of classmates vaping. Then, we investigated whether resistance to peer influence reported at age 15 was similarly related to age 17 vaping of both substances. Higher RPI at both ages 15 and 17 was associated with a higher probability of abstaining from vaping both substances but was not related to the frequency of vaping among those who vaped. Perceiving that a higher proportion of friends - but not classmates - vaped was associated with a lower probability of abstaining and a greater frequency of vaping among those who vape (for both substances). Higher RPI had an attenuating effect on the relation between perceptions of vaping among peers and an adolescent's own vaping behavior, but that differed by age and peer group (e.g., friends vs. classmates). Overestimation about the prevalence of classmate vaping may have played a role in the findings, but our results suggest that interventions to strengthen peer resistance across adolescence are warranted.