Association Between Social Media Use and Substance Use Among Middle and High School-Aged Youth.

: The purpose of our study was to identify whether different aspects of social media use were associated with substance use among middle- and high school-aged youth. : Participants were recruited from four Northeast U.S. middle schools and invited to complete an online survey in Fall 2019 and Fall 2020. We conducted separate adjusted logistic mixed effects models the substance use outcomes: ever use of alcohol, cannabis, e-cigarettes, tobacco cigarettes, prescription drugs, and multiple substances. Our sample included  = 586 participants (52.7% female, 58% White). : Seeing a social media post about drugs/alcohol in the past-12-months was significantly associated with higher odds of ever using alcohol, cannabis, e-cigarettes, and multiple substance use. Total number of social media sites ever used was significantly associated with higher odds of ever using cannabis, cigarettes, e-cigarettes, and multiple substances. Checking social media every hour or more was significantly associated with higher odds of ever using alcohol. Higher problematic internet use score was significantly associated with higher odds of ever using cannabis, e-cigarettes, and multiple substances. Online social support seeking score was not associated substance use. : Our findings support the need for substance use prevention and social media literacy education and screening to begin early, ideally in elementary school before youth are using social media and substances.