Associations between college enrollment and trends in substance use among young adults in the US from 2015 to 2019

<i>Background:</i> Substance use among college students has negative academic and health outcomes. Identifying substances that are more commonly used by students than non-students can reveal specific risks in the college environment.<i>Objectives:</i> To examine associations between college enrollment and prevalence and trends of use of a comprehensive list of substances.<i>Methods:</i> The sample included 2015-2019 participants in the National Survey on Drug Use and Health who were aged 18 to 22 and who were full-time enrolled or not enrolled in college. Prevalence of substance use was calculated for four subgroups: college males (<i>n</i> = 6,707), college females (<i>n</i> = 8,284), non-college males (<i>n</i> = 10,019), and non-college females (<i>n</i> = 9,266). Multivariate logistic regression was used to model the relationships between enrollment and substance use. Temporal trends in substance use prevalence were calculated for each subgroup.<i>Results:</i> College enrollment was associated with prescription stimulant misuse (aOR 1.50, 95% CI: 1.35-1.67), alcohol use (aOR 1.36, 95% CI: 1.27-1.47), and binge drinking (aOR 1.22, 95% CI: 1.15-1.30). From 2015 to 2019, the only substance whose use significantly increased among any subgroup was cannabis. The increase occurred among females only (+4.7% in college females and +5.6% in non-college females; both <i>p</i> < .01).<i>Conclusions:</i> College enrollment is most strongly associated with prescription stimulant misuse, suggesting that colleges should consider explicitly including stimulant misuse prevention in their health promotion strategies. The increasing use of cannabis among females warrants clinicians' attention to routine screening for use and provision of information about the mental health impacts of cannabis.