LAUSR

This research focuses on associations of medical marijuana legalization with prescription drug misuse, illicit drug use, and a combination of both behaviors. Using three waves of the National Survey of Drug Use and Health (NSDUH, 2016–2018), adult participants (age ≥ 18) were selected for the final study sample (n = 127,438). Multinomial logistic regression was adjusted for biological, socioeconomic, and substance use measurements. Results from multinomial regression demonstrated that medical marijuana legalization was positively associated with illicit drug use (relative risk ratio [RRR] = 1.33, 95% confidence interval [CI] = [1.17, 1.51]; p < .01) and both prescription drug misuse and illicit drug use (RRR = 1.14, 95% CI = [1.05, 1.25]; p < .01) among U.S. adults. It is recommended to design policy interventions to counter illicit drug use and a combination of both prescription drug misuse and illicit drug use as the result of medical marijuana legalization.