US Adult Illicit Cannabis Use, Cannabis Use Disorder, and Medical Marijuana Laws

Abstract

Over the last 20 years, laws and attitudes regarding cannabis have changed. As of November 2016, 28 states have passed medical marijuana laws (MML). Many adults now favor legalizing recreational use,¹ and fewer view cannabis as risky.² Despite this view, while some can use cannabis without harm,^3,4 potential consequences include impaired functioning,^3-7 vehicle crashes,^8-11 emergency department visits,¹² psychiatric symptoms,^13-16 and addiction.^3,17-19 Over time, the prevalence of adult illicit use and related consequences has increased.^{10,12,17,19-26} Thus, identifying factors underlying increased adult illicit use is important. State MML may be one such factor.¹⁸