Researchers have recently analysed state registry data to provide nationwide estimates to elucidate the qualifying conditions for which patients are licensed to use cannabis medically. The research also compared the prevalence of medical cannabis qualifying conditions to recent evidence from the National Academies of Sciences, Engineering, and Medicine report on cannabis’s efficacy in treating each condition. 20 US states and the District of Columbia had available registry data on patient numbers, and 15 had data on patient-reported qualifying conditions. Chronic pain is currently and historically the most common qualifying condition reported by medical cannabis patients (64.9 percent in 2016), followed by use for complications of multiple sclerosis. Of all patient-reported qualifying conditions, 85.5 percent had either substantial or conclusive evidence of therapeutic efficacy.