Until this study, little was known about changes in cannabis use outcomes by race or ethnicity following passage of recreational cannabis laws among states that already had passed medical cannabis use laws (all states that passed recreational laws had already passed medical laws in earlier years)," said Silvia Martins, MD, Ph.D., associate professor of epidemiology at Columbia Mailman School, and first author. "Furthermore, as one of the stated goals of cannabis legalization is to combat racial inequalities in cannabis legislation enforcement, it is critical to examine patterns of use in the context of persistent racial and ethnic disparities in cannabis arrests and incarceration." By January 2021, 15 states and Washington, D.C. had fully legalized cannabis use for adults over 21 and an additional 21 states had legalized medical cannabis. Using data from the 2008-2017 National Surveys of Drug Use and Health, between September 2019 and March 2020 for those 12 years of age...