RecruitingEarly Phase 1Drug trialCannabidiol in Opioid Use Disorder and Chronic PainThis is a randomized, placebo-controlled, crossover human laboratory study investigating the dose-dependent safety and acute effects of Cannabidiol (CBD) on measures of pain and opioid craving in outpatients with opioid use disorder (OUD) receiving medication-assisted treatment with methadone or buprenorphine. With a duration of approximately 4 weeks, participants will come to the testing site for a total of five times: one initial screening session, and four experimental sessions where study medication, CBD, will be administered, separated by at least 72 hours to limit carryover effects.