RecruitingImpact of Federal and State Medications for Opioid Use Disorder (MOUD) Policy Changes During the Pandemic"Gold-standard" medications for opioid use disorder (MOUD) treatment combines FDA-approved medications, primarily methadone and buprenorphine, with behavioral therapies to provide "whole-patient" treatment. Prior to the pandemic, methadone and buprenorphine were subject to greater federal regulations than medications for other substance use disorders, including medication for alcohol use disorder (MAUD), which created barriers to MOUD initiation and retention. These barriers were exacerbated by physical distancing and diminished clinic capacities during the COVID-19 pandemic. To prevent healthcare disruption and expand access to MOUD treatment during the public health emergency, federal and state authorities implemented several MOUD policy changes during the pandemic to reduce barriers to MOUD initiation and retention, which subsequently became permanent. This study is an evaluation of the impacts of these policies on treatment use, retention, and patient outcomes pre- and post-MOUD policy implementation.