PROJECT SUMMARY In 2020 there was an estimated 20% increase in opioid overdose deaths from the previous year, and Black/African American communities are experiencing drastic increases in opioid-related fatalities. Medication for opioid use disorder, including methadone maintenance treatment (MMT), has a long history of efficacy for treating opioid use disorder (OUD), but retention is a persistent challenge. Racial/ethnic minority individuals with OUD disproportionately evidence poor outcomes, including worse MMT retention. There is an urgent need to better understand barriers to MMT retention in order to inform targeted and efficient interventions, especially among Black/African American individuals with OUD. Stigma at multiple levels, surrounding both substance use disorder (SUD) and MMT, is a key driver of poor MMT outcomes, social devaluation, and inequality. Within the level of “self,” stigma can be further categorized based on how individuals respond to and process stigma. Internalized stigma refers to stigma directed at the self from the self. Anticipated stigma (expectation to be the target of discrimination) and enacted stigma (past lived experience of discrimination) reflect stigma directed at the self from others (family, employer, health care provider, etc). Further, racial minority individuals with OUD also routinely experience race/ethnicity-related stigma and discrimination in everyday social situations, which has been found to be broadly associated with poor mental and physical health outcomes, and may further worsen OUD outcomes. Research quantitatively evaluating the intersection of racial discrimination, SUD and MMT stigma is surprising sparse, and rarely tested in relation to MMT outcomes. The proposed study builds on our team’s formative qualitative work, led by this proposal’s PI (Kleinman), which describes the pervasive experience of SUD and MMT stigma and racial discrimination among people in MMT at a community-based program in Baltimore City, which has one of the highest overdose-fatality rates in the country and greatest burdens of OUD among low-income, racial/ethnic minority individuals. In the proposed study, we will evaluate the experience of racial discrimination as well as internalized, anticipated, and enacted SUD and MMT stigma in a population of patients starting MMT who identify as Black/African American (N=180). We will then prospectively examine the effects of stigma and racial discrimination on subsequent MMT retention at 90 days after treatment initiation. Finally, we will utilize moderation models to evaluate interactive effects between racial discrimination and stigma measures on MMT retention. Results of this study have the potential to inform theory and data driven interventions to improve MMT adherence and retention, particularly for this underserved and disproportionately affected population. This study will serve as an important bridge for the PI (Kleinman) from her graduate training to her promising e...