PROJECT SUMMARY/ABSTRACT In response to RFA-MH-20-521, this R34 application proposes to adapt a stigma-reduction training, develop a new prescribing platform, and pilot test these implementation strategies to improve the integration of pharmacotherapy for serious mental health disorders and alcohol use disorder (AUD) in Ryan White care sites in three counties of the Ending the Epidemic Plan—Dekalb, Gwinnett, and Cobb Counties in the Atlanta Metro area. We propose to engage a Community Collaborative Board (CCB) that includes people living with HIV (PLHIV) and conduct in-depth interviews with PLHIV to adapt the Health Policy Project's stigma-reduction training to address mental health and substance abuse-related stigma. We also will engage an expert panel of psychiatrists and experts in HIV medicine and conduct focus group discussions with providers to inform the development of the You℞ Decision prescribing platform, which will help providers make decisions about prescribing medications for depression, PTSD, bipolar disorder, and AUD among PLHIV. This platform will be accessible via mobile devices— smartphones and tablets—and will use algorithms based on best practices in HIV primary care and refined based on feedback from experts in HIV medicine and psychiatry to guide HIV providers in developing the best medication regimens for patients with comorbid disorders. For this planning grant, we will use the Consolidated Framework for Implementation Research, the ERIC recommendations, and Proctor's implementation taxonomy to explore the determinants of implementation, identify implementation strategies, and assess the acceptability of the stigma-reduction training and assess feasibility and acceptability of the You℞ Decision prescribing platform in Positive Impact Health Centers, which are Ryan White-funded care sites. We will also conduct a pilot trial to assess the preliminary impact of the stigma-reduction training to reduce clinic-level stigma and the You℞ Decision prescribing platform to increase providers' self-efficacy related to prescribing psychiatric medication and naltrexone (targeted mechanisms) and their provision of pharmacotherapy for depression, PTSD, bipolar disorder, and AUD (adoption). Specific Aims: Aim 1: To conduct formative activities with PLHIV, HIV care providers, and our CCB to adapt a stigma-reduction training to address mental health and substance abuse-related stigma among clinic staff and engage HIV care providers and an expert panel to develop the You℞ Decision prescribing platform to support HIV care providers to offer pharmacotherapy to treat depression, PTSD, bipolar disorder, and AUD. Aim 2: To assess the acceptability of the stigma-reduction training among clinic staff and the feasibility, acceptability, and adoption of using the You℞ Decision prescribing platform during clinical encounters among providers in HIV care settings. Aim 3: To use idiographic methods to conduct a pilot trial to assess the preliminary impact...