PROJECT SUMMARY Access to mental health specialists is limited for many patients in the U.S., particularly for those who live in rural or other underserved communities. Telemental health is one potential solution for this access problem. Prior to the COVID-19 pandemic, use of telemental health was growing in rural communities, but overall use was still low. During the public health emergency (PHE), use of telemental health increased dramatically across the U.S., and telemedicine currently accounts for the majority of mental health visits. Now that most clinicians and patients in treatment have tried telemental health, it is unclear how they will choose to incorporate this technology into clinical care after the PHE ends. In this renewal we seek to understand the future role of telemental health in mental health treatment and its relationship to access, equity, and quality of care. In the first four years of our mixed-method R01, we made substantial progress in understanding how telemental health is being used in real-world settings. We described its growth, how use varied substantially across communities, and whether it had reduced urban-rural disparities in care pre-COVID-19. In the last year, we pivoted to understanding the role that telemental health has played during the PHE and we worked directly with health plans, state government, and the federal government to inform policy decisions. Building off this foundation, we seek a renewal of our RO1 to understand how use of telemental health changes mental health practice after the PHE ends and the association of these new practice models and quality of care. Under the first aim, we seek to inform ongoing policy debates on reimbursement, licensure, and regulations by measuring differences in telemental health use in response to post-PHE changes in regulation and reimbursement. There has been considerable debate on whether telemental health will increase or decrease disparities in care. In the second aim, using both quantitative and qualitative analyses, we will assess the role of telemental health in care for disadvantaged populations and what is being done to address disparities. Under the third aim, we will explore how telemedicine has changed how clinicians treat major depression and bipolar-I disorder, illnesses representing different (on average) severity and chronicity, and, in the fourth aim, whether different telemental health patterns are associated with improved or worse outcomes. We will use a mixed methods approach that incorporates into each aim both quantitative analyses of Medicare, Medicaid, and commercial insurance claims data and qualitative interviews (either of providers or patients). Understanding how telemental health is incorporated into mental health treatment after the PHE, whether its use worsens or narrows existing disparities in care, the role of regulation and reimbursement in telemental health use, and whether different patterns of use are associated with higher qual...