PROJECT SUMMARY Recent estimates suggest one in four children under age 18 have a behavioral health (BH) diagnosis such as anxiety or depression. Limited health insurance coverage, a paucity of BH providers, and stigma associated with BH disorders result in less than half of children receiving evidence-based treatment. Children with a high number of adverse childhood experiences, lower socio-economic status, and who are members of minoritized populations, including sexual and gender minority (SGM) youth, have a higher risk for BH disorders and disparate healthcare. SGM youth have higher risk of self-injurious thoughts and behaviors compared to their non-SGM peers. Accountable care organizations (ACOs) incentivize care integration and population health, which promotes care coordination, linkages to community-based services, and development of interventions to address social determinants of health. Despite widespread use of ACOs in state Medicaid programs (12 states in 2021) and the potential for innovative reforms introduced by ACOs to improve BH care for children in vulnerable populations, little is known about ACOs’ impact on pediatric BH care. Our parent grant (NIMH R01MH134176) aims to identify the impacts of ACOs on BH care quality, outcomes, and experience, including identifying heterogeneity of effects among ACOs with different organizational features. This administrative supplement will allow us to enhance our ongoing research with additional information about the role of Medicaid ACOs in care for SGM youth and whether organizational differences in ACOs contribute to patient experience for Medicaid insured SGM youth with BH disorders. In response to Notice of Special Interest (NOSI) NOT-OD-22-032, we propose to enhance our parent grant by (enhanced Aim 2) describing ACOs’ organizational approaches to care for SGM youth and (enhanced Aim 3) inclusion of SGM youth experience with BH care in the assessment of the association of Medicaid ACO organizational features with parent/patient experience through targeted sampling to achieve an adequate sample size. This proposed supplement is responsive to the NOSI as our parent grant is examining access to health-related services and associated barriers among children with BH disorders, and this supplement will allow us to enhance our existing aims with additional data collection on ACO approaches to care for SGM populations and the addition of SGM youth participants. The timing is ideal to complete the study within 12 months given our study team’s recent experience with studies focusing on SGM youth populations and overlap with planned timing of parent grant data collection activities. The proposed research is important due to ongoing inequities in access and outcomes, including suicide, between SGM and non-SGM youth. This study will provide important insights about whether Medicaid ACOs are addressing disproportionate burdens among SGM youth and inform future studies on the role of delivery and fina...