PROJECT SUMMARY/ABSTRACT Latinx adolescents experience higher rates of behavioral health risks compared to their non-Latinx Black and White peers, particularly for marijuana, alcohol, and cocaine use, depression, and suicidality. Poor mental health and substance use have been attributed to experiences of adversity, stress, and perceived interpersonal discrimination. Advances in the field of Latinx youth mental health research has been largely focused on individual and interpersonal determinants. Few studies examine the impact of social and environmental contexts, such as those related to immigration status, on Latinx youth mental health. Laws and policies at federal, state, and local levels, or the absence of such laws, also affect Latinx immigrant stress and access to resources, increasing mental health risk for Latinx adolescents. These policies shape anti-immigrant environments and prejudice toward Latinx youth, amplifying experiences of stress and mental health issues. Inclusive immigration policies increase access to health and social resources. Research examining pathways between state and local and the mental health of Latinx youth is needed. The proposed study will fill gaps by applying a transdisciplinary approach to understand and intervene a health disparity and equity issue. The objectives of this research are to: (1) construct a state-level dataset on interrelated policies that structure access for Latinx youth; (2) use quasi-experimental methods to quantitatively estimate the effects of state-level policies on Latinx youth mental health and qualitatively explore how policies shape the social lives of Latinx youth; and (3) develop community-informed recommendations for prevention and intervention solutions. With a focus on interdisciplinary collaboration, Temple University offers early career scholars the intellectual and practical resources to develop into successful independent investigators. The overarching training plan for this K01 application serves to consider the effects of macrolevel policies that either promote health or produce inequities related to mental health. The training plan is designed to develop the candidate’s skills in public health law research and legal epidemiology, quasi-experimental design methods and community-engaged research to develop ground-level recommendations for prevention and intervention. By engaging in coursework, trainings, applied experiences, and national conferences, complemented by a transdisciplinary team of mentors from law, public health, health behavior and translational research fields, Dr. Villamil Grest’s training and career development plan provides an opportunity to advance her interdisciplinary skills to understand the upstream, structural level factors that affect the health and well-being of Latinx youth. To achieve success as an independent scholar and researcher, this K01 will provide skills for the PI to become a multimethod investigator, examining the social and structural f...