PROJECT SUMMARY/ABSTRACT American Indian/Alaska Native (AI/ANs) individuals experience some of the highest rates of co-occurring mental health and substance use problems in the United States. These disparities reflect broader systemic and community level inequities among urban-dwelling AI/AN individuals. Systemic factors, such as poverty, unemployment, and discrimination are underlying barriers to accessing healthcare and substance use treatment, affecting nearly a quarter of AI/AN people. Emerging adulthood (ages 18-25) is a developmental period often characterized by instability, role transition, and self-exploration. Some evidence suggests that AI/AN emerging adults often experience this key formative life stage while coping with discrimination, social and economic inequities, and rapid cultural change, which all can affect mental health and substance use. However, little is known about risk and protective factors among urban AI/AN emerging adults that may be associated with health inequities. The aims of this supplement are within the scope of the parent grant; however, they substantially expand the parent project by allowing us to analyze our survey baseline data in new ways, as well as combine these survey data with new qualitative data: Aim 1- utilize baseline survey data (n=125) to examine how risk factors (e.g., discrimination, historical loss), and protective factors-- cultural identity and connection (e.g., cultural connection, cultural identity, and participation in traditional practices), and social support (e.g., emotional, tangible, and support from rural or urban network contacts) are associated with opioid, alcohol and cannabis use and mental health outcomes; and Aim 2- conduct in-depth interviews with a subsample of 20 participants recruited from the baseline sample who report different types of experiences (e.g., high rates of discrimination/loss, high rates of cultural engagement, social networks with rural support, social networks with urban support) to better understand urban AI/AN emerging adults? experiences with discrimination and historical loss, cultural identity and connection, and social support. Findings will support the parent grant by providing new information on how to best address health equity among urban AI/AN emerging adults, given the different risk and protective factors that they experience in their lives. Findings can help build an empirical, culturally grounded rationale for how to enhance opioid and AOD prevention intervention services to ensure equity for this population. This will be the first study to date to take a mixed methods approach to understand specific structural drivers of inequity as well as key protective factors for AOD use and mental health among urban AI/AN emerging adults. Findings can move the field forward in this understudied area by highlighting how providers and policy makers can better address the inequities that AI/AN emerging adults experience.