Parent Grant Project Summary Substance use (SU) rates among American Indian (AI) adolescents have been greater than national rates for decades, and recent evidence indicates that some SU disparities are increasing for AI adolescents living on or near reservations (hereafter reservation). Given the changing nature of SU and the unique influences on this population (e.g., factors specific to reservation life), continued surveillance and dissemination of SU rates for these youth is vitally important to inform prevention, treatment, and policy efforts. The proposed study is a renewal of a large-scale epidemiological study of SU among reservation AI adolescents, the only study of its kind. Each year, nationally-representative rates of SU for reservation AI adolescents will be obtained and compared with national rates measured by Monitoring the Future (MTF) in order to identify areas of special concern for reservation AI adolescents. The sample will be expanded to include 6th graders due to early initiation rates of AI youth. The study will move beyond basic epidemiology to include additional analyses of low-base rate/high-risk SU (e.g., methamphetamine, opioids) and heavy marijuana use, examining simultaneous and co-occurring use, predictors of use, and consequences of use. Because data are gathered from a wide variety of contexts (e.g., reservations), a comprehensive multilevel analysis examining relationships of school/community factors will be conducted, building on epidemiologic models. The findings from these analyses will provide essential information for reducing health disparities that result from structural and economic inequities, policy, and allocation of resources. Building etiologic evidence for effective intervention to address high rates of adolescent AI SU is also a fundamental part of this project. Although AI adolescents are influenced by broader society, unique individual, cultural, geographic, economic, and other factors influence SU and its correlates and consequences. Moreover, there has been limited focus on understanding how positive characteristics related to strength and resilience serve as protective or promotive factors for AI adolescents. Etiologic models, based on eco-systemic resilience theory, will be used to assess the role of individual, cultural and collective measures of strength and resilience to identify relationships to SU and delayed or nonuse. Measures of low-base rate/high-risk and heavy marijuana use will be included as dependent variables in these analyses. An ongoing discussion among AI researchers is the need for systematic analysis of the role of racial-ethnic and cultural identity in SU behaviors; therefore, this study will give special emphasis to assessing psychometric properties of measures of racial/ethnic identity that have been used successfully for prediction in this and other populations. Project findings will be disseminated to key stakeholders, with special emphasis on tribal and non-tribal...