Project Summary/Abstract. Cumulative Adverse Childhood Experiences (ACEs) and childhood socioeconomic disadvantage (SED) have each been identified as major contributors to poor adolescent mental health and have been associated with one another. However, less is known about how cumulative ACEs and childhood SED operate together to influence adolescent mental health, resulting in disagreement among childhood adversity researchers. Without a clearer understanding of this complex relationship, we risk overlooking largely impactful social factors that influence adolescent health and well-being and our efforts to address the current youth mental health crisis will be hindered. The purpose of this Ruth L. Kirschstein National Research Service Award (NRSA) Individual Pre- Doctoral Fellowship in Nursing Research (F31) application is to prepare the applicant for a career as an independent investigator focused on expanding our collective knowledge of social risk factors and informing primary prevention strategies related to childhood adversity and adolescent mental health. The proposed fellowship consists of two complementary components: 1) a training plan aimed at developing the applicant’s methods proficiency, substantive expertise, and role attainment; and 2) a research project that will further our understanding of the relationship between childhood SED, ACE exposure, and adolescent depression and anxiety. A strong mentorship team that includes sponsors and collaborators from the University of Michigan’s Schools of Nursing, Public Health, and Social Work, as well as consultants from UM’s Poverty Solutions and School of Public Policy will provide interdisciplinary expertise in childhood adversity/trauma, child poverty, youth mental health, policy advocacy, intervention implementation, and advanced statistical techniques. The proposed research project will utilize data collected as part of the large, diverse, longitudinal Fragile Families and Child Wellbeing Study from birth through age 15. The specific aims are to: 1a) Investigate for the presence of distinct profiles of ACE exposure during early childhood and how childhood SED predicts profile membership; 1b) Examine the association between distinct ACE profiles and adolescent depression and anxiety, and if childhood SED moderates these associations; and 2) Investigate for transitions in ACE profile membership during early childhood, how childhood SED influences profile transitions, and how transitions are associated with mental health. Additional exploratory analyses will be conducted to assess the influence of additional social determinants of health, including race/ethnicity and biological sex. This study aligns with the NINR’s updated strategic plan by addressing health equity through the study of key social determinants of health and well-being. Findings from this study are critical for shaping future policy and research agendas, the allocation of scarce resources, and better identifying subpop...