PROJECT SUMMARY Violence and humanitarian crises are common in the lives of children around the world, particularly in low- and middle-income countries. Exposure to war-related violence is detrimental to the mental health of parents and children, but research exploring mechanisms by which emotional and behavioral disruptions are transmitted to subsequent generations remains nascent, especially in Sub-Saharan Africa. To help address this gap, a study of war-affected youth has been underway since 2002 following a cohort of war-affected children—many, both male and female, former child soldiers—in Sierra Leone into young adulthood, and now parenthood. A prior NICHD-funded R01 (R01HD073349) demonstrated how childhood war-related trauma and loss contributed to mental health problems in adulthood. In 2017, a cross-sectional sample of intimate partners and biological offspring was added to the sample to examine linkages between early trauma exposure and both intimate partner and parent-child relationships. Knowledge to date of how war-related stressors “get under the skin,” to become heritable biophysical traits and the implications for the mental health of the next generation remain limited. Of relevance are the Research Domain Criteria-related constructs of self-regulation and stress reactivity and how they influence emotional, cognitive and social functioning of children. The proposed research comprises a significant advance in the 20-year history of this study by advancing understanding of potential biological embedding of stress responses intergenerationally. Building on four prior waves of data collection, biological measures of stress reactivity and self-regulation (autonomic nervous system reactivity, inflammation, telomere length) will be collected in a sample of parents exposed to significant trauma in childhood and extended also to intimate partners and offspring. Strong capacity-building collaborations with Sierra Leone’s University of Makeni (UNIMAK) and Kenema Government Hospital (KGH) will support the ethical collection of new stress biomarker data and clinical assessments of parent-child synchrony, health, and anthropometric data in biological offspring aged 7–24. Key study innovations are (a) rare prospective data on parental trauma exposure and longitudinal information on risk and protective factors operating across the social ecology; (b) data on biological embedding of stress responses related to parental trauma; and (c) the opportunity to examine both mental health and physiological outcomes in biological offspring in war-affected families over time. Advanced statistical techniques (e.g., latent class growth models, structural equation models, lagged effects models) will articulate mechanistic pathways and priority targets for intervention. Collaborations between investigators, UNIMAK, KGH, as well as community advisory boards will inform study implementation, ensure strong retention of participants, and provide channels for dissemi...