PROJECT ABSTRACT Trauma is common and increases risk for a host of negative health outcomes, most notably posttraumatic stress disorder (PTSD). Given the potential harmful sequelae of trauma exposure, it is crucial to identify acute post-trauma risk factors that predict chronic PTSD. Moreover, urban racial/ethnic minorities can experience significant environmental stress that puts them at particularly high risk for PTSD. At this juncture relatively little data exists to aid in prediction of risk specific to urban racial minorities, or that takes into account how disadvantage and minority stress may impact neurobiological stress systems in the months following trauma, and how that affects risk for long-term distress. Thus, under the guidance of a community advisory board our team will 1) identify acute post-trauma neurobehavioral predictors of risk for chronic PTSD among urban Black Americans, with a focus on prefrontal-subcortical function during processing of threat, 2) characterize how the longitudinal interaction of socioenvironmental risk and resilience factors and biological stress markers following trauma impacts risk, and 3) use machine learning to identify the most robust set of predictors of chronic PTSD drawn from a comprehensive assessment of neuroimaging, biomarkers, self-report and geocoded risk and resilience variables. We will recruit 190 adults who identify as Black or African American from the Emergency Department at Froedtert Hospital/Medical College of Wisconsin in Milwaukee, and conduct comprehensive assessments at 2 weeks, and 3, 6, and 12 months following trauma exposure. The two-week and 12-month assessments will include measures of neural systems for threat processing, including both anticipation of and reactivity to threat. All visits will include measures of PTSD and other symptoms, neurobiological stress markers, particularly endocannabinoids, and socioenvironmental risk and resilience factors, especially those relevant for urban Black Americans. We will examine how acute post-trauma neurocircuitry variables (2 week) predict PTSD and other outcomes twelve months later, and how pre-trauma environmental variables (resource deprivation, child maltreatment, violence exposure) moderate this relationship (Aim 1). We will also assess how, in the months following trauma, socio-environmental risk and resilience factors influence neurobiological stress systems, and how this interaction impacts risk for PTSD, poor physical health, and emotion regulation neurocircuitry at twelve months (Aim 2). We will use both hypothesis-driven analyses focusing on a priori specified predictors (Aims 1 and 2), as well as comprehensive data-driven machine learning analyses (Aim 3). This approach will allow for determination of the additional utility of neurobiological markers for predicting risk beyond previously identified self-report indicators. We expect this project to lead to identification of predictors of PTSD following trauma for urban Blac...