PROJECT SUMMARY Early life adversity (ELA), such as physical or sexual abuse, witnessing a crime, family conflict, or community violence, can have prolonged effects and significantly increases the risk for later psychopathology. Experiencing such adversity can result in a wide range of psychiatric disorders, which have been found to be more resistant to treatment. Further complicating intervention efforts, some youth exposed to ELA continue to show normal functioning and behavior over time (“adaptive” or “resilient”), while others show increasing psychiatric symptoms and go on to develop psychiatric disorders (“vulnerable”). The factors and neurobiological mechanisms that underlie this variability and that prospectively identify those at greatest risk are not yet well understood. This is a critical knowledge gap in the ability to help youth who have experienced early life adversity. Recent research suggests that youth with ELA have abnormal function and connectivity within and between 3 core brain networks which support emotional reactivity and cognitive-emotional control - the salience network (SN), frontoparietal network (FPN), and default mode network (DMN), and changes in these networks are associated with a wide range of psychopathology. To date, however, no study has systematically examined the relative developmental trajectories of these core networks, how they are altered by ELA exposure, and how such alterations relate to the expression of general psychopathology risk and unique dimensions of internalizing vs. externalizing. The proposed study addresses these gaps of knowledge by examining the association between ELA, FPN, DMN, and SN network development, and both overall psychopathological load as well as specific dimensions of psychopathology using data from a large cohort (n=11,873) of adolescents from the Adolescent Brain Cognitive Development (ABCD) study. Demographic, environmental, and behavioral data are acquired every year and neuroimaging data are acquired every 2 years, starting at age 9-10y. This is a critical developmental period, the entrance into puberty, characterized by both a rapid emergence of psychiatric disorders as well as sex differences in the prevalence of internalizing and externalizing disorders. The function and interaction of SN, FPN, and DMN are examined both at rest and during cognitive load to determine the extent to which ELA-related network alterations are modality specific. Data are analyzed using both model-based and data-driven methods. Finally, this research uses both model- based prediction and machine learning to determine potential early predictors of later psychopathology.