Child maltreatment and interpersonal adversity put children at increased risk for posttraumatic stress disorder (PTSD), depression and suicide, substance abuse, and a host of negative mental health outcomes. Recent evidence documents that childhood adversity can have pernicious neurobiological and psychosocial effects that extend risk into adulthood. Trauma- Focused Cognitive-Behavioral Therapy (TF-CBT) has been demonstrated in numerous randomized clinical trials to be an efficacious treatment for maltreated and traumatized children. Early intervention with TF-CBT has the potential to alter the trajectory of risk associated with childhood adversity. The overall goals of the proposed research are to identify potential mechanisms of change, inhibitors of change, and predictors of early dropout in this treatment. The proposed research integrates a sophisticated analysis of the process of change into an ongoing effectiveness trial of TF-CBT that has been transported to community mental health facilities throughout the state of Delaware. Sessions from 75 children who received TF- CBT will be coded with an observational coding system designed to capture theoretically important therapeutic processes. TF-CBT is hypothesized to be associated with a curvilinear pattern of in-session affective arousal and cognitive/emotional processing of the trauma, with peak levels occurring when the child develops a trauma narrative in the exposure phase of therapy. A transient increase in affective arousal is thought to reflect activation of the trauma memories and to facilitate processing. More processing during this narrative phase is hypothesized to be the primary predictor of improvement in PTSD symptoms and problematic child behaviors. Therapist support and caregiver involvement in treatment are expected to help prepare the child for change by decreasing avoidance, a primary inhibitor of later arousal and processing. Caregiver avoidance and processing when exposed to the child's narrative are also expected to predict child outcomes. The proposed research has the potential to reveal key processes that can be mobilized to increase the potency of TF-CBT, reduce rates of dropout, and enhance therapist training as dissemination efforts are undertaken. PUBLIC HEALTH RELEVANCE: Child maltreatment and interpersonal trauma increase risk for a number of serious mental health disorders. Childhood adversity can be associated with pernicious neurobiological and psychosocial sequelae that extend risk into adulthood. Trauma- Focused Cognitive-Behavioral Therapy (TF-CBT) is an empirically-supported treatment that can alter this identifiable trajectory of risk. The goal of the proposed research is to identify key processes that inhibit and facilitate therapeutic change. Understanding how TF-CBT has its immediate and long-term effects can guide efforts to increase its potency, reduce dropout, and optimize therapy delivery.