Improving Sleep and Emotional Well-Being in Adolescents with Early Life Adversity: A Transdiagnostic Sleep and Circadian Intervention - PROJECT SUMMARY/ABSTRACT Early Life Adversity (ELA), including maltreatment and parental separation, is a significant public health issue, with nearly two-thirds of individuals experiencing at least one adverse event before age 18. Adolescents exposed to ELA are at increased risk for mental health disorders, including depression, anxiety, and post- traumatic stress disorder (PTSD). Sleep and circadian disturbances, such as insufficient sleep, social jetlag, poor sleep quality, and low sleep efficiency, are common among these adolescents and may further exacerbate their mental health challenges. Sleep disturbances may also contribute to systemic inflammation, as indicated by elevated levels of C-reactive protein (CRP), which is associated with mental health problems. This R34 project will adapt and pilot test the Transdiagnostic Sleep and Circadian Intervention (TranS-C) for adolescents aged 14-17 who have been exposed to ELA and experience sleep disturbances. In collaboration with the Olive View Clinic, a pediatric clinic serving adolescents with ELA (i.e., child welfare-involved youth), we will adapt TranS-C to ensure it is trauma-informed and meets the unique needs of this population. Aim 1 will involve adapting the intervention using focus groups with adolescents, parents, and behavioral health providers, along with usability testing among ELA-exposed adolescents with sleep disturbances (n = 5) to refine the intervention before the pilot randomized controlled trial (RCT) in Aim 2. Aim 2 will pilot an RCT with 60 adolescents, comparing the adapted TranS-C to a delayed treatment control. Primary outcomes include sleep duration, social jetlag, and depression. Secondary outcomes include sleep quality, sleep efficiency, sleep timing, daytime alertness, anxiety, PTSD symptoms, and daily affect (negative and positive affect). Exploratory outcomes will assess the feasibility of collecting salivary CRP as a marker of systemic inflammation. This study will inform the feasibility of a trauma-informed sleep intervention for adolescents exposed to ELA in a real- world clinic setting, laying the foundation for a future, adequately powered trial of a scalable and culturally- adapted intervention as well as a better mechanistic understanding of the sleep-inflammation-mental health nexus.