Mild traumatic brain injuries (mTBI) were commonly sustained among those who served in Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND) and are associated with increased rates of mental health disorders, including posttraumatic stress disorder (PTSD). Indeed, among a cohort of those who served in the conflicts and sought Veterans Health Administration care, 89% of Veterans with a mTBI had a comorbid psychiatric disorder, with PTSD being the most common (73%). Unfortunately, symptom overlap between mTBI and mental health conditions can impact diagnostic clarity and prognosis. This can hamper implementation of personalized approaches (i.e., precision medicine) focused on enhancing assessment and treatment to ensure brain health and associated optimal psychosocial functioning. Moreover, such personalized care strategies would also be expected to decrease risk for negative outcomes like suicide. Based on increased risk for suicide among both younger and older cohorts of Veterans, suicide prevention remains the highest clinical priority within the VHA. One solution to overcoming existing data and clinical challenges is the integration of existing data sets focused on both clinical outcomes (e.g., PTSD symptom severity) and physiologic biosignals/functional measures (e.g., electroencephalogram [EEG] activity, computerized posturography, computerized eye tracking). Such an approach would allow the application of advanced analytic techniques to develop algorithms (e.g., diagnostic, prognostic) that can be used to promote brain health among Veterans with co-occurring mTBI and mental health sequelae (e.g., PTSD). To carry this out, members of this team with significant expertise in mental health and suicide prevention will collaborate with other teams engaged in the Total Brain Diagnostics (TBD) Proof of Concept linked submissions. As a first step, we will create a unified/harmonized dataset of measures collected as part of the Long-Term Impact of Military Brain Injury (LIMBIC) and Translational Research Center for TBI and Stress Disorders (TRACTS) protocols. Based on LIMBIC and TRACTS longitudinal data collection, clinical and physiologic biosignals/functional measures will be available. The goal of this mental-health focused TBD submission will be to explore associations between physiologic measures and mental health outcomes, including depression, anxiety, substance/alcohol use, PTSD, and suicidal thoughts and behaviors. Specific efforts will focus on identifying key objective, functional physiologic measures within the harmonized longitudinal dataset which predict: 1) the presence of mental health outcomes/conditions (e.g., symptoms, suicidal thoughts and behaviors) after combat-related mTBI; and 2) distinct trajectories of mental health outcomes/conditions (e.g., symptoms, suicidal thoughts and behaviors) post-combat-related mTBI. Study Aims are as follows: Aim 1. Work with the LIMBC- TRACTS harmonization team to con...