Impact of Pre-Military Life Experiences/Exposures on Active-Duty Service Members' Psychological Health

The goal of this observational study is to learn about the impact of historic and current Traumatic Brain Injuries on a Marine Battalion. Its main objectives are: * Establish individual mental and physical performance profile and brain health baseline in Infantry Marines * Develop predictive models to identify early signs of mental and/or physical degradation that can help predict "red-line" behavioral events and degradation in brain health. * Gather insights that will lead to developing personalized, evidence-based interventions to restore mental and physical performance. * Increase warfighter self-knowledge and personal awareness to monitor and maximize performance. Participants will wear wear smart watches and analyte sensors to track their real time physiological and sleep measures and complete subjective and psychological measures in a custom research app.