RecruitingDevice studyThe PREVENT Resilience StudyPTSD is one of the most universal and severe psychiatric disorders whose incidence continues to rise due to the common exposure to severe trauma in the United States and worldwide. After trauma, a proportion of individuals maintains high symptoms of PTSD and depression, which can persist for years. The early weeks following trauma present a unique opportunity to deliver early interventions that can prevent chronic PTSD and depression from occurring, and the researchers propose a brain-based intervention that will reduce reactivity to threat, an early risk mechanism for chronic PTSD. This study is being done to learn more about whether brain stimulation in the weeks after a trauma can change brain activity that is linked to Post-Traumatic Stress Disorder (PTSD).