They return from war bearing scars. Photographer David Jay puts the disfigured bodies of veterans who fought in Iraq and Afghanistan at the center of The Unknown Soldier, a photography exhibition that debuted last year in Washington, D.C. But the emotional trauma of war remains largely hidden from view. Nearly 20% of soldiers who returned from Iraq and Afghanistan have reported symptoms of post-traumatic stress disorder or major depression. This has led to an increase in clinical research on mental trauma—investigating therapies ranging from the use of MDMA (a psychoactive recreational drug) to nerve stimulation. In January 2016, Cohen Veterans Bioscience, a mental health care organization, partnered with McLean Hospital in Belmont, Mass., to launch the world’s first brain bank to focus exclusively on PTSD and traumatic brain injury. The research project aims to provide a greater understanding of trauma’s neurobiology and inform new diagnostic and treatment strategies.