Post-traumatic stress and traumatic brain injury have been called the signature wounds of the Afghan and Iraq conflict. Since 2001, about 5 percent of the over 2.7 million servicemembers deployed in support of the wars in Afghanistan and Iraq were diagnosed with PTS. And from 2000 through September 2015, there are over 339,000 TBI cases diagnosed, with most of these being mild TBI diagnosed in garrison locations. With the significant impacts that both PTS and TBI have made on our servicemembers and veterans, it is important to better understand the causes of PTS and TBI, and develop measures to treat and eventually prevent PTS and TBI. While both Department of Defense and Veterans Affairs have made significant research investments to learn more about PTS and TBI, leading to major advancements in diagnosis and treatments, more work must be done on prevention.