dr. ann mckee and her team are looking for clues. they're examining hundreds of brain samples donated by patients diagnosed with ptsd. dr. ann mckee: we've always made the assumption that these are microscopically, that don't have any damage or lesions. sure because no one has ever looked. study of ptsd is the first of its kind. technicians are looking for brain disorders hoping to find better treatments. dr. mckee: there are certain treatments that reduce inflammation, certain treatments that heal blood vessels. if any of these structures are going haywire, then we can focus our treatment on those things. emily: it will take time but for those suffering now, there are therapies that can help. gene stein launched "guitars for vets" in 2013 at the brockton v.a. teaching veterans diagnosed with ptsd how to play and, by playing, to heal. gene stein: you're not thinking about your problems. you're thinking about, "how do i play this e chord?" or "how do i not have my pick hit the wrong string?" that can be a huge release for a veteran. i