I suspect we'll find that there's a difference between what was called shell shock (brain damage from blast waves) and PTSD (psychological trauma), and that it's possible to suffer from one or the other, or both.
http://www.nytimes.com/2016/06/12/magazine/what-if-ptsd-is-m...
(NOTE: This is for some of what goes under the umbrella term "PTSD", so of course not for every single diagnosis. Only the people exposed to such shock waves.)