Blacksheep. I suggest you take a look at a book called 'A War of Nerves: Soldiers and Psychiatrists in the Twentieth Century' by Ben Shephard. Very interesting read and it even manages to address some of the questions you raise.
e.g. It begins at the chronological intersection of modern warfare and psychological medicine during the Great War and examines this troubled marriage through the periods of shell-shock (World War I), combat fatigue (World War II), and post-traumatic stress disorder (Vietnam, Falkland campaign, and the Gulf War).