hi! not discouraging other responses, but FYI you'll find some info on this in the FAQ (link on sidebar):

Post Traumatic Stress Disorder before the modern era

Well, from my reading, "shell shock" became a pretty well-known mental scarring during WW1, though I'm not sure about anything else.
Source: "A World Undone: The Story of the Great War, 1914 to 1918," by G.J. Meyer

Wikipedia has a pretty good overview of it here, and "A World Undone" covers it well enough to explain it and put it into context.