It's been around a lot longer. We've called it Shell Shock, War Neurosis, Battle Fatigue and several other things. It's well documented. PTSD, imo, is just another layer of indirection when referring to trauma. It's name provides significantly less meaning than something like "shell shock" which gets right to the point of the matter. PTSD was certainly appreciated. Patton famously got a reaming from Eisenhower for how he treated shell shocked troops during the war.