A lot of vets from previous wars came back with it too, but it wasn't diagnosed, and men were expected to be tough and not show their feelings. I don't know how the rates might compare, if that's even measurable. A couple of (probably overgeneralized) factors might be: In Vietnam, you didn't have the reassurance that the nation was behind you, or that you were bound to win, so in many cases morale was probably hurt by thoughts of "Why are we here when the South Vietnamese won't even fight for themselves"? Much of the war was in an alien jungle environment, where you never knew who was 20 yards off about to ambush you, or where the next booby trap was. Much of the war was also against irregulars, whom you couldn't always tell from civilians. WWI & WW2 were much higher-intensity wars - about 500,000 deaths for the US (compared to the high 3000's in Iraq), and that with fairly short Pacific campaigns, a year in North Africa, a couple of years in Italy, and less than a year in France, the Low Countries, & Germany. So deaths and injuries were much higher, e.g., at the end of the war, Audie Murphy, the most-decorated US soldier, was one of two remaining members of his original 150-ish man company - the other one was a cook. So I'd think that, relative to Vietnam, relatively few infantry might have been in battle for a year, while in Vietnam soldiers served 12 months and the Marines 13. Also, if they were wounded, they were more likely to die than in Vietnam, and much more likely than in Iraq. As for Iraq, it's less intense than Vietnam, but repeated deployments will hurt. Everybody has their point at which they have trouble handling stress. I'm definitely no expert - I've probably left out consideration of whole aspects of the questions.

I've seen a lot of footage and documentaries on World War II. They say that close to one third came back with severe neuro-psychological problems or Shell Shock as they called it. Some of them could no longer speak due to the trauma they endured. It's a horrible thing. With all due respect, I think your question wondering why so many Viet Nam vets came back with PTSD (and if our current soldiers are suffering the same) is absolutely insane. Why did the Viet Nam vets have PTSD?? Are you kidding????? They came back from a hell that you nor I could ever imagine. I'm sorry, but I am just dumbfounded that you even ask why they came back that way. I think that while many Iraq War soldiers are suffering severe depression, combat stress and sometimes PTSD (and I am dating one who is experiencing all three, but is managing to function) the level of carnage and terror this guys have been facing is not anywhere near as bad as the Viet Nam guys had it. And at least the military today is being very proactive at getting these soldiers into treatment and screening them for signs. In Viet Nam, they weren't so lucky. In WWII, they were just expected to deal with it.

It's like sexual harassment - the more widely acknowledged it is as a real problem, more cases are reported. And considering what some of the US soldiers have been ordered to do, I'd imagine that quite a few will come back with cases of PTSD (and that's saying nothing of the poor people living in Iraq).

I believe one of the biggest contributing factors is the fact that many soldiers saw horrific mutilation of fellow soldiers as well as civilian casualties. They were fighting an enemy that had been fighting for years even before we came into the conflict. The enemy was ruthless in the tacticts they used;ie,babies rigged w/bombs, children and women being used as bait in mine fields to lure our soldiers into targets etc. I don't think we will have as many reported cases of PTSD as back then, because we have the upper hand in this war. The tactics are different than in vietnam.

The trauma of having to kill people and watching your close comrades have the same fate happen to them. No amount of "psyching our minds for war" can eliminate all feelings. Not knowing full well who was and wasn't the enemy mave have given an increase to the problem. It certainly wasn't and isn't just attributed to Vietnam although it happen to be at a point where it was probably finally given a different name by the meds. Shell shock, combat fatigue, it was labeled different things in different wars. My uncle came back from a Jap POW camp after World War II(he was one of the lucky ones). He certainly was never the same after. Seeing your buddy lose his head courtesy of a machette can do that to a person. War is hell and EVERYONE who comes back a survivor has been changed to some degree. You can see it in their eyes when they come off the planes. But then again, you don't even have to go to war to receive a PTSD diagnosis. Any traumatic event can set the wheels in motion. The second question...It depends on how well they have been psychologically trained to handle such events. An attitude of "Well, we'll deal with those feelings later" won't work. Maybe we can get all those gang-bangers to fight over there. Alot of them don't seem to have a problem with taking a life. Might as well put it to good use.