No more stressful situation exists than combat. Before you are strangers you must kill. Beside you are friends being killed, friends you could join instantly. You're usually exhausted, filthy, and hungry. And those back home will never really understand what you’ve endured, because of battle's unique, indescribable horror.
"I remember the experience as I do a nightmare. A demon seemed to have entered my body." Audie Murphy, hero.
Compared to previous wars, World War Two was a greater horror for the 800,000 men in extended combat. Bigger field weapons meant soldiers fought in small units dispersed over more territory, without the company camaraderie that sustained WW1 doughboys. Bomber crews could kill more people from afar, but at significantly greater risk from enemy fighters and anti-aircraft fire. At sea, enemy planes and submarines could turn the mightiest warship into a sinking inferno in minutes.
One in four WW2 casualties was caused by "combat fatigue." For those in lengthy, intense fighting, the ratio was one in two. In the Pacific, where combat fatigue was most prevalent, 40% of 1943 evacuations were "mental." 26,000 psychiatric cases were reported just from Okinawa. To keep sailors from going mad anticipating kamikaze attacks, they weren't alerted to approaching planes until they absolutely had to be.
Except for a few blood-n'-guts hardliners like Generals George Patton and Curtis LeMay, the brass no longer thought combat fatigue was evidence of cowardice or a pre-war neurosis. It was a wound, albeit an emotional wound. Combat fatigue researcher Frederick Hanson discovered that evacuating a patient home, besides losing him forever as a fighting soldier, often exacerbated his condition. Hanson and others realized that battle fatigued soldiers were often, more than anything else, just fatigued. The First Armored Division reported that by giving "mentals" complete rest in a safe area near the front, plus hot meals and a bath, 50-70% returned to combat within three days.
Field psychiatrists tried other treatments too, including sodium pentathol to get men to re-live their repressed battlefield experiences and thus reach a catharsis. Flight Surgeon Jack McKittrick was more practical; he found distributing liquor at mission debriefings settled the fliers when they most needed it.
1,393,000 soldiers were treated for battle fatigue during WW2. Of all ground combat troops, 37% were discharged for psychiatric reasons. From them, the military learned valuable lessons for the Koreas and Vietnams to come.