We have a friend who is a bomber pilot. Acting under the info of certain "intelligence" people, her group was ordered to bomb a particular building in Iraq. As it turned out, it was a school. It has been a couple years or so and she still has nightmares.
There was a bit on the radio the other day that there have been suicides because some of the soldiers can't handle killing non-combatants. US Military command has its head stuffed up its 6.
I don't see why a drug should help someone in her situation. If people didn't react like she did our species probably wouldn't be here. Sometimes we are just meant to feel crummy IMO.