Shell shock was sort of a "mistake". When soldiers in WW1 began displaying symptoms of what we know as PTSD today, the officers initially thought they were just being pussies. But then the symptoms persisted, even after the troops spent 5 weeks being shelled almost non-stop in a bunker/trench network. Doctors initially believed this to be "shell shock", a *physical* condition caused by the repeated, sustained barrage of shells- they believed that this was causing some kind of brain damage, leading to the symptoms. I think by the end of WW2, they had figured out it wasn't the shelling itself that was causing this. They had identified this condition as "Battle Fatigue", which is just what it sounds like. It wasn't until like a decade after 'Nam when PTSD became more fully understood. Interesting fact about PTSD in the ancient world: When a Roman was selling a slave, he was legally required to disclose two things to the potential buyer- Has the slave attempted suicide? Obvious question to ask, they wouldn't want to buy a slave that'd off himself in a few days. The other question: Has the slave ever been mauled/attacked by a large animal, such as a wolf, bear, lion, etc.? Now why would they ask that question? **Because PTSD most commonly manifests in people who have been mauled by animals.** The Romans knew that this fucked up the mind of the victim. **They never were required to disclose whether or not the slave had been in battle.** There was probably a good chance that the slave you're buying was an enemy soldier, captured and allowed to live under the condition that he behaves as a slave. He may have watched his best friend hacked to bits, his brother ran through with spears, he was probably beaten into submission- but nobody cared about any of this. Why not? **BECAUSE BACK THEN, IT WAS EXPECTED OF MEN TO FIGHT IN BATTLE. IT WAS NORMAL.** Today, we are raised from birth being told "All violence is bad, no matter what. All killing is bad, no matter what." And then we join the military at age 17-18, and they have the task of undoing all of this "violence bad" bullshit and turn you into a warrior who would aggressively engage and kill threats. This has to mess with your mind.