Was there PTSD in the ancient or medieval world?

They might have felt much less conflicted by killing because they did not come from a cultural background where killing your enemies is usually prohibited. Our justification as a culture for warfare starts with "of course, killing is bad, but..." and then looks into when it is allowable.

Many of the examples we have of things that look like PTSD are from failed rebels, people who were involved in civil wars, or people who had been disgraced. That would mean that they experienced the same sort of reaction to a stressor that they couldn't process but that the type of stressor that might trigger such a reaction was fundamentally different.

I wonder how much video games have do to with this perception? In a video game, you have a Kill-Death ratio, not a Kill-Death-Prisoner-Flee-Serious Injury-Light Injury ratio (I know some games have a more sophisticated model, but still).

I do not have the classic "first page" symptoms from the DSM-V, as I like to call them. These are the flashbacks, intrusive memories, noise sensitivity - the common image of classic PTSD. I believe I do not have them because I never personally compromised my own value system and caused harm to innocent people. I did, however, witness milder events to an extent frequent and prolonged enough to cause a deep unmovable certainty that the world is tragically fucked up. That lead me to have all kinds of angsty aggressions in the direction of "the system" or "the world" at large. This anxious, overdriven fearful discontent lead me to be fully certain that life was tragic, and all around convinced that there was a conspiracy to make it so. It has taken over a decade for those certainties to subside. Some of it was immaturity, most of it was evidence.

My Marine battalion made front page NYT news for its suicide rate. Many Marines have not had the experience I had. I believe this is because they were younger than I was (25) and many went on one or even two combat deployments to Iraq prior to ours. They have done a sadly effective job at killing themselves. I believe the reason for this (with no evidence) is because these men were prone to enjoying and seeking opportunities to kill.

Apart from that guessing game, I also believe that the symptoms of PTSD are all-around easy to suppress and make look like other things. Most of the behavior associated with "toxic masculinity" as it is currently being called can be instead directed towards a PTSD diagnosis or some kind of traumatic reaction. I am sure of this. So the fact that the ancient world had all these orders and so forth with vows and tight-knit little clans are all a sign to me that they were just like the soldiers returning from WWII who became bikers; they were rattled badly. They had to put on that cold, tightly-wound demeanor by force of the nervousness that lay underneath. All those sovereign military orders and all that? They were all PTSD clubs.

In opposition to this ideal, there is a book titled "On Killing" which describes why not all killers are susceptible to PTSD. I believe the book is fairly accurate in its claim, however it does exactly what those old military orders did: it creates a warrior ethos which allows for an in-group admission of the experiences while keeping the out-group afraid of the warriors. According to the book, there is a subsection of humanity that are naturally capable of killing without it being contrary to their values. They do not revel in it as some do. They are not triggered by it as many are. This is the chivalrous vision of being a trigger-puller.

My experience of events which ought to be traumatic is mostly that they only return to bother us if there is some behavior that was contrary to the individuals values. Those vary. To move the slider as far to the (?) as is necessary to justify killing on moral, religious, personal, political/tribal/cultural grounds, and showering killers in rewards after the fact, including great tales of valour, etc that make all those sacrifices worthy: that is the means of shielding the society from the reality of there being a fraction of the people who are extremely fucked up from having hacked/shot/blown people to pieces.

One final note: it was far more common to die from wounds and disease. Many people just plain didn't survive the wars due to wounds and plagues. Or they were assimilated somewhat into their enemies worlds and never returned to exactly the same place where people could say: "holy shit, you're different."