Look into the research that MAPS (and others) is doing with MDMA. Amazing results with people who are suffering from severe PTSD.

I expect it will be a powerful tool that can help people suffering from a wide variety of traumas. Side note, but we don’t understand nearly enough about trauma. Unresolved trauma is an enormous driver of human suffering. I think it may far more widespread and take many more forms than what the textbooks say.

I find trauma to be quite interesting. I believe it's real and significant, but what I'm trying to figure out is why, evolutionarily speaking. People were routinely exposed to very traumatic, violent things in our ancestral history, much more often than in present society. How would it have been adaptive to then respond to those events with trauma, which would seem to reduce our genetic fitness?

That is a really good question. I’ve wondered about that too. It may have provided some protection, as it may increase avoidance of future dangerous situations. It could also partially be a side effect of other useful emotional expressions. Or perhaps human behavior grew in complexity (more ways to hurt each other) faster than evolution could improve our emotional processing capabilities. It’s hard to say.

Relatedly, maybe humans had better ways of coping with trauma in the past, through communal bonds, more strongly shared world views, rituals, and so on.