In psychology, there is a concept of “culture-bound disorders”. Traditionally, these seem to be very unusual disorders that are extremely common in some cultures but not in WEIRD cultures. I think maybe the psychologists are getting this backwards; maybe some of the proper disorders in the DSM are actually culture-bound to WEIRD culture, and I think the specific way PTSD is normally described may be one of these. This isn’t to say that other cultures don’t have stress reactions, but they have different stress reactions that crystallize in forms that are more “normal” to their cultures, the way textbook PTSD is effectively “normal” to our culture. I’ve read about cases where well-meaning Western counselors show up to natural disasters expecting the survivors to have textbook PTSD symptoms. At first, people hear these counselors asking about PTSD symptoms and are genuinely confused, but apparently with enough contact, the suggestion from an authoritative sounding western medical practitioner implying that this is how they should be feeling in that situation can end up inducing those very symptoms.