Yes. I think that is exactly the case in the sense that early or repeated exposure to stressors predisposes you to PTSD, for sure. Then who develops PTSD and who doesn't? We still don't understand that really well, but we know some of the issues and incidents that trigger the response.
When you talk about kids being exposed to traumatic events, it is really the same across the world, whether they come from a war zone or.... There was an earlier discussion about the immigrant populations versus refugees being vulnerable to mental heath conditions, which has to do with the level of stress exposure they've had, especially in the early years of life, because it seems to be an accumulative toll at times, such that eventually a straw will break a camel's back. That's the result of an accumulation of stressful experiences.