Without implying in any way that "personality traits = destiny" on this topic, because that would be patently unfair and unreasonable, a recent Yugoslav study quoted in Psychology Today indicates that personality traits may affect experience of PTSD. In general, the subjects studied who had experienced the greatest exposure to combat trauma were also the ones who suffered the most PTSD, but they also found that subjects who had certain personality traits reported PTSD more frequently than others in the study.
According to the article, "Inge Bramsen, a psychologist at Vrije Universiteit in Amsterdam, tested 572 men who participated in the United Nations Peacekeeping Force in the former Yugoslavia for PTSD. Men who reported seeing the highest number of stressful events—shootings or dead people, for example—showed the most severe symptoms. But those who rated highest on personality traits such as negativism and paranoia before deployment also tended to show more signs of PTSD later. A hostile person may see more personal menace in events than others do, says Bramsen. An anxious person may also cope with stressful situations less effectively.
Bramsen believes that a better understanding of what causes PTSD might help to protect soldiers and others sent into harm's way. But, "I think we will never be able to prevent PTSD," she says. "It is a normal reaction to an abnormal situation."