This is something that most therapists ponder at one time or another… because the external event is only one piece of the puzzle. There are plenty of other factors that come into play. I discuss this in detail in Invisible Heroes, but the short answer is that we also need to consider these factors:
- How sensitive, how easily irritated is the person’s inborn neuronal system?
- How many previous traumas have they experienced?
- How psychologically fragile or resilient is he or she to begin with?
- Is it, in fact, a he or a she? (Women and children are more likely to acquire PTS than men, from the same event(s)).
- Was the person inebriated at the time of the traumatic event? Drunkeness turns out to be a bit of an innoculator.
- Similarly, how well-educated? (also found to be protective to a degree.)
- How much social support does this person have?
There’s also the differing nature of the traumatic event. Variables to consider:
- Proximity – how close was he or she to what was going on?
- Duration – how long and/or frequent was the exposure?
- Brutality – events characterized by human ugliness have a greater impact on PTS than even degree of injury
- Betrayal – ditto.
- Unpredictability creates more distress and symptoms of PTS than regular abuse you can set your watch by.
- Being trapped is a very powerful generator of PTS.
Additionally there are strong correlations with tendencies to dissociate during and after the traumatic event. There are more factors, but these are some of the main ones. Epidemiology and clinical research reveal more and more every day. But those are some of the reasons you can’t tell who’s going to get PTS from the catalyzing events alone. It’s a complicated formula. The only way you can diagnose PTS is by the combination of symptoms the person is experiencing – not by what happened to them.
I hope this casts a little light on this complicated issue. Thanks for asking.