I hope I don’t miss any of these questions. Yes, all of these studies were NIH funded. We collected DNA, but we did not do that part of the analysis. Other researchers did and they have published their results. I have read them, but I am not a co-author on the study. There were different numbers of people in each study, but the average is 200-300 people or so. You can’t really have a control group for a traumatic event. That would require that we know in advance that something bad was going to happen, and then expose half of the people to the trauma randomly and half not. Thus, these are not experiments. We conducted in-person interviews with each person, and we used something called the CIDI diagnostic interview, which allows a field researcher to diagnose people with mental disorders. There are follow-up studies on several of the studies we did. I don’t think so on the bioterrorism ones, because we found a low incidence of PTSD, but on the other ones there are follow-ups. If you are curious, Carol North, is an expert in the field who has published dozens of articles on it, and her articles could continue on from where I went.
You’ll notice on the model how it said genetic differences were linked with childhood trauma to lead to a vulnerability to mental disorder, layered on top of that is excessive stress. So, genetic differences never appears by itself as a cause for disorders. This was originally called the diathesis-stress model. Now, I see it called the stress-vulnerability model more often. We know that people with a genetic predisposition to PTSD can be prevented from getting PTSD after a trauma, because there are interventions called Crisis Stress Debriefings that happen immediately after something like a natural disaster or some military events that can reduce the onset of PTSD. As far as predicting who will get PTSD versus who won’t, I don’t think we have the capacity to do that yet. If we did, trust me, the military would be jumping on it.