I saw Dr. Frank Ochberg speak at a "Veterans and Trauma" Workshop at the Omega Institute in the Fall of 2013. He was a very charismatic and pleasant speaker with some interesting perspectives. The video above talks a bit about the physiological changes in the brain that are being studied by scientists and doctors to determine if post-traumatic stress is caused by specific parts of the brain when someone has experienced trauma. They are also trying to ascertain why some people seem to develop ptsd and others don't. He speaks about what he knows, but also points out that there is still room for much more research and that there are doctors out there that know a lot more about it that he does. I admire that he is willing to know what he knows, but is also willing to learn about what else might still be out there.
I think the most important thing that we can take from this is that we aren't crazy. PTSD doesn't mean you are crazy, it means you have been traumatized in some way and there may be physiological reasons for the symptoms that you currently experience. When we look at PTSD from a physiological standpoint it gives us room to develop understanding for why we are as we are, instead of placing judgment for the emotional stance of not meeting the expectation how we think we should have responded to what happened to us.