Here is the fourth section of of The Post-Traumatic Gazette #1, copyright Patience Mason 1995, 2005, What are Post Traumatic Stress Reactions?

It is normal to be affected by trauma, butt not every one who is traumatized gets diagnosable Post Traumatic Stress Disorder. There is a great range of post traumatic reactions because people are different, have had different life experiences, and have different capacities and skills. Some people do okay during the trauma, others crack. Some people have no reaction till another trauma, years later. Most people will find that post-traumatic reactions come back when there is subsequent trauma. Some people seem to alternate periods of extensive numbing with periods of explosive hypervigilant behavior or intrusive reexperiencing (the third category of PTSD symptoms). If the alternation is severe enough, they will never be diagnosed with PTSD because the symptoms won’t be present at the same time, but their lives will be scarred by the trauma nonetheless.
These PTSD survival skills tend to become less appropriate and less effective with time and can wind up being really crippling ineffective behaviors. For a healing perspective, we need to keep in mind that the behaviors of trauma survivors are direct evidence, sometimes the best evidence, of what they have survived, of their experience. They are also evidence of ingenuity, creativity and courage. Reframing the behaviors in this light can be an enlightening experience for the survivor, families, friends, and therapists. Instead of being bad behaviors, they become useful evidence about the nature of the trauma or traumas and the guts and brains of the survivor, who, after all, survived.
Along with three numbing symptoms and two hypervigilant symptoms, to be diagnosed with PTSD, survivors must also reexperience the trauma in some form. The most dramatic of these reexperiencing phenomena, the flashback, forced the recognition of PTSD by psychiatrists.
Psychiatrists were trained to deny that traumatic events did affect people despite evidence from concentration camp survivors and World War II veterans. When Vietnam veterans were having flashbacks in the halls of the VA hospitals, some professionals were able to break this denial and see real people really suffering. They had to acknowledge the flashbacks, so they created a diagnosis centered around reexperiencing reactions. Psychiatrists tend to think of it as a wierd reexperiencing disorder instead of a natural-but-now-not-so-useful survival-skill disorder. I think a more healing perspective focuses on the effectiveness of the skills the person developed to survive, (hyperalertness and numbing). The other approach makes it easy to stigmatize survivors for the very behaviors which helped them survive.
Apparently sharing about traumatic experiences is also necessary for human beings because people who can’t, for whatever reason, develop reexperiencing symptoms. Survivors are reexperiencing when they cannot stop thinking (or talking) about the trauma, when they are dreaming about it, or flashing back to the experience, feeling like it is happening again, even if they are drunk or on drugs. Reexperiencing also includes being upset on anniversaries of the trauma or by things that remind the survivor of the trauma. New wars, highly publicized rape, murder, battering and incest trials all affect survivors. Having a physiological reaction to something that reminds the survivor of the trauma is also a form of reexperiencing. The sound of a helicopter overhead sends a rush of adrenaline through many veterans. Someone raped in a stairwell may find herself sick and dizzy in any stairwell.