“Post Traumatic Stress Disorder) PTSD is a natural response to danger, it’s almost unavoidable in the short term and mostly self-correcting in the long term. Only about 20 percent of people exposed to trauma react with long-term (chronic) PTSD.“
This May, 2015 Vanity Fair article by Sebastian Junger is an excellent look into the phenomenon that accompanies and follows traumatic events.
“I had classic short-term (acute) PTSD. From an evolutionary perspective, it’s exactly the response you want to have when your life is in danger: you want to be vigilant, you want to react to strange noises, you want to sleep lightly and wake easily, you want to have flashbacks that remind you of the danger, and you want to be, by turns, anxious and depressed. Anxiety keeps you ready to fight, and depression keeps you from being too active and putting yourself at greater risk. This is a universal human adaptation to danger that is common to other mammals as well. It may be unpleasant, but it’s preferable to getting eaten. (Because PTSD is so adaptive, many have begun leaving the word “disorder” out of the term to avoid stigmatizing a basically healthy reaction.)“