]http://psychcentral.com/disorders/sx32.htm[/url] PC link to PTSD details.
Any event where someone meets overwhelming fearful circumstances might be a cause of developing PTSD.
With regards to the trait: "This trait is normal--it is inherited by 15 to 20% of the population, and indeed the same percentage seems to be present in all higher animals. " I wonder how this is gathered, and how it is differentiated... for ANY animal I know would react to most of the stimuli that the inventory presents...and ANY animal would also know how to correct the situation: fly or run away!
I'm not bashing the information, really. I am an empath, so I know quite well about being aware of my surroundings...in the universe sometimes!
TC!