I once heard a neuropsychologist declare that one could not have posttraumatic stress disorder (PTSD) and post concussion syndrome (PCS). If you do not remember the trauma you are precluded from having PTSD since you do not remember the trauma. Therefore if you have organic PCS, damage to the brain, and your memory of the trauma is absent, you PTSD. The referenced neuropsychologist worked for the defense trying to disprove the existence of brain injury in the case.
There are many forms of memory and only some of these may be critical for the development of posttraumatic stress disorder (PTSD), reports a new study by researchers at the University at Albany and the University of California Los Angeles. Their findings, published in the current issue of Biological Psychiatry, suggest that even with no explicit memory of an early childhood trauma, symptoms of PTSD can still develop in adulthood.
There are case reports of people who have experienced terrible life events that resulted in brain damage, some of whom developed syndromes similar to PTSD even though they had no recollection of the event itself.
These reports suggest that explicit memory may not be an absolute requirement for PTSD, whereas other forms of learning, such as fear conditioning, may be required.
Explicit memory is the type of memory that can be voluntarily recalled from prior experience and articulated.
The findings are consistent with the idea that one can get both post concussion syndrome and post traumatic stress disorder.