Posttraumatic stress disorder and traumatic brain injury: are they mutually exclusive?

It has been suggested that posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI) must be mutually incompatible disorders. However, growing empirical evidence has begun to question this. Evidence suggests that although PTSD may be relatively rare among the TBI population, some TBI patients seem to develop PTSD. We suggest two theoretical routes through which PTSD might develop in TBI patients: through nonconscious processes in individuals who are subsequently amnesic, but who were conscious at the time of the traumatic episode and through subsequent appraisal processes in individuals who were unconscious during the traumatic episode.