In previous studies post-traumatic stress disorder (PTSD) had been associated with changes in brain activity. However, none of those studies were able to determine whether the changes were contributing or merely a result of PTSD.

Senior investigator Jordan Grafman, Ph.D., National Institute of Neurological Disorders and Stroke (NINDS), part of NIH, used the Vietnam Head Injury Study (VHIS) registry to find Vietnam veterans who sustained penetrating brain injuries. The study consisted of 193 veterans registered with VHIS (with brain injury) and 52 veterans with combat exposure, but no head injury. The subjects were divided into 2 groups; one with those who had developed PTSD, at some point in their lifetime, and the second group who have never developed PTSD.

Computerized tomography scans of the two groups were compared. Researchers found 2 regions of the brain that, when injured, are rarely associated with PTSD: the amygdala (a structure important in fear and anxiety), and the ventromedial prefrontal cortex (vmPFC) (an area involved in higher mental functions and planning).

According to Grafman damage to either the amygdala or vmPFC reduces the likelihood of developing PTSD. It is his hope that drugs designed to inhibit the activity of these brain regions might provide relief from PTSD. Also, deep brain stimulation, a technique used to treat Parkinson’s disease, that modifies the brain’s electrical activity might also be useful in the treatment of PTSD.