New research presented yesterday suggests that post-traumatic stress disorder (PTSD) may be the result not only of exposure to a traumatic event, but also from a pre-existing vulnerability to stress.
The study, by researchers at Massachusetts General Hospital and the VA Medical Center in Manchester, New Hampshire, also found that exposure to a traumatic event may cause physical brain damage.
Researchers studied the brains through neurological examinations and MRIs of more than 100 Vietnam War combat veterans who had a twin who did not serve in combat. While both twins shared some impairments in neurological functioning, only the brother who served in combat had brain atrophy in an area linked to decision-making.
According to the researchers, “We discovered a number of abnormalities in PTSD combat veterans not shared with their twins and . . . we infer that the abnormality was caused by combat. One of these is increased heart rate response when the combat veteran is startled. Another example is loss of gray matter in the rostral anterior cingulated cortex, [a part of the brain] which plays a role in inhibiting the fear response.”
Researchers suggest that a stressful event acts as a triggering event that may play a critical role in determining whether someone is at risk for posttraumatic stress disorder.
“We have identified several abnormalities that combat veterans share with their combat-unexposed twins that must represent risk factors. They could not have been acquired as a result of combat since their twins also have them,” noted the investigators.
“Traumatic stress can alter both brain structure and brain function. Our findings tend to refute the suggestion that people with PTSD would have probably had [psychological symptoms] even if they hadn’t been exposed to a traumatic event.”
The paper was presented Tuesday at the American College of Neuropsychopharmacology’s annual meeting.
Source: American College of Neuropsychopharmacology