An unexpected side-effect of brain trauma has revealed a reduction or complete absence of post-traumatic stress disorder (PTSD) in Vietnam War veterans. Brain scans of nearly 200 veterans who received head injuries during battle, showed that trauma to specific areas of the brain acted as a protective mechanism for the development of PTSD.
PTSD is an anxiety disorder that follows exposure to assaults or events that are traumatic to experience and/or observe. People with PTSD frequently report a sense of emotional numbness with those they were previously close to. Flashbacks, nightmares, increased irritability and aggression are all symptoms. It is estimated that just over a million Vietnam veterans have been diagnosed. Millions more people suffer PTSD as a result of assaults, rape, childhood abuse, natural disasters or other traumatic events. Although mild cases of PTSD can be helped by counseling or cognitive therapy, many other cases require anti-depressants in order to cope. PSTD is associated with drug misuse, alcoholism and suicide.
Jordan Grafman, Ph.D., a senior researcher at the National Institute of Neurological Disorders and Stroke (NINDS), in Maryland, scanned the brains of 193 veterans who had received brain injuries. Grafman and his team also scanned 52 brains of men who had seen combat but were uninjured. Grafman noted that some patients had clear memories of traumatic events but they appeared unaffected by them.
When the veterans were divided into groups depending on whether they had a history of PTSD it became clear that those with a certain type of brain injury seemed to have an almost complete absence of PTSD symptoms.
The two areas of brain affected were the amygdala and the ventromedial prefrontal cortex. The amygdala is an almond shaped bundle of nerve fibres that has a role in emotional states, emotional memory, and the interpretation of anxiety, fear and painful experiences. The ventromedial prefrontal cortex is a larger structure found towards the front of the brain. This area has long been implicated in the processing of the fear response.
Grafman found that none of the 50 veterans with injury to the amygdale experienced PTSD. Of those with an injury to the ventromedial prefrontal cortex, only 18 per cent experienced PTSD symptoms. People with PTSD overproduce the chemical corticotrophin releasing factor (CRF) which is strongly associated with the body’s reaction to stress.
“ . . if you can moderate the activity of the amygdala or the ventromedial prefrontal cortex, you might control the person’s memories in such a way that they don’t develop full blown PTSD,” said Grafman.
The drug propranolol seems to protect against PTSD and another drug that blocks CRF is currently undergoing trials in people with anxiety and depression.
Published On: January 24, 2008