Hi Olga,

As always, nice to chat with you.

I did a Google search using:

post-traumatic stress disorder size

and found what I was looking for (URL below) but 
much more than I expected.

Most of my knowledge of PSTD had come from 
Judith Lewis Herman's book 'Trauma and Recovery'
(we actually consulted with her - her office is in 
 Cambridge) but there's clearly a lot more 
information emerging.

Always something fascinating and challenging --

   Regards,
     -Fred


http://www.nature.com/neuro/press_release/nn1102.html


A RISK FACTOR FOR POST-TRAUMATIC STRESS DISORDER 


Post-traumatic stress disorder (PTSD) develops in response to traumatic events, such as kidnapping or war. Its symptoms include flashbacks, nightmares, jumpiness and emotional problems. PTSD may be more likely to occur in people with pre-existing damage to the hippocampus, a brain area involved in memory and stress responses, reports a paper in the November issue of Nature Neuroscience. This finding could help predict which individuals may be particularly sensitive to stressful experiences.

Previous work had shown that the hippocampus is smaller than normal in PTSD patients. Because stress can damage this brain region, though, most researchers concluded that PTSD had caused the hippocampus to shrink. No one had looked at brain scans before and after PTSD developed, and so it remained possible that the brain damage was present before the trauma. In the new study, the authors addressed this question by examining identical twins in which one brother was a combat veteran of the Vietnam War, while the other had remained at home. As expected, the hippocampus was smaller in combat-exposed brothers who developed PTSD than in other veterans who did not develop the disorder. But to the researchers' surprise, this brain region was also small in the stay-at-home brothers of the PTSD patients. In other words, the hippocampal size of the twin who was not exposed to combat predicted whether his soldier brother would develop PTSD. Because identical twins typically have similar brain structures, this finding suggests that the hippocampus was probably small in the PTSD patients before the trauma, which may represent a risk factor for the development of PTSD. 

In an accompanying News & Views article, Robert Sapolsky cautions that much work is needed before a definite cause-and-effect relationship between PTSD and brain trauma can be determined.









When The Past Won't Go Away

In the DSM-IV, Post-Traumatic Stress Disorder (PTSD), is defined by four variables: 

(1) exposure by personal experience or by witnessing an event which threatened or caused death and severe
injury to self or others and was accompanied by a response from the victim of fear and helplessness; 

(2) a consistent re-experiencing of the traumatic event through flashbacks, nightmares or episodes of intense
distress to events of any similarity to the original trauma; 

(3) persistent avoidance of all stimuli related to the original event to include an avoidance of thoughts,
feelings, conversations, or other situations that have similarity to the trauma, a detachment from others, and
a numbing of affect; and 

(4) ongoing symptoms of increased arousal as a result of the trauma to include sleep difficulties,
irritability, concentration difficulties, hypervigilance, and an exaggerated startle response. In addition,
the duration of these symptoms is at least for one month and PTSD must cause significant clinical impairment
in social, occupational, or other important areas of functioning. 



Google search:
post-traumatic stress disorder size