Hippocampal size and PTSD

The hippocampus is a region of the brain involved in memory and how we interpret the world around us. MRI (magnetic resonance imaging) studies have shown that the hippocampus shrinks in people with chronic post-traumatic stress disorder (PTSD) and that a smaller hippocampus could make people more vulnerable to the condition. A team of researchers, led by Brigitte A. Apfel from the San Francisco Veterans Affairs Medical Center, compared hippocampal volumes in veterans from the Gulf War. Some had developed PTSD and recovered from it, others had chronic PTSD and others had never had it. The study found that those veterans who had recovered from PTSD had larger hippocampi than those who had not recovered and were similar in size to those who had never had it. The study supports the idea that a smaller hippocampi is a risk factor for PTSD. This could be because common biological factors make people have smaller hippocampi and be more vulnerable to stress or that stress early in life makes people's hippocampi smaller and increases their vulnerability to stress later on.