Older servicemen who have had post-traumatic stress disorder (PTSD) have almost twice the risk of dementia compared to soldiers without PTSD. Dr Kristine Yaffe of the University of California, San Francisco studied 181,098 veterans of whom 53,155 had PTSD. After taking into account other risk factors associated with dementia such as depression and traumatic brain injury the veterans with PTSD had double the risk of developing dementia. Over the course of the study 10% of the veterans with PTSD developed dementia compared to just over 6.6% of those without PTSD. It is not known why there should be this link but some studies have found a link between PTSD and a shrinking of part of the brain called the hippocampus which is involved in memory and in people's response to stress.
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