Posttraumatic Stress Disorder Linked to Dementia
Study Shows Veterans With PTSD More Likely to Develop Alzheimer's Later in Life
June 7, 2010 -- Older veterans who suffer from posttraumatic stress disorder (PTSD) are almost twice as likely to develop Alzheimer's disease and other age-related dementias as veterans without PTSD, a study shows.
The study is among the first to link combat-related posttraumatic stress disorder to dementia later in life, but it is not clear if having PTSD increases the risk for late-life dementias or if recurring PTSD is an early symptom of dementia in older veterans, Deborah Barnes, PhD, of the University of California, San Francisco tells WebMD.
"We can't say from a study like this one that PTSD causes dementia," she says. "But if it does, one theory is that stress is to blame."
There is evidence that chronic stress may damage the hippocampus, which is the area of the brain that is critical for memory and learning.
PTSD and Alzheimer's
Barnes and colleagues followed more than 180,000 mostly male older veterans for seven years, including just over 53,000 with a diagnosis of PTSD. None had dementia in late 2000, but roughly 31,000 (17%) had been diagnosed with the degenerative memory and thinking disorder by late 2007.
The veterans with PTSD had about an 11% risk of developing dementia over the seven-year period, compared to about a 7% risk among veterans without the stress disorder.
After adjusting for other risk factors related to the development of Alzheimer's disease and other late-life dementias, the veterans with PTSD were 77% more likely to develop dementia as those without it.
This finding remained even after researchers excluded patients with a history of head injury, substance abuse, or clinical depression.
The study was funded by the U.S. Department of Defense and the National Institute on Aging. It appears in the June issue of Archives of General Psychiatry.
"Just as with depression, it is common for people to cycle in and out of PTSD for many years or even decades," Barnes says. "One message is that when we see PTSD symptoms in older veterans that could be a sign of other problems."