MONDAY, Dec. 8, 2003 (HealthDayNews) -- People who are easily stressed are more likely to suffer the memory loss caused by Alzheimer's disease than their more relaxed peers, a new study finds.
There was "an extraordinary decline in memory" among the older people who tested highest on a standardized scale of susceptibility to stress, says study leader Robert S. Wilson, a professor of neurophysiology at Rush University Medical Center in Chicago.
"This suggests to us the likelihood that over a lifetime, a chronic experience of stress somehow down-regulates the brain region that governs stress response," says Wilson. "Unfortunately, that part of the brain also regulates memory."
The finding raises the possibility that treating stress-prone people, perhaps with antidepressants, can help prevent memory loss, Wilson says, but that is a relatively distant prospect.
"It is too early for us to start treating people on that basis, but it is not too early to do tests," he says. "In animal studies, antidepressant therapy does have some effect. Also, there is some indication that physical exercise might block the effects of stressful experience."
The finding, reported in the Dec. 9 issue of Neurology, comes from the Religious Orders Study, which has followed nearly 800 Catholic nuns, priests and lay brothers whose average age was 75 when the study began.
Their vulnerability to stress was measured by a rating scale using responses to such statements as "I am not a worrier" and "I often feel tense and jittery." Within five years of taking the test, people in the top 10 percent of susceptibility to stress were twice as likely to develop the memory loss caused by Alzheimer's disease, compared to those in the bottom 10 percent, the researchers say.
One unexpected finding came from anatomical studies of the brains of the 141 participants who died during the study. The brains of those who suffered memory loss did not contain the plaques and nerve cell tangles that are well-known abnormalities of Alzheimer's disease.
"The interesting thing is that stress proneness does not predict the pathology of Alzheimer's disease," says Dr. John C. S. Breitner, director of the Geriatric Research, Education and Clinical Center at the Veterans Administration Puget Sound Health Care System in Seattle, who wrote an accompanying editorial in the journal. "What it predicts is how those brain centers get expressed in terms of dementia."
Preventive treatments might be difficult because vulnerability to stress is "a stable aspect of personality" that is not easily changed, Breitner says. But treatment could be possible if depression is eventually found to be a major factor in susceptibility to stress, he says.
"Depression is an archetypical treatable disorder," Breitner says. "And a lot of depression doesn't get recognized."
Another question, Wilson says, is when treatment should begin. "We really aren't sure at what point in lifespan this [the onset of memory loss] occurs," he says. "We could be seeing it in old age because it takes many years to occur. We really need to understand how it works."
More studies are needed of larger and different groups of people to verify the finding, Wilson says. But there are some "really exciting" possibilities if it is proven true, he says.
"The trait of stress proneness is something we all have to a greater or lesser degree," he says. "A lot of this risk might be decreased by medication or lifestyle changes."
Meanwhile, Wilson adds, it's well to remember that "people have known for a long time that trying to take life less seriously is a good thing."
For more on Alzheimer's disease, visit the Alzheimer's Association. For tips on stress management, visit College of Saint Benedict, Saint John's University.