Raise Alzheimer's Risk
Susceptibility to psychological distress
seems to be associated with the risk of Alzheimer's disease, researchers
in Chicago report in the current issue of the journal Neurology.
Because chronic stressful experience
is linked to structural changes in the brain and with impaired
learning and memory, Dr. Robert S. Wilson and colleagues at Rush-Presbyterian-St.
Luke's Medical Center hypothesized that a propensity to experience
psychological distress is related to the risk of Alzheimer's disease.
To investigate, they analyzed data
from the Religious Orders Study, which included 797 individuals,
average age 75 years, who were free of dementia at the start of
the trial. The subjects underwent complete neurologic examinations
and completed a test for signs of neurosis. At annual follow-ups,
the subjects also underwent a battery of 19 tests that measured
During an average follow-up of
about five years, 140 individuals were diagnosed with Alzheimer's
After adjusting the findings for
age, sex, and education, Wilson's team found that each one-point
increase in test score for distress-proneness was associated with
a six percent increased risk of Alzheimer's disease and a seven
percent decline in mental capacity. Compared with people with
the lowest scores, the risk was approximately doubled in persons
with the highest scores.
Episodic memory, which the investigators
note is primarily mediated by formation of the hippocampus, was
more affected by symptoms of neurosis than were other mental functioning
systems, such as word memory, and visual and spatial ability.
The authors were surprised to see
that this trait was not associated with the extent of plaques
and neurofibrillary tangles in the brain, which reflects severity
of Alzheimer's disease. They suggest that the association between
chronic psychological distress and Alzheimer's disease "probably
reflects neurobiologic mechanisms other than the pathologic hallmarks
of Alzheimer's disease."
Wilson notes in a journal press
release that antidepressants and other drugs may block the adverse
effects of stress. "But much more research is needed before we
can determine whether the use of antidepressants could help reduce
the risk of Alzheimer's disease."
Regardless of whether higher scores
on symptoms of neurosis are related to or are early signs of Alzheimer's
disease dementia, this study demonstrates that distress-proneness
predicts an increased risk of Alzheimer's disease in an elderly
population, Dr. John C. S. Breitner, with the University of Washington
in Seattle, and Dr. Paul T. Costa, with the National Institute
on Aging in Baltimore, remark in a related editorial.
SOURCE: Neurology, December 9,
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