Depression and Alzheimer's Linked
Depression Boosts Risk of Dementia, but Does Not Increase During Early Alzheimer's, Studies Show
Depression and Alzheimer's Early Stages Study
In the second study, researchers from Rush University Medical Center,
Chicago, looked at participants' state of mind during the very early stages of
Alzheimer's disease and whether they tended to become more depressed.
Some experts have suggested depression is not a true risk factor but a
consequence of the disease. If that is true, depression would likely increase
as a person develops dementia.
For up to 13 years, researchers followed 917 participants of the Religious
Orders Study, which launched in 1994 and includes Catholic nuns, priests, and
monks. All were free of dementia at the study start and all agreed to donate
their brains for autopsy at death so researchers can discover more information
about Alzheimer's disease and other problems.
They were given annual exams, including tests of memory and other cognitive
skills. During the follow-up, 190 developed Alzheimer's disease. Those with
more depression at the beginning were found more likely to get it. But their
depression didn't increase in the early stages.
"We found absolutely no evidence that depressive symptoms increased
during that period [of early Alzheimer's],'" says Robert S. Wilson, PhD,
professor of neurological sciences and behavioral sciences at Rush University
Medical Center, Chicago, and the lead author.
"Even though it sort of makes sense that you would get depressed when
you are losing cognition, it doesn't seem to be happening."
The research, he tells WebMD, "goes against the idea that depressive
symptoms are a consequence not a risk factor of Alzheimer's disease."
The study is published in the Archives of General Psychiatry.
Second Opinions and Take-Home Message
The association found between depression and Alzheimer's risk was much
stronger for early-onset depression than later onset, according to other
experts. The risk between late onset depression and Alzheimer's was not
"People who have early-onset depression were found at an increased risk
of Alzheimer's disease," says Wilson, the author of the study on depression
during Alzheimer's early stages. "For those with late-onset depression, the
results are not as conclusive."
The most conservative thing to say is that depression is a risk factor, more
prominent with younger onset but also possibly operative at later ages as
well,'' says David Knopman, MD, a neurologist at Mayo Clinic, Rochester, Minn.,
and an associate editor of Neurology.
While more research is needed to figure out the depression-Alzheimer's link,
the results do suggest some practical advice, says Kennedy.
"If depression doubles or triples your risk, you want to make sure your
depression is treated as aggressively as possible," he says. Whether that
means medication, psychotherapy, exercise, or other means, he says, the point
is to treat the depression effectively.
While some older people think depression is a natural part of aging, it is
not, Kennedy says. Aggressive treatment of the depression is recommended, he
says, at any age.