Washington University. US: Depression and behavioral changes may occur before memory declines in
people who will go on to develop Alzheimer’s disease, according to new
research at Washington University School of Medicine in St. Louis.
Researchers have known that many people with Alzheimer’s experience
depression, irritability, apathy and appetite loss but had not
recognized how early these symptoms appear. Pinpointing the origins of
these symptoms could be important to fully understanding Alzheimer’s
effects on the brain and finding ways to counteract them.
“There has been conflicting evidence on the relationship between
Alzheimer’s and depression,” said senior author Catherine M. Roe, PhD,
assistant professor of neurology. “We still don’t know whether some of
these symptoms, such as irritability and sadness, are due to people
realizing on some level that they are having problems with memory and
thinking, or whether these symptoms are caused directly by Alzheimer’s
effects on the brain.”
The study appears Jan. 14 in Neurology.
Roe and her colleagues at the university’s Charles F. and Joanne
Knight Alzheimer’s Disease Research Center analyzed data on 2,416 people
ages 50 and older. Scientists regularly evaluated the participants for
up to seven years, including how they performed in extensive tests of
mental function and psychological health.
All of the participants were cognitively normal at the start, but
over the course of the study, 1,218 of them developed dementia.
Those who developed dementia during the study were more likely to
have mood and behavioral changesfirst. For example, four years into the
study, 30 percent of those who would go on to develop dementia had
developed depression. In comparison, after the same period of time, only
15 percent of those who did not develop dementia during the study had
become depressed. In addition, those who would go on to develop dementia
were more than 12 times as likely to have delusions than those who did
not develop dementia.
Alzheimer’s researchers have been working to develop markers they can
use to diagnose disease before the onset of dementia. The hope is to
begin treating the condition before patients develop dementia.
However, Roe cautioned that the mood changes will not work well as
markers in this regard until researchers better understand how these
changes are connected to the disease.
The research was funded by the Longer Life Foundation; the National
Institute on Aging of the National Institutes of Health (NIH), grants
P50 AG005681, P01 AG003991, P01 AG026276, U01 AG016976; Fred Simmons and
Olga Mohan; the Farrell Family Research Fund; and the Charles and
Joanne Knight Alzheimer’s Research Initiative of the Washington
University Knight Alzheimer’s Disease Research Center.
Masters MC, Morris JC, Roe CM. “Noncognitive” symptoms of early Alzheimer disease. Neurology. Jan. 14, 2015.