New Trial Should Lead to Better Understanding of Why Exercise is an Effective Treatment for Depression
DURHAM, N.C. - The Duke University Medical Center
researchers who found evidence that exercise can be an
effective treatment for major depression are
embarking on a larger trial they believe will answer some of
the remaining questions posed by their earlier results.
The new trial, which is being funded by a $3 million grant
from the National Institute of Mental Health, is designed to
further refine which depressed patients can benefit
from exercise and determine why exercise appears to be
Additionally, the study will measure the effect of exercise
on a phenomenon known as vascular depression, a form of
depression that appears linked to actual
abnormalities in blood vessels of the brain, and not brain
The previous Duke studies, led by psychologist James
Blumenthal, found that exercise was just as effective as the
most common anti-depressive medication in reducing
the symptoms of major depression.
"This new trial is intended to answer some of the 'whys'
posed by those original studies," Blumenthal explained. "We are
very interested in evaluating behavioral,
non-pharmacologic approaches to treating depression. Because up
to one-third of depressed patients may not respond to drug
therapy, and those who do take drugs may
complain of side effects, it is important to find other
Over the next five years, the researchers plan to enroll 216
volunteers, half of whom will be assigned randomly to the drug
arm of the trial and half to the exercise arm.
The drug to be used is sertraline (trade name Zoloft), a member
of a class of commonly used anti-depressants known as selective
serotonin reuptake inhibitors, and the
same drug used in the earlier trials.
Unlike the earlier trials, the new trial will have a
placebo, or ineffective sugar pill, arm. Also unlike the
earlier trials, the exercise arm will be divided as well - half
patients will do their exercises in the supportive atmosphere
of the Duke Center for Living (CFL), while the other half will
perform the same exercise regimens at home.
Moderate exercise will be performed three times a week in both
"One of the questions raised by previous studies was whether
the supportive atmosphere of exercising in a group, with other
similar patients and trainers, had any effect
on relieving the depression," Blumenthal said. "At the
completion of this trial, we should be better able to determine
how much of the benefit was derived from exercise
and how much, if any, came from the supportive atmosphere."
A new focus in this trial examines vascular depression, a
form of the disorder that is not yet widely recognized, but is
being actively studied by investigators at Duke and
Cornell. "Vascular depression is a recently identified clinical
type of depression," said Dr. Murali Doraiswamy, Duke
psychiatrist and co-investigator of the trial. "We
know, for example, that depression occurs at high rates in
older patients who have other vascular diseases, such as heart
disease, diabetes or stroke.
"We also know in the setting of these kinds of diseases that
patients have compromised cerebrovascular function, apparently
caused by tiny little strokes deep in the
brain," he said. "There is a growing consensus that these
changes may actually be mediating the high rates of depression
in these patients."
Doraiswamy said that while depression is clearly associated
with imbalances of key chemicals in the brain, there are likely
many different causes behind these brain
chemical changes. Duke studies have shown that up to one-third
of the cases of depression in patients over the age of 65 may
be due to this vascular form of the
"We do not yet know the most optimal strategy to treat
depression in such patients," Doraiswamy said. "Some data
suggest that people with vascular lesions often do not
respond as well to antidepressants.
"With this trial, we hope to determine if exercise improves
blood flow in the brain and has a positive effect on relieving
the depression," Doraiswamy continued.
"Exercise would be a very attractive option for these patients.
Since we know that exercise helps to control risk factors in
cardiovascular disease, it seems logical to
assume that it could be an ideal treatment for patients with
The treatment will last for four months, and patients will
be followed up six months and one year later.
In order to be eligible for the trial, participants must be
over the age of 54, sedentary and suffer from clinically
diagnosed major depression. Symptoms include depressed
mood or loss of interest or pleasure, combined with at least
four of the following: sleep disturbances, weight loss, changes
in appetite, psychomotor agitation, feelings of
worthlessness or excessive guilt, impaired cognition or
concentration, and recurrent thoughts of death.