A commonly prescribed antidepressant
caused up to a six-fold increase in atherosclerosis plaque in the coronary
arteries of non-human primates, according to a study by researchers at Wake
Forest Baptist Medical Center. Coronary artery atherosclerosis is the primary
cause of heart attacks.
The study is published in the current online issue of the
journal Psychosomatic Medicine.
“The medical community has known for years that
depression is closely associated with heart disease, but we didn’t know if
treating it would reduce the heart disease risk,” said Carol Shively, Ph.D.,
professor of pathology/comparative medicine at Wake Forest Baptist and lead author
of the study.
In the study, 42 middle-aged female monkeys were fed a Western-like
diet containing fat and cholesterol for 18 months. During this pre-treatment
phase, depressive behavior in the animals was recorded.
Female animals were chosen for the study because coronary
heart disease is the leading cause of death in women in the United States, and
depressive disorders are twice as likely in women as in men.
The animals were then randomly assigned to receive a
commonly prescribed antidepressant, a selective serotonin reuptake inhibitor
(SSRI) marketed under the brand name Zoloft, or a placebo once a day for 18
months. The antidepressant was given in a dose comparable to that given to patients.
The monkeys that received the SSRI developed three times
the amount of atherosclerosis in their coronary arteries as monkeys given the
placebo. In the depressed animals, the amount was even higher – almost six
times greater in the SSRI-treated animals than in those given the placebo.
“Our findings suggest that long-term treatment with this
drug promotes coronary artery atherosclerosis in non-human primates,” Shively
said. “This may be clinically significant for people because almost a quarter
of middle-aged women in the United States take antidepressants, the most
prescribed of which are SSRIs.”
Shively added that although more research is needed,
doctors may want to keep these findings in mind when they are prescribing
antidepressants. Previous studies have shown that exercise and counseling may
be as effective as SSRIs in treating depression for many people.
The study was funded by the National Institutes of Health
Co-authors of the study are Thomas C. Register, Ph.D.,
Susan E. Appt, D.V.M., and Thomas B. Clarkson, D.V.M. of Wake Forest Baptist.