A commonly prescribed anti-depressant may change brain structures in depressed and non-depressed individuals in very different ways, says a new study.
Although it is a common practice to prescribe antidepressants for various disorders besides depression, the findings of this study suggest that taking these medicines for treating disorders other than depression may expose us to unknown risks.
The antidepressant sertraline, marketed as Zoloft, significantly increased the volume of one brain region in depressed individuals but decreased the volume of two brain areas in non-depressed individuals.
"These observations are important for human health because Zoloft is widely prescribed for a number of disorders other than depression," said lead author of the study Carol Shively, professor at Wake Forest Baptist Medical Center in North Carolina, US.
Certain antidepressants, including Zoloft, are prescribed for a variety of disorders besides depression, including bulimia, hot flashes, obsessive-compulsive disorder, post-traumatic stress disorder, stroke recovery and sexual dysfunction, and there are no studies of the effects of these drugs on brain volumes in individuals not diagnosed with depression, the study said.
The study involved 41 middle-aged female monkeys who were divided into two groups balanced for body weight, body mass index and depressive behaviour.
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For the next 18 months, 21 monkeys received sertraline in daily doses comparable to those taken by humans while a group of 20 received a placebo.
MRI images taken at the end of the treatment phase revealed that in depressed participants the drug significantly increased the volume of one region of the brain, the anterior cingulate cortex, while decreasing the volume of this same region and the hippocampus in non-depressed participants.
Both of these areas are highly interconnected with other areas of the brain; are critical in a wide array of functions including memory, learning, spatial navigation, will, motivation and emotion; and are implicated in major depressive disorder.
The researchers said the findings need to be investigated further to see if these drugs produce similar effects in humans.
The study was published online in the journal Neuropharmacology.