LOS ANGELES, April 2 (Xinhua) -- People taking antidepressants may be more likely to develop thicker arteries which may raise the risk of heart disease and stroke, a new study suggests.
Depression can heighten the risk for heart disease, but the effect of antidepressant use is separate and independent from depression itself, according to the study make public by the American Association for the Advancement of Science (AAAS) on Saturday.
The data suggest that antidepressants may combine with depression for a negative effect on blood vessels, said study first author Amit Shah, MD, a cardiology fellow at Emory University School of Medicine.
Study findings will be presented on April 5 at the American College of Cardiology meeting in New Orleans, according to the AAAS.
The study included 513 middle-aged male twins who both served in the U.S. military during the Vietnam War. Twins are genetically the same but may be different when it comes to other risk factors such as diet, smoking and exercise, so studying them is a good way to distill out the effects of genetics.
Researchers measured carotid intima-media thickness - the thickness of the lining of the main arteries in the neck -- by ultrasound. Among the 59 pairs of twins where only one brother took antidepressants, the one taking the drugs tended to have higher carotid intima-media thickness (IMT), even when standard heart disease risk factors were taken into account.
The effect was seen both in twins with or without a previous heart attack or stroke. A higher level of depressive symptoms was associated with higher IMT only in those taking antidepressants.
One of the strongest and best-studied factors that thickens someone's arteries is age, and that happens at around 10 microns per year, Shah said. In our study, users of antidepressants see an average 40 micron increase in IMT, so their carotid arteries are in effect four years older.
Antidepressants' effects on blood vessels may come from changes in serotonin, a chemical that helps some brain cells communicate but also functions outside the brain, Shah said.
I think we have to keep an open mind about the effects of antidepressants on neurochemicals like serotonin in places outside the brain, such as the vasculature. The body often compensates over time for drugs' immediate effects, Shah said. Antidepressants have a clinical benefit that has been established, so nobody taking these medications should stop based only on these results. This isn 't the kind of study where we can know cause and effect, let alone mechanism, and we need to see whether this holds up in other population groups.