Apr 4, 2011 12:37 GMT  ·  By

Investigators say that some of the most widely-used drugs against depression may also contribute to a thickening of the arteries in patients taking them. Some of these forms of medication include a class of compounds known as selective serotonin reuptake inhibitors (SSRI).

Past studies have already determined that the mental condition itself is a risk factor for the development of heart disease and related conditions. The new study seems to suggest that the combined effects of depression and anti-depression medication may be too much for blood vessels.

Generally, arteries thicken with age, and are therefore more common in seniors than in adults. But experts discovered in the new study that the arteries of those who took drugs against depression looked as if they were around four years older than they actually were.

The carotid arteries were the target of this investigation, and they were determined to be the most affected. This study was conducted on 513 male twins at middle age, all of which fought in Vietnam.

According to Amit Shah, MD, the reason twins were used is because, though they are identical genetically, they are also prone to experience other influences, such as smoking, lifestyle choices, diets and so on, PsychCentral reports.

“So studying them is a good way to distill out the effects of genetics,” explains Amit Shah, MD, the first author of the new research. The expert is also a cardiology fellow at Emory University School of Medicine.

Emory experts used ultrasound measurements to analyze the thickness of carotid arteries in all test participants. About 59 twin pairs featured a member who took antidepressants, and one who did not.

The study revealed that the brother who took antidepressants was always more likely to have thicker arteries than the one who did not. The correlation held true even after other risk factors were accounted for, and regardless of previous heart attack or stroke events.

“One of the strongest and best-studied factors that thickens someone’s arteries is age, and that happens at around 10 microns per year. In our study, users of antidepressants see an average 40 micron increase in IMT, so their carotid arteries are in effect four years older,” Shah adds.

“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 circulatory system. The body often compensates over time for drugs’ immediate effects,” the expert explains.

One of the most commonly-used and prescribed selective serotonin reuptake inhibitor is fluoxetine, known under the brand name Prozac. There are also other types of drugs that affect serotonin, some of them indirectly.

“Antidepressants have a clinical benefit that has been established, so nobody taking these medications should stop based only on these results,” Shah adds.

“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,” the expert concludes.