2011 ACC: Antidepressants May Age Blood Vessels, Study of Twins Finds

NEW ORLEANS — April 2, 2011 — Taking antidepressants may have an adverse effect on blood vessels, researchers report in a unique “twin study of middle-aged men” today in a news conference at the American College of Cardiology’s (ACC) 60th Annual Scientific Sessions and ACC.i2 Summit.

“The trend is even stronger when we look at people who are on these medications and who are also depressed,” reported lead investigator, Amit Shah, M.D., cardiology fellow, Emory University, Atlanta, Ga., who reported the study findings: Association of Antidepressant Medications with Carotid Intima Media Thickness in Middle Aged Veteran Twins.

“Even when looking within 59 of the male twin pairs (mean age 55 years), where one brother is taking an antidepressant and the other is not, the brother taking the medication had a 41 um thicker inner lining of the carotid artery (p=0.01, adjusted.), making him four years older, in terms of artery health.”

“The take home message for physicians is that they should consider the risk and benefits,” Dr. Shah said in a news conference.

Population studies have shown a direct correlation with antidepressants and heart attack risk: Each 10 um increase translates to a 1.8 increased CVD risk. “While previous studies have shown that people with depression have a heightened risk of heart disease, surprisingly, neither depression nor post traumatic stress disorder (PTSD) was a significant predictor of IMT,” Dr. Shah said.

Antidepressant use was 16 %, and most study participants (60%) were taking selective serotonin reuptake inhibitors (SSRIs). When comparing SSRIs to non SSRIs, researchers found an increase in IMT regardless of the type, suggesting that it is “the antidepressants rather than the depression” that is linked to increase in carotid intima-media thickness.

The study included 513 male twins, mean age 55, from the Vietnam Era Twin Registry, who had IMT via B mode ultrasound tests.

Antidepressant use was associated with a 37 micron (um) increase in carotid IMT (about a 5% increase from the mean IMT value of 762 um (p=0.006), controlling for CVD major risk factors, such as age, diabetes, blood pressure and smoking.

In addition, the study controlled for other factors, such as medication and socioeconomic factors, statin use, physical activity, employment status and education -- factors that can also “muddy the findings,” Dr. Shah observed.

Researchers cautioned that the study is observational and cannot prove causality, and they recommend additional researcher to determine if “antidepressants themselves increase IMT in the carotid arteries, or if there are other factors that mediate this effect.”

Serotonin may be one mechanism “at work” and thus could explain the study’s findings.

The connections between antidepressants and heart health is not “fully understood.”

“These medications increase levels of certain chemical messengers, such as serotonin and norepinephrine, which are often low in depression and may have unhealthy effects on the blood vessels, decreasing blood flow,” Dr. Shah said.