A new study suggests that men taking antidepressants may be at risk for atherosclerosis, which can increase the risk of a heart attack or stroke. The small study revealed that antidepressants were associated with about a 5 percent increase in the thickness of the large artery in the neck called the carotid artery, which carries blood to the brain, the researchers from Emory University said. Yet experts not involved with the study noted that it did not prove a cause-and-effect relationship between antidepressant use and heart trouble, and added that depression itself can increase the risk of cardiovascular problems.
Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles said, “Antidepressant medications may decrease cardiovascular risk by treating depression.” He added that the results are very preliminary and, “Patients should not be concerned or stop taking antidepressant medications on the basis of this study.”
The research team was led by Dr. Amit Shah, a cardiology fellow at Emory. Shah is a researcher working with Viola Vaccarino, chair of the Department of Epidemiology at Emory's Rollins School of Public Health. The team collected data on 513 middle-aged male twins who were part of the Vietnam Era Twin Registry. Sixteen percent of the men were taking antidepressants, and of these, 60 percent were taking selective serotonin reuptake inhibitors (SSRIs), such as Prozac, Lexapro and Zoloft. The others were taking older antidepressants. The researchers measured the thickness of the carotid artery - called carotid intima-media thickness. The study authors found that a twin taking an antidepressant had a greater intima-media thickness than a brother not taking the drugs. The finding held true, regardless of the antidepressant taken, the researchers said.
“There is a clear association between increased intima-media thickness and taking an antidepressant, and this trend is even stronger when we look at people who are on these medications and are more depressed,” Shah said in a news release from the American College of Cardiology. “Because we didn't see an association between depression itself and a thickening of the carotid artery, it strengthens the argument that it is more likely the antidepressants than the actual depression that could be behind the association,” he added. Researchers came to the conclusion after adjusting for age, diabetes, blood pressure, current or previous smoking, cholesterol and weight. Other factors weighed included depressive symptoms, history of major depression and heart disease, alcohol and coffee use, statin use, physical activity, education and employment, the researchers said.
They explain that since each additional year of life is associated with a small increase in intima-media thickness, a brother taking antidepressants is physically 4 years older than the brother not taking antidepressants, Shah's team contended. They also said that even a small increase in intima-media thickness can increase the risk of a heart attack or stroke by 1.8 percent.
The reason for this finding is still not clear. These drugs increase levels of the brain chemicals serotonin and norepinephrine, which are often low in depressed individuals. Shah said increased levels of these chemicals may cause blood vessels to tighten, and this may lead to reduced blood flow to organs and higher blood pressure, which is a risk factor for atherosclerosis.
Dr. Dominique L. Musselman, an associate professor of clinical psychiatry at the University of Miami Miller School of Medicine, an independent observer said that the association between antidepressant use and atherosclerosis was not a cause-and-effect relationship. He said, “This finding is somewhat counterintuitive since it is well known that SSRIs enhance a tendency to bleed.” He called for more studies. Musselman also strongly advises patients not to stop taking antidepressants based on this study. “This is an important finding that needs to be replicated,” she added.
The data is being presented Tuesday, April 5 at the American College of Cardiology meeting in New Orleans. The study was funded by the U.S. National Institutes of Health.