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.
The findings also held true after compensating for such factors as 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.
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.
It's not clear why there might be an association between antidepressant use and heart disease, the study authors noted. 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.
All rights reserved