MONDAY, March 9 (HealthDay News) -- Women who use antidepressants appear to be at heightened risk for sudden cardiac death, although the exact nature of the link remains unclear, researchers say.

The finding doesn't necessarily mean that antidepressant drugs are dangerous, the researchers said.

"We suspect that their use is a marker for people with worse depression," explained study lead author Dr. William Whang, an assistant professor of clinical medicine at Columbia University Medical Center in New York City. "The elevated risk seems more specific for antidepressant use, but that use may well be a marker of more severe symptoms."

The link between depression and heart trouble is more likely physical than psychological, Whang added. "We found that women who had worse depressive symptoms had higher rates of risk factors such as hypertension, diabetes and smoking," he said.

Women with clinical depression were more than twice as likely to experience sudden cardiac death, the report said.

The findings were published in the March 17 issue of the Journal of the American College of Cardiology.

The researchers relied on data on more than 63,000 American women in the Nurses Health Study. And while the research team did find a link between depression and heart risk, the incidence of sudden cardiac death was associated more strongly with the use of antidepressant drugs than with symptoms of depression.

Antidepressant drug use was not associated with a higher risk of heart attacks or overall fatal heart disease, just with sudden cardiac death, the study found.

Previous studies have shown a link between depression and higher mortality for people who already had heart disease, Whang said. "But this was a group of women without heart disease, and that makes it different," he noted.