Relatively healthy women with severe depression are at increased risk for heart problems, including sudden cardiac death and fatal heart disease, a new study finds.
But even more startling is that the researchers suggest that some of the antidepressants used to treat these women might play a role in their increased heart risk.
Doctors from Columbia University in New York and the University of California at San Diego analyzed information provided by 63,469 women participating in the ongoing Nurses Health Study. Overall, they found that women with depression were more than twice as likely to experience sudden cardiac death, and 37 percent more likely to die of heart disease, compared to women without depression.
But perhaps more surprising was that an increased risk of heart trouble in these women appeared to have less to do with the symptoms of depression -- and more to do with the use of antidepressants.
The researchers cautioned in their report that women with depression should not discontinue use of antidepressants out of fear regarding the increased heart risk associated with these drugs.
"We want to emphasize that we're not advising anyone to stop antidepressant use based on this study," said lead study investigator Dr. William Whang, assistant professor of clinical medicine at Columbia University. "That finding is worth exploring more but certainly there's no way to say anything about causality from this study."
Still, experts admit these findings are compelling enough to justify further research into the possible cardiovascular risks associated with the use of antidepressants.
"The data are strong enough to indicate that those who receive antidepressants are at greater risk [of heart trouble]," said Dr. Andrew Leuchter, professor in the department of psychiatry and director of the Laboratory of Brain, Behavior and Pharmacology at the University of California at Los Angeles. "This is just a correlation, however, and the data do not indicate anything about the cause. ... I think that there should be more study of the question."
Antidepressant Links Still Preliminary, Researchers Warn
Antidepressants are among the most commonly prescribed drugs in the United States, according to a report by the Centers for Disease Control and Prevention (CDC). The report found that out of 2.4 billion prescriptions American doctors wrote in 2005, about 118 million were for antidepressants.
The report also showed these numbers are on the rise: Adult use of antidepressants almost tripled between the period from 1988-1994 to the period from 1999-2000.
Antidepressants have been linked to a variety of side effects, from the more moderate, such as nausea, diarrhea, headaches, and loss of sex drive -- to the more serious, including increased risk for suicidal thoughts and suicide.
Adding heart risks to this list for women would indeed be a matter of concern, as heart disease is already the top cause of death among American women.
But experts maintain that the link found between antidepressants and heart risk in this study are preliminary and must be confirmed by future studies, as it remains unclear whether the antidepressants themselves increase the risk for sudden cardiac death or whether they are simply a marker for severe depression.
"I think this study cannot be interpreted as showing anything other than that it confirms all the other research documenting impact of depression on [heart] risk," said Dr. Redford Williams, head of the department of psychiatry and behavioral sciences at Duke University.
Williams added that, although an older form of antidepressants, called tricyclic antidepressants, have been shown in past studies to raise one's risk for heart attack, these drugs have been largely replaced by a newer class of antidepressants, called selective serotonin reuptake inhibitors, or SSRIs.
Past research on SSRIs has shown that the risk of cardiovascular side effects is quite low. In fact, a study published in the November 2008 issue of the Archives of Internal Medicine found that depression, not the use of antidepressants, was associated with a 33 percent increased mortality risk in heart patients.
"Most of these women were treated with SSRIs, I would suspect, and they are pretty free of cardiac effects," Williams said. "So my bet is that the finding means that women with more severe depression -- documented by needing [an] antidepressant [prescription] -- are at higher risk for [sudden cardiac death]."
Depressive Behaviors, Not Drugs, May Still Be to Blame
But there's no need for depressed women to think they are doomed to an early cardiac death. Whang also suggested that depressive behaviors, rather than the actual depression itself, could be responsible for a great deal of the increase in heart risk for severely depressed women.
"We found that women with more depressive symptoms were more likely to smoke, less likely to be physically active, and had higher rates of obesity," Whang said.
For this reason, Whang suggests that severely depressed patients seek drug treatment as well as try to manage their cardiac risk factors, including smoking, eating healthy, and exercising regularly.
Most importantly, experts urged that women who are severely depressed should not discontinue the use of their antidepressant out of fear that the drug might raise their heart risk.
"The downside of this kind of story is that some people will stop taking their antidepressants because of the possible cardiac risk, which possibly is exactly the wrong thing to do," Leuchter said.
Instead, experts urged that women focus on eating well, exercising regularly, and trying to manage their anger and stress levels in order to bring their overall heart risk down.