Severe depression may silently break a seemingly healthy woman's heart.
Doctors have long known that depression is common after a heart attack or stroke, and worsensthose people's outcomes. Monday, Columbia University researchers reported new evidence that depression can lead to heart disease in the first place.
The scientists tracked 63,000 women from the long-running Nurses' Health Study between 1992and 2004. None had signs of heart disease when the study began, but nearly 8 percent had evidenceof serious depression.
The depressed women were more than twice as likely to experience sudden cardiac death -- deathtypically caused by an irregular heartbeat, concluded the 12-year study, published Monday in theJournal of the American College of Cardiology. They also had a smaller increased risk of death fromother forms of heart disease.
The big surprise: Sudden cardiac death seemed more closely linked with antidepressant use thanwith the depression symptoms the women reported.
That might simply mean that women who used antidepressants were, appropriately, the mostseriously depressed, cautioned lead researcher Dr. William Whang. But he said the finding meritedmore research.
Studies of the newer antidepressants most often used today so far haven't signaled a risk ofirregular heartbeat, and some even have suggested protection, noted Dr. Redford Williams of DukeUniversity, a specialist in how psychosocial factors affect health.
The drug question aside, Williams said the work adds to growing evidence that depression is anindependent risk factor for heart disease -- on top of the classic risks of high blood pressure,diabetes, high cholesterol and smoking.
The predominantly white Nurses' Health Study may underestimate it, Williams said. "If anything,the impact in African-American women is probably greater," he said, adding that it's time for thenext step: A study testing whether properly treating depression lowers the risk.
Why might depression have that effect? The study found that the more severe the women'sreported depression symptoms, the more likely she was to have traditional heart risk factors. Also,stresses like depression have been linked to such physical effects as a higher resting heart rate.
Perhaps a more straightforward reason: Depression can make people do a worse job taking care ofthemselves. Indeed, the American Heart Association last year recommended that everyone whoalready has heart disease be regularly screened for depression -- because depressed patients mayskip their medications, sit indoors instead of exercising, and eat particularly poorly.