Depression may increase the chances of women having a stroke.
A large six-year study found that a history of depression increased the risk of stroke in post-menopausal women by 29pc.
Women who used common antidepressants such as Prozac had a 39pc higher risk. But scientists said they did not believe the drugs were to blame and urged women not to stop taking their medication.
The 80,574 women were all participants in the Nurses' Health Study, a major US research project focusing on factors influencing the long-term health of nurses.
All had no prior history of stroke and were aged between 54 and 79.
Anti-depressant use was reported every two years beginning in 1996. For six years from 2000, a record was kept of the number of strokes occurring among the women.
Compared with women without a history of depression, depressed individuals were more likely to be single, smokers and less physically active.
The research is published in the American Heart Association journal Stroke.
"Depression can prevent individuals from controlling other medical problems such as diabetes and hypertension (high blood pressure), from taking medications regularly or pursuing other healthy lifestyle measures such as exercise," said study leader Dr Kathryn Rextrode, from Brigham and Women's Hospital in Boston, US.
"All these factors could contribute to increased risk."