MIddle-aged women who take antidepressants are at an increased risk of stroke, a major study has found.
A large study of women who have been through the menopause found those taking antidepressants were 45 per cent more likely to suffer a stroke than those of the same age not on the medicines.
The research also found that overall death rates were 32 per cent higher in women on the drugs.
Experts said patients would have to weigh the benefits of the drugs against the increased risk, adding that depression was a serious condition in itself that could prove fatal.
Antidepressants are one of the most commonly prescribed medicines in Britain and in 2008 there were 36 million prescriptions dispensed in England. It means around three million people were taking antidepressants in England last year.
The findings are from an analysis of the wider Women's Health Initiative Study and involved 136,000 women aged between 50 and 79.
Comparisons were made between the 5,500 women were had been prescribed antidepressants since being enrolled in the research and those who had not. There was no difference in the rates of heart attacks but those on antidepressants were 45 per cent more likely to suffer a stroke.
It is not known why there is a link and the researchers said they could not rule out that some of the effect may be due to the depression rather than just the drugs.
The drugs may affect how blood clots, the study said.
The findings were published in the journal Archives of Internal Medicine.
Lead author Dr Jordan Smoller, of the Massachusetts General Hospital, in Boston, America, wrote: "Although these results raise concerns about adverse effects of antidepressants, it is important to note that depression itself has been implicated as a risk factor for coronary heart disease, stroke, early death, and other adverse outcomes. In addition, inadequately treated depression is associated with substantial disability, impairments in quality of life, and health care costs.
"Nevertheless, our results suggest that physicians should be vigilant about controlling other modifiable cardiovascular risk factors in women taking antidepressants. Further research is needed to clarify the risk-benefit ratio of antidepressant use among older women."
The researchers said the risk of an individual woman suffering a stroke is low so even with the increase it remains relatively rare.
They said in the study the chance of an individual woman suffering a stroke in one year was 0.3 per cent for those not taking antidepressants and was 0.43 for those on the medicines.
They added that despite this, because antidepressants are prescribed in such large volumes there are important implications for public health.
Dr Jordan Smoller said: "While this study did find an association between antidepressants and cardiovascular events, additional research needs to be done to determine exactly what it signifies.
"Older women taking antidepressants, like everyone else, should also work on modifying their other risk factors for cardiovascular disease, such as maintaining a healthy weight and controlling cholesterol levels and blood pressure."
Joanne Murphy, Research Liaison Officer for The Stroke Association said: "This study seems to show a link between antidepressants and stroke; however the overall risk for women taking antidepressants is relatively small. More research needs to be done to determine the actual causes.
"We are already aware of links between depression and the risk of stroke and we are currently funding further studies to look into this.
"Everyone can help reduce their risk of stroke by making lifestyle changes, such as reducing their blood pressure, giving up smoking, reducing alcohol intake, improving their diet and getting plenty of exercise. Anyone who is at all concerned should consult their GP."