Reporting in the Journal of the American Medical Association, researchers at the Harvard School of Public Health and Brigham and Women’s Hospital found that depression increased the risk of stroke by 45% and the risk of dying from a stroke by 55%.
In the current study, first author An Pan, a research fellow in the department of nutrition at the Harvard School of Public Health, searched the medical literature for all studies involving depression and stroke. Among these, he found 28 trials involving more than 317,000 participants who were followed up for stroke incidence for anywhere from two to 29 years.
The study found that depression contributed to the risk of stroke and dying from stroke almost as much as well-established risk factors such as smoking and obesity.
The reason for the connection may have to do with hormones in the nervous system that are affected by depression and can increase stroke risk. Inflammation, another process common to both depression and stroke, may also play a role. And lifestyle factors that are typically associated with depression, such as smoking, eating an unhealthy diet and being overweight, may help explain the link as well.
Another possible explanation could involve the treatment for depression, says Pan. Antidepressant medications may increase stroke risk in a number of ways, including the chemical pathways they affect in the body and their side effect of weight gain, which can in turn raise stroke risk. But, Pan stresses, “There is a lot of information we don’t know, so we don’t want to send the wrong message to patients or doctors that they should stop their anti-depressant medications.”
The study results suggest that when doctors are screening for stroke, they should not only consider traditional risk factors such as heart disease and diabetes, but also ask about their patients’ mental state.