Reviewed by John M. Grohol, Psy.D. on August 12, 2011
Researchers following women participating in the Nurses’ Health Study discovered a history of depression was associated with a 29 percent increased risk of total stroke — even after considering other stroke risk factors.
Their findings are reported in Stroke: Journal of the American Heart Association.
Researchers also discovered women who use selective serotonin reuptake inhibitors (SSRI) class of anti-depressant medication, such as Prozac, Zoloft, and Celexa, had a 39 percent increased risk of stroke.
Anti-depressant medication use may be an indicator of depression severity, said Kathryn Rexrode, M.D., the study’s senior author. “I don’t think the medications themselves are the primary cause of the risk. This study does not suggest that people should stop their medications to reduce the risk of stroke.”
Researchers followed 80,574 women 54 to 79 years old in the Nurses’ Health Study from 2000-06 without a prior history of stroke. They assessed depressive symptoms multiple times with a Mental Health Index. Anti-depressant use was reported every two years beginning in 1996, and physicians diagnosed depression beginning in 2000.
Depression was defined as currently reporting or having a history of depression.
Researchers discovered 22 percent of the women were depressed at the beginning of the study. Over the next six years, 1,033 stroke cases were documented.
A comparison of women with depression to those without a history of depression, portrays key differences
Depressed women were slightly younger, had a higher body mass index, were more likely to be single and smoker, and were less physically active. They also had more coexisting conditions such as high blood pressure, heart disease and diabetes.
“Depression can prevent individuals from controlling other medical problems such as diabetes and hypertension, from taking medications regularly or pursuing other healthy lifestyle measures such as exercise,” said Rexrode.
“All these factors could contribute to increased risk.”
Depression may be associated with an increased risk of stroke through a variety of mechanisms. It may be linked to inflammation, which increases the risk of stroke as well as other conditions or underlying vascular disease in the brain, said An Pan, Ph.D., lead author of the study and a research scientist at the Harvard School of Public Health.
“Regardless of the mechanism, recognizing that depressed individuals may be at a higher risk of stroke may help the physician focus on not only treating the depression, but treating stroke risk factors such as hypertension, diabetes and elevated cholesterol as well as addressing lifestyle behaviors such as smoking and exercise.”
Researchers admit the study had limitations including use of a homogeneous sample as participants were predominantly white registered nurses.
“We cannot infer cause or fully exclude the possibility that the results could be explained by other unmeasured unknown factors,” Pan said.
“Although the underlying mechanisms remain unclear, recognizing that depressed women may be at a higher risk of stroke merits additional research into preventive strategies in this group.”
Source: American Heart Association