Depression may play a role in stroke risk

Feelings of hopelessness and other signs of major depression markedly raise a person’s likelihood of suffering a stroke, according to a new analysis of data from a long-term study.

Over an average follow-up period of 16 years, the initial presence of symptoms of major depression raised the relative risk of incurring a stroke about as much as did a 40-point increase in systolic blood pressure, say epidemiologists Bruce S. Jonas and Michael E. Mussolino, both of the National Center for Health Statistics.

Severe depressive symptoms posed a greater statistical risk for suffering a stroke than did 13 other factors, including having a high blood concentration of cholesterol or high systolic blood pressure, smoking cigarettes, drinking alcohol, shunning exercise, or being overweight, black, diabetic, or elderly. Being male was the only risk factor for stroke that exhibited about the same power as depression.

The relative risk of stroke rose less steeply, but still substantially, among people who cited moderate depressive symptoms, Jonas and Mussolino report in the July/August Psychosomatic Medicine.

The researchers obtained data from a nationally representative sample of 6,095 individuals who took part in a study of health and nutrition. Participants, ages 25 to 74 years, first completed a medical examination and questionnaires on various topics, including mood. Four items assessed the extent to which they felt sad, downhearted, low in spirits, and hopeless to the point of wanting to give up.

Researchers then performed three follow-up surveys and reviews of medical and hospital records over a span of as many as 22 years.

Depression’s association with strokes held for men and women, whites and blacks, and younger and older people, Jonas and Mussolino say.

It’s unlikely that vascular disease first led to depression and then to stroke, they add. The findings remained nearly as strong after excluding either volunteers who suffered a stroke in the first 10 years of the study or those who began the study with recognized heart disease or diabetes.

Earlier prospective studies of depression and strokes have yielded inconsistent results. Other data link depression to an elevated risk of hypertension and heart disease (SN: 7/31/93, p. 79).

Depression alters brain, endocrine, and immune activity. However, it’s unclear what specific physiological changes resulting from depression might promote strokes, Jonas and Mussolino say. In some cases, depression may cause hypertension, which subsequently leads to strokes, they suggest.

The new evidence that preexisting depression markedly raises one’s chances of suffering a stroke “is likely to be important for public health,” comments psychiatrist Lewis L. Judd of the University of California, San Diego, in the same journal.

“Effective treatment of depressive symptoms may reduce the risk of stroke, but this intriguing suggestion awaits prospective and controlled investigation,” he asserts.

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.