Are Mood Disorders a Stroke Risk Factor?

Abstract

See related article, pages 16–21 A growing body of evidence suggests that biological mechanisms underlie a bidirectional link between depression and many neurological illnesses, and that mood disorders can affect the course of the diseases.1 Depression commonly occurs after a stroke, with an estimated prevalence as high as 30% in the first year after the event.2 It is well known that poststroke depression affects quality of life, functional recovery, cognitive function and health care use in stroke survivors.3 Inversely, does any association exist between a history of a previous affective disorder and future risk of cardiovascular events? Recent prospective studies have shown an association between depression and incidence of hypertension,4,5 coronary heart disease,6,7 and cardiovascular mortality.8–11 In the Multiple Risk Factor Intervention Trial, 12 866 men were followed for 18 years; those with greater depressive symptoms, as measured by the Center for Epidemiologic Studies Depression Scale (CES-D), were associated with a significant higher risk of cardiovascular mortality (hazard ratio=1.21; 95% CI, 1.03 to 1.41; P <0.05) and stroke mortality (hazard ratio= 2.03; 95% CI, 1.20 to 3.44; P <0.01).12 The NHANES I Epidemiologic Study13 showed that individuals reporting 5 or more symptoms of depression at baseline were 50% more likely to die of a stroke-related cause during a 29-year follow-up. The Baltimore Epidemiologic Catchment Area Study showed that individuals with a history of depressive disorder, measured with the diagnostic interview schedule, were 2.6 times more likely to report stroke.14 Depressive symptoms, measured by the Zung Self-rating Depression Scale, were also associated with an increased incidence of ischemic stroke in a Japanese 10-year follow study.15 Self-reported depression scores significantly predicted stroke in an Australian cohort of people …