Depression is often associated with medical comorbidity. New research quantifies patterns of mood disorder in illnesses such as cardiovascular disease and diabetes, evaluates the prognostic significance of mood symptoms, and seeks to identify common mechanisms for both mood and medical disease. This review provides recent findings on comorbidity, summarizes mechanistic hypotheses, and outlines developments in treatment and services.
Depression occurs in up to one-quarter of patients with cardiovascular disease and diabetes. Depressed patients with heart disease have poorer medical outcomes including increased risk of reinfarction and all-cause mortality. Patients with diabetes and depression have poorer glycemic control, more diabetes symptoms, and greater all-cause mortality. Depression is associated with both biological (hypothalamic-pituitary-adrenal axis dysregulation) and psychosocial processes (adherence, poorer diet, and exercise) that may mediate adverse medical outcomes. Antidepressant treatments are effective in treating depression in medically ill patients, but their impact on medical outcomes remains to be quantified.
Depression, cardiovascular disease, and diabetes are among the most common chronic illnesses affecting an aging population. Depression is treatable in patients with medical illnesses, and collaborative care models can yield better detection and depression treatment in primary care settings in which most patients with depression are seen.