Depression and cardiovascular disease: Increasing evidence of a connection

Cardiovascular disease (CVD) and major depression co-occur with far greater frequency than is generally recognized. Failure to diagnose major depression in patients with CVD may have a substantial detrimental effect on outcomes, given evidence from numerous studies suggesting that depression is an independent risk factor not only for the development of CVD, but also for death following myocardial infarction (MI). Extensive psychobiological research has revealed several pathophysiologic mechanisms that may contribute to the apparent vulnerability of depressed patients to CVD and to post-MI mortality. These mechanisms include increased sympathetic nervous system activity, reduced heart rate variability, ventricular instability and myocardial ischemia in response to emotional stress, and altered platelet function. Effective treatment of depression alleviates depressive symptoms, improves quality of life, and is associated with normalization of many pathophysiologic alterations associated with major depression. Certain newer antidepressant agents appear to offer increased safety in patients with CVD. Future investigations will determine whether antidepressant treatment of the approximately 18%-25% of post-MI patients who fulfill diagnostic criteria for major depression has a significant impact on cardiovascular morbidity and mortality.