How is depression linked to heart disease?

It has been shown that as many as 30-40% of cardiac patients experience clinically important depressive symptoms. Major depressive disorder is present in as many as 20% of patients with cardiovascular disease and is associated with adverse cardiovascular outcomes, even after controlling for other risk factors.

Depression is related to the onset of cardiac disease, and is associated with higher medical costs, reduction in patients' quality of life and triple the risk of non-adherence with medical treatment regimens. In fact, cardiovascular prognosis is linked to the severity of depressive symptoms. Risk increases along with symptom severity whether or not the patient meets diagnostic criteria for a depressive disorder.

Depression reduces the chances of successful modification of cardiac risk factors and participation in cardiac rehabilitation, and is associated with higher health care utilization and costs and greatly reduced quality of life.

The relationship between depression and heart disease is a two-way street. A review article reported that depression roughly doubles your risk of developing coronary artery disease. Other studies show that people who already have heart disease are three times as likely to be depressed as other people. As many as one in five heart attack survivors develops depression. And depression is an independent risk factor for a subsequent heart attack in people who've already had one. This may be in part because people who are depressed are less likely to take proper care of themselves -- by quitting smoking, taking medications, or exercising -- even after a heart attack.