Heart Disease & Depression - A Two-Way Street?

By Michael Craig Miller, M.D.
Content provided by the Faculty of the Harvard Medical School

When a cardiologist (heart doctor) asks how a patient is feeling, the question usually refers to the body. But he or she should ask about moods and emotions, too. The answer can offer important information about a person's general and cardiovascular health.

Mental and physical health were once considered separate entities. Now we know they are profoundly connected. The relationship between depression and heart disease is a good example:

  • People who are depressed are more likely to develop heart disease or have a heart attack than people who aren't depressed.

  • People who have had a heart attack or live with heart failure or another heart or blood vessel condition are more likely to become depressed than people without these diseases.

Evidence is building that when doctors identify and treat depression, it is good for the heart. In September 2008, the American Heart Association (AHA) issued guidelines to raise awareness of the hazardous link between depression and heart disease.

Depression: Not a "Normal" Response to Heart Disease

People being treated for heart disease — particularly if it is severe — may have difficulty recognizing their own depression. They may accept their sadness as a normal reaction to having an illness that can take the pleasures our of life or, even worse, raise the threat of sudden death. Doctors may easily attribute a patient's reduced activity level, diminished zest for life, or changes in sleep and appetite to "normal" reactions to heart disease.

Many symptoms of heart disease mimic symptoms of depression. Thus, more and more cardiologists and primary care doctors are using formal questionnaires to screen patients for depression. Such tools help doctors find out about eating and sleeping habits, energy level, concentration and the ability to take pleasure from daily activities.

The Sad Heart

Depression is hard on the heart and the arteries that carry blood to it. Among healthy individuals, depression doubles the risk of sudden cardiac death and increases the chances of having a heart attack or stroke. The risk is even greater in people who already have a heart condition.

What's the connection? Depression is associated with physical changes that can pave the way for heart trouble.

  • Depression has a negative effect on two important hormone systems: the hypothalamic-pituitary-adrenal (HPA) axis and the renin-angiotensin-aldosterone system. They both influence heart and blood vessel health.

  • Scientists have found that signaling molecules called pro-inflammatory cytokines are activated in people with depression. These cytokines appear to promote atherosclerosis and the rupture of cholesterol-filled plaque, which can block blood flow to heart muscle and cause death.

  • Depression can change heart rate and rhythm in unhealthy ways.

  • Depression also activates platelets. (Platelets are small cell fragments in the blood stream that are essential for blood clotting.) Platelets are sometimes described as becoming "stickier" because they are more likely to clump and form clots in the bloodstream.

Behavioral changes brought on by depression may be just as important. A report from the ongoing Heart and Soul Study cited physical inactivity and behavioral factors as major contributors to the connection between depression and heart disease.

People who are depressed find it difficult to:

  • Exercise

  • Pay attention to what they are eating

  • Take medicines needed to protect the heart

They also tend to withdraw from family, friends and other social interactions. This can further boost the risk of heart disease.

Treating Depression And Heart Disease Together

Medications and psychotherapy and the mainstays for treating depression. They are generally effective for patients with heart disease. But other treatments deserve special mention. One of them is exercise.

Medications

Your Guide to Heart Disease


Did You Know?

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When the heart muscle's blood supply is cut off, heart muscle cells fail to get enough oxygen and begin to die. What is this called?