Heart Ailments, Depression Linked
Mood Changes Often Tied to Cardiac Incidents, But Reasons Unclear

By David Brown
Washington Post Staff Writer
Thursday, June 22, 2006

Heart surgery can help bring on depression, and depression can worsen heart disease. But the relationship between the two conditions is complicated, murky and indirect, according to experts and numerous research studies.

The issue arose with the revelation that publisher and former diplomat Philip Merrill had apparently committed suicide while sailing alone on the Chesapeake Bay this month. It had been assumed that he had drowned after falling overboard.

When his body was found Monday with a gunshot wound in the head, Merrill's family noted in a statement that he had undergone "significant heart surgery over a year ago" and was taking "several medications" for his heart.

"Over the past four weeks," the statement said, "we observed that his spirit had dimmed. We spoke to him and consulted his physician about it. He was fatigued and unmotivated, a clear departure from his lifelong optimistic outlook and irrepressible spirit."

Details of the 72-year-old's medical history were not available.

Studies have found that 10 to 30 percent of people who have heart attacks or heart surgery develop depression afterward. Usually the mood disorder appears immediately after the illness or procedure, although occasionally it comes on months later.

"I would think it's not likely for an operation itself to be related to de novo depression 18 months after surgery," said Roy C. Ziegelstein, a cardiologist at Johns Hopkins University's Bayview Medical Center in Baltimore, who has studied the relationship between heart disease and mood changes.

Although some drugs taken by heart patients -- notably beta blockers -- occasionally cause mood changes, their contribution to post-operative depression is considered to be "very, very small," he said.

Suicide is not invariably linked to depression. "Psychological autopsies" of people who kill themselves suggest that 75 percent are depressed -- leaving a portion who are not.

"It is by no means a foregone conclusion that a person who has committed suicide was clinically depressed," said Klaus Ebmeier, a psychiatrist and suicide researcher at the University of Edinburgh in Scotland.

The exact links among heart disease, bypass surgery and mood are unknown. One of the few certainties is that depression after surgery is more common in people who had previous episodes of the disorder.

Some experts believe that alterations to the normal circulation and blood pressure during bypass surgery, or small clots that form during the operation, may damage the brain, at least temporarily.

A more likely explanation is that the onset of heart symptoms -- whether or not surgery is involved -- is often a patient's first serious brush with death.

For many, it requires redefining oneself, marks the start of lifelong medicine-taking and makes ordinary activity seem dangerous, at least for a while.

The disruptions caused even by successful treatment "in and of themselves can have significant effects on the way a person thinks, remembers, feels and acts," Ziegelstein said.

Heart disease in late middle age may itself presage a decline in mental function.

In a study published in 2001, researchers at Duke University described the experience of about 250 coronary bypass patients who underwent "neurocognitive" testing before their operations and at intervals afterward.

At the time of discharge from the hospital, 53 percent showed a decline in thinking ability. At six weeks, that number was down to 36 percent, and at six months it was 24 percent. But five years later, it was up to 45 percent.

More recent research is questioning the belief that bypass surgery causes subtle brain damage.

In a study last fall, neurologists at Johns Hopkins reported that people with heart disease who did not have surgery, and those who had surgery either on or off the heart-lung "pump" that many speculate is the cause of the problem, all had similar subtle declines in mental function in the year afterward, compared with people without heart disease.