Bill Valvo could sense that something was going very wrong with his health. He had worked for a software-development company in Fairfax, Va., for 10 years following a 22-year hitch with the Air Force, and the pressure was finally too much. "I left to start my own business," says Valvo, now 55, "but I could feel that all the stress was having physiological effects." Sure enough, he was diagnosed with coronary-artery disease and underwent bypass surgery in 1999. But after the operation, he spiraled into a severe depression, which would recede and then return with renewed force. Finally, Valvo's physician put him on an antidepressant--which not only relieved the depression but also made him a convert to a new way of thinking about illness and health. "Did my heart operation cause the depression I'm experiencing?" he wrote recently in an article for a newsletter for a chapter of Mended Hearts, a support group for heart patients and their families. "Does depression cause heart disease? The answer to both those questions is probably yes."
A few years ago, doctors would have dismissed Valvo as a New Age crank. But these days he is solidly in the medical mainstream.
More and more doctors--and patients--recognize that mental states and physical well-being are intimately connected. An unhealthy body can lead to an unhealthy mind, and an illness of the mind can trigger or worsen diseases in the body. Fixing a problem in one place, moreover, can often help the other.
The brain, after all, is only another organ, and it operates on the same biochemical principles as the thyroid or the spleen. What we experience as feelings, good or bad, are at the cellular level no more than a complex interaction of chemicals and electrical activity. Depression represents an imbalance in that interaction, one that can kill just as directly as more obviously physical ailments. Each year in the U.S., an estimated 30,000 people commit suicide, with the vast majority of cases attributable to depression. But depression's physical toll goes far beyond the number of people who take their own life and even beyond the impact on depressed people's relationships and productivity (which costs the U.S. economy some $50 billion a year).
The pathology of depression shows with especial clarity that mind and body aren't separate at all; they are part of a single system. In the case of depression, this interconnectedness takes the insidious form of making other serious diseases dramatically worse. Once you have had a heart attack, for example, your risk of dying from cardiovascular disease is four to six times greater if you also suffer from depression.
It's not just that people tend to be depressed because they have a life-threatening illness or that depressed people smoke, are too lethargic to take their medicine or aren't motivated to eat right or exercise. "Even when we take those factors into consideration," says Dr. Dwight Evans, a professor of psychiatry, medicine and neuroscience at the University of Pennsylvania, "depression jumps out as an independent risk factor for heart disease. It may be as bad as cholesterol."