Nearly 25 years of research has drawn a clear connecting line between depression and heart disease, making the link Exhibit A in the modern compendium of mind-body connections. But that research has yet to explain the connection. And it has yet to convince many cardiologists that depression care could be a tool in preventing and treating heart disease. "That you can die of a broken heart isn't a new idea. But unfortunately, the idea is much more complex than any of us expected," says Dr. Alexander Glassman, a psychiatrist with the New York Psychiatric Institute. Complex, yes. But the bond between heart disease and depression is also undeniable.