Carney says that "the findings didn't surprise us".
"Many studies have reported that depression predicts increased mortality, but it's rare to delve into this kind of research as deeply and as carefully as we have. Although we suspected we would find this link, having gone through all of these studies and conducted such a careful evaluation, we are more confident than ever that depression is a risk factor for mortality in people who have heart disease."
Carney and Freedland were chosen to be part of the expert panel because they have been studying depression's effects on heart disease for more than 25 years, first reporting in 1988 that depression predicts an increased risk of cardiac problems in patients with existing heart disease. Hundreds of studies have been conducted since then, and most have supported their initial observation.
Carney noted that when people lose weight, lower their blood pressure or quit smoking, their risk of heart disease is lowered. But so far, no studies have shown that treating depression lowers cardiac risk.
"Unfortunately, very few studies have looked at that question," Carney explained. "And only one study has included enough subjects to determine whether treating depression could lower the risk of having a heart attack or dying from heart disease. Treatment did not lower the risk of heart attack or death, but that was the first study of its kind. More clinical trials are needed to identify treatments that may improve heart health along with depression."