Is depression as dangerous as smoking?

A 12-person panel has published a paper in the journal Circulation saying that their review of literature indicates that depression should be listed with smoking, obesity, diabetes and high blood pressure as risk factors for heart disease.

The National Institute of Mental Health has already said it won't use DSM-5 as anything more than a glossary of terms and equating depression to smoking in heart disease is not going to get depression covered on insurance plans the way diabetes is, it is going to put psychology claims farther on the fringes of the evidence-based community. Finding two curves that go in the same direction and implying causation is not all that hard.

 And the data is still not there. 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. 

But maybe others did not look hard enough. The group did a review of studies to find a link between depression and heart problems. Most of the studies found that people who had a heart attack or die from heart disease were also more likely to list depression.

"The findings didn't surprise us," said Robert M. Carney, PhD, a professor of psychiatry at Washington University School of Medicine in St. Louis, in their statement. "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."

Will treating depression help with heart disease the way quitting smoking does? 

"Unfortunately, very few studies have looked at that question," said Carney. "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."

Part of the problem is that psychology/psychiatry treatments don't work for everyone. Even the best therapies for depression lead to remission half the time. 

Carney and Kenneth E. Freedland, PhD, also a professor of psychiatry at Washington University, are set to begin a new clinical trial to evaluate whether a different approach to treatment can be more successful in alleviating depression and lowering the risk of future cardiac events.

What is known with certainty is that not treating depression can have negative effects on health and quality of life. So if it helps with heart disease, that would be a bonus.