Depression and heart disease combined is a more lethal than either of these conditions on their own, a study of around 6,000 British civil servants.
Both conditions are already known to be responsible for increasing the risk of a person dying from heart attack or stroke but little research has been carried out on the effect of depression and heart disease combined.
A new study has shown the risk of death is higher for someone who has both conditions.
Scientists from the University of Versailles, France, and University College London followed around 6,000 middle-aged UK adults for their research. A fifth of the participants had both depression and heart disease.
A total of 170 people died while the research was being carried out, 47 of whom were killed by heart attack, stroke or other cardiovascular disease.
People with heart disease only were found to be two-thirds more likely to die from any cause than those who had neither depression nor heart disease.
Those with depression only were at least two times more likely to die than those who had neither condition, the researchers said.
But those who had both conditions were found to have a tripled risk of dying from any cause and a quadrupled risk of dying from cardiovascular disease.
The scientists said: “A major implication of these results is the need for healthcare professionals to pay more attention to depression in their cardiac patients.”