Depression can literally lead to a broken heart, new research suggests.

A study of about 63,000 people in Norway has shown moderate to severe depression increases the risk of heart failure by 40 percent.

The findings were presented at the annual meeting of the 80,000-member European Society of Cardiology, held April 4-5 in Stavanger, Norway.

The research was based on data collected by the Nord-Trøndelag Health Study, an epidemiological project that surveyed 63,000 of 97,000 residents of Nord-Trøndelag County, and represented one of the largest-ever investigations into whether depression increases the risk of developing heart failure.

"We found a dose response relationship between depressive symptoms and the risk of developing heart failure. That means that the more depressed you feel, the more you are at risk," Lise Tuset Gustad, first author of the study and an intensive care nurse at Levanger Hospital in Norway, said in a news release. "People who have lost interest in things they used to enjoy, such as reading or watching a television series, may have the early signs of depression. It's a good idea to see your doctor in these early stages for some advice on how to reduce your depression levels."

Starting in 1995, information was collected on the residents who agreed to participate in the study, including statistics such as body mass index, physical activity, smoking habits and blood pressure, whie depression was assessed and ranked for severity.

As every Norwegian citizen receives a unique 11 digit number at birth which is used at hospitals and the National Cause of Death Registry, the scientific team used that number to track which patients were hospitalized with or died from heart failure during the 11 year study.

Approximately 1,500 people ended up developing heart failure over the course of the research.

"Depression triggers stress hormones. If you're stressed you feel your pulse going up and your breath speeding up, which is the result of hormones being released. Those stress hormones also induce inflammation and atherosclerosis, which may accelerate heart diseases. Another mechanism could also be because depressed people find it more difficult to follow advice about how to take medications and improve their lifestyle," said Gustad.

Compared to residents who reported having no symptoms of depression, people with mild symptoms showed a 5 percent increased risk of developing heart failure, while those with moderate to severe symptoms saw a 40 percent increased risk.

"Depressive symptoms increase the chance of developing heart failure and the more severe the symptoms are, the greater the risk. Depressed people have less healthy lifestyles, so our analysis adjusted for factors such as obesity and smoking that could cause both depression and heart failure. This means we can be confident that these factors did not cause the association," she said.

"Depression is disabling. It blocks people's ability to take their medications as prescribed, stop smoking, improve their diet or exercise more," Gustad said. "Patients at all hospitals should be screened for depression to help them recover from existing illnesses, avoid developing new ones and have a more enjoyable life."