A Norwegian study shows the importance of treating depression early because it can have deadly consequences for the heart.

Depression can make life difficult, but new research has shown that serious depression symptoms can also cut many lives short. 

A study of nearly 63,000 Norwegians found that people with depression also have a 40 percent greater chance of suffering from heart failure than their peers.

The study, presented Friday at the EuroHeartCare 2014 conference in Stavanger, Norway, examined the long-term effects of depression and emphasized the importance of getting help early.

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The link between depression and heart problems is well known, but this new study shows how the severity of depressive symptoms can make a person’s heart health worse.

“We found a dose response relationship between depressive symptoms and the risk of developing heart failure.” study author Lise Tuset Gustad, an intensive care nurse at Levanger Hospital in Norway, said in a statement. “That means that the more depressed you feel, the more you are at risk.”

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Researchers began collecting data from a group Norwegian citizens in 1995, including their body mass index, physical activity levels, blood pressure readings, and tobacco smoking habits. They assessed their depression levels using a standardized clinical scale.

During the 11-year study, nearly 1,500 people developed heart failure. When compared to people without depression, people with mild depressive symptoms were found to have a five percent increased risk of heart failure. Those with moderate to severe symptoms had a 40 percent greater 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,” Gustad said. “This means we can be confident that these factors did not cause the association.”

People with depression sometimes self-medicate with unhealthy food, alcohol, smoking, or drugs. Mixed with a lack of motivation that can keep them from being active, these habits can create a mixture that is toxic to the heart.

“Depression is disabling. It blocks people’s ability to take their medications as prescribed, stop smoking, improve their diet or exercise more,” Gustad said.

Depression can also manifest in physical ways that negatively affect the heart. It triggers the release of stress hormones, which accelerate a person’s breathing and heartbeat.

“Those stress hormones also induce inflammation and atherosclerosis, which may accelerate heart diseases,” Gustad said. “Another mechanism could also be because depressed people find it more difficult to follow advice about how to take medications and improve their lifestyle.”

Because depression and other mental illnesses rarely travel alone, Gustad recommends that patients in hospitals should be screened for depression so that treatments can target existing illness as well as improve their overall health.