CBS Local — Antidepressants are known for having various side-effects and are warned to only be used while under a doctor’s care. A new study has found that the drugs may also be contributing to a higher risk of death for their users.

The findings, published by researchers at McMaster University in Canada, concluded that the risk of death was 33 percent higher among people taking antidepressants.

“We are very concerned by these results. They suggest that we shouldn’t be taking antidepressant drugs without understanding precisely how they interact with the body,” McMaster associate professor Paul Andrews said.

According to the researchers, the drugs can prevent major organs from absorbing serotonin – a vital chemical used by the heart, kidneys, lungs, and liver – from the body’s bloodstream. The results also found that antidepressant users had a 14-percent higher risk of having cardiovascular issues, like heart attacks and strokes.

Antidepressants treat, but do not cure depression, and are reportedly effective at improving mood, relieving anxiety, sleep problems, and suicidal thoughts.

Although they are generally regarded as safe, Andrews’ team is calling that assumption into question. “Our findings are important because they undermine this assumption,” researcher Marta Maslej said. “I think people would be much less willing to take these drugs if they were aware how little is known about their impact outside of the brain, and that what we do know points to an increased risk of death.”