A major new report has led to a big discovery regarding mental illnesses such as depression that suggests that it is tied to another condition that most people don’t realize: heart disease. While many people think of the treatments of these two conditions as vastly different, with one involving surgery and the other involving therapy, scientists have found that there are some surprising ties between the two.

Recent studies have found that between 17 and 44 percent of patients with coronary artery disease also have major depression, and those who are hospitalized for a heart attack are three times as likely to experience depression as those who have not.

While it makes sense that having heart disease could lead to depression, scientists have found it also works in the reverse, with depression leading to heart disease. And they’re not sure why that is, although it may have something to do with changing one’s lifestyle due to mood.

Either way, it’s a concerning finding that will require more research, and it shows that depression should not be dismissed as simply feeling moody, but treated as a serious medical condition that requires extensive treatment.

“Meanwhile there is little doubt that depression is a risk factor for cardiovascular diseases,” explains Karl-Heinz Ladwig.  “The work is based on a prospective population-based data set from the MONICA/KORA* study that, with a total term of up to 25 years, is one of the few large studies in Europe that allows such an analysis,” reports the statistician Dr. Jens Baumert of Helmholtz Zentrum München, who was also involved in the publication.