Depression has been linked to type 2 diabetes, according to a new study.

Researchers from McGill University found that depression can significantly increase the risk of the metabolic disease in people suffering from obesity, high blood pressure and unhealthy cholesterol levels.

While the latest findings aren't the first to link mental health issues to type 2 diabetes, researchers noted that study analysis reveals that the combination of depression and metabolic risk factors can multiply the risk of type 2 diabetes.

"Emerging evidence suggests that not depression, per se, but depression in combination with behavioral and metabolic risk factors increases the risk of developing type 2 diabetes and cardiovascular conditions," said study lead Norbert Schmitz, an associate professor in McGill's Department of Psychiatry and a researcher at the affiliated Douglas Mental Health University Institute. "The aim of our study was to evaluate characteristics of individuals with both depressive symptoms and metabolic risk factors."

The latest study was four-and-a-half-years long and involved 2,525 participants in Quebec between the ages of 40 and 69.

Researchers in the latest study divided participants into four different groups. One group had depression symptoms as well as three or more metabolic risk factors; the second group only had depression; the third group only had metabolic risk factors and the fourth control group had neither depression or metabolic symptoms.

Study analysis did not link depression by itself to a significantly higher risk of developing type 2 diabetes. However, participants in the group suffering from depression and metabolic risk factors were six times more likely to develop type 2 diabetes. Researchers note that those in the metabolic risk factor but no depression group were four times more likely to develop type 2 diabetes.

Researchers wrote that the findings "suggested that the combined effect of depressive symptoms and metabolic dysregulation was greater than the sum of individual effects. An interaction between depression and metabolic dysregulation was also suggested by a structural equation model. Our study highlights the interaction between depressive symptoms and metabolic dysregulation as a risk factor for type 2 diabetes. Early identification, monitoring and a comprehensive management approach of both conditions might be an important diabetes prevention strategy."

"Focusing on depression alone might not change lifestyle/metabolic factors, so people are still at an increased risk of developing poor health outcomes, which in turn increases the risk of developing recurrent depression," Schmitz added.

The findings are published in the journal Molecular Psychiatry.