A new study out of King’s College in London investigates the connection between mental illness and Type II diabetes.

What comes first—mental illness or impaired blood sugar metabolism?

Researchers from Kings College tried to untangle the causes in the new study. Is the increased risk due to underlying causes of the mental illness? Is it caused by the mental illness itself? Or is Type II diabetes a side effect of treatments for mental illness?

Researchers reviewed 16 case control studies to determine whether blood sugar metabolism was impaired in patients with their first episode of major mental illness. Patients with mental illness in the study were otherwise physically healthy. They had no illnesses that would be expected to adversely affect blood sugar metabolism. In addition, they had not received any psychiatric medications previously.

Overall, the researchers found that patients with mental illness had significantly higher blood sugar and insulin levels. They also showed signs of insulin resistance. They did not, however, show any significant differences in hemoglobin A1C levels, the traditional measure of long-term blood sugar levels over a period of four to six months. Of course, antipsychotic drugs themselves can cause Type II diabetes. But these patients were chosen because they hadn’t taken any antipsychotic drugs previously. Poor diet and exercise are also risk factors for developing Type II diabetes. But the researchers controlled for these factors in their analysis as well.

This new research demonstrates that alterations in blood sugar metabolism are present from the very first onset of mental illness. The high rate of Type II diabetes in patients with new-onset major mental illness may also help explain the much higher mortality rates seen in these patients.

Holistic approach needed for patients with mental illness

The researchers concluded that physicians need to take a more holistic approach to treatment of major mental illness. This approach is even more critical because some psychiatric drugs worsen the risk of developing Type II diabetes in the first place.