Study Finds Link Between Mental Health Disorders, Type 2 Diabetes

It is common for persons with mental illness to suffer comorbid conditions.

A new study has found a gene that may play a role in major mental disorders as well as regulating pancreatic beta cells that produce insulin, showing a biological link between what seem to be 2 very separate conditions.

The gene, DISC1, is believes to play a role in schizophrenia, bipolar disorder and some forms of depression, according to the study that appears in FASEB Journal, for the Federation of American Societies for Experimental Biology.

"Studies exploring the biology of disease have increasingly identified the involvement of unanticipated proteins—DISC1 fits this category," said Rita Bortell, PhD, a researcher involved in the work from the Diabetes Center of Excellence at the University of Massachusetts Medical School in Worcester, Massachusetts.

"Our hope is that the association we've found linking disrupted DISC1 to both diabetes and psychiatric disorders may uncover mechanisms to improve therapies, even preventative ones, to alleviate suffering caused by both illnesses which are extraordinarily costly, very common, often quite debilitating."

Researchers found the connection by comparing 2 groups of mice. The first was genetically altered to disrupt the DISC1 gene only in the pancreatic beta cells; the second group of mice was not altered.

The group with the altered gene experienced beta cell death, and thus less insulin secretion and impaired blood sugar control while the mice in the second group had no such effects. Through this process, the researchers found that the gene controlled a specific protein, GSK3β, which is critical for survival.

Blocking this protein caused improved beta cell function and brought glucose tolerance back to normal in the mice with the disrupted gene. The findings are significant, according the journal’s editor in chief, because they show that a therapy aimed at a single protein could affect multiple conditions. “These connections between these disorders may be surprising, but we have known for a long time that a single protein or gene can play multiple roles in the body,” wrote Thor Pederson, PhD.

It is common for persons with mental illness to suffer comorbid conditions such as diabetes; in fact, a major tenet of the Affordable Care Act is to promote care coordination for patients who have multiple chronic conditions. It’s not always been clear why this is the case. Some note that therapies for major mental health disorders can cause obesity or aggravate cardiometabolic conditions, while others point out that those who are depressed may be less likely to follow healthy diet and exercise regimens.

Pioneering work by researchers at the University of Washington showed that housing mental health professionals within a primary care practice increased the likelihood that patients with both diabetes and a mental health issue, such as depression, would seek improvement in both areas.