Type 2 patients who use only a sulfonylurea are less likely to take anti-depressant drugs than diabetes patients on other medications. That’s the conclusion of a report delivered recently in Honolulu at the annual meeting of the American Psychiatric Association.
The report, which summarized a retrospective study by a Norwegian researcher, said that diabetes patients taking a sulfonylurea as their only disease medication had the lowest likelihood of also being prescribed an antidepressant. The researcher, Øivind Hundal, MPharm, PhD, of Haukeland University Hospital in Bergen, theorized that the insulin-inducing properties of sulfonylureas may have an antidepressant effect on the brain, thus doing away with the need for other antidepressants.
Hundal had previously theorized that depression might be a form of “diabetes of the brain,” in which high cerebral glucose levels affect brain function and moods.
Hundal’s research team analyzed data from 3.4 million adult patients to see how the number of antidepressant prescriptions matched with the types of diabetes medications they were taking. Those medications included sulfonylureas, biguanides, and thiazolidinediones. After studying the data, Hundal concluded that sulfonylureas appeared to have a direct and beneficial effect on depression.
First developed in the 1950s, sulfonylureas are a class of drugs that work by stimulating insulin production in pancreatic beta cells. For years, the drugs were the first ones doctors and endocrinologists would prescribe to newly diagnosed type 2 patients. These days, a later drug, metformin, is often the drug first prescribed, partly because of its greater effect on overweight people.
Hundal’s findings suggest only a connection between insulin levels and depression, not causation. The hope is that further study could reveal ways to create more effective antidepressant drugs.