Korean researchers have identified a strong link between insulin resistance and the risk of depression.

A team at Kangbuk Samsung Hospital analyzed data from about 233,000 adults who underwent at least two checkups at the hospital’s screening center between 2011 and 2022. The study was led by Professor Oh Dae-jong of the hospital’s Corporate Mental Health Research Institute, together with Professors Jeon Sang-won and Cho Sung-joon of the Department of Psychiatry.

Using the HOMA-IR (Homeostatic Model Assessment for Insulin Resistance), the researchers categorized participants into four groups. Depression was defined as a score of 16 or higher on the Center for Epidemiologic Studies-Depression (CES-D) scale.

Results showed that individuals in the highest HOMA-IR group had about a 15 percent greater risk of depression than those in the lowest group. The risk was especially elevated among young adults under 40, those with normal blood glucose levels, people who were overweight, and individuals with a high fat-to-muscle mass ratio.

“This study is significant as it identifies insulin resistance as a factor increasing depression risk through the world’s largest cohort study,” Professor Oh said. “It underscores the close connection between mental health and metabolic health.”

Professor Jeon added, “These findings suggest that measuring insulin resistance could help in the early detection of high-risk groups for depression.”

The study was published in The Lancet Regional Health – Western Pacific.