Study: Insulin Resistance Linked to Major Depression

Insulin resistance has been linked to an increased risk of developing major depressive disorder, according to the results of a study at Stanford Medicine, published in the American Journal of Psychiatry.

“If you’re insulin-resistant, your risk of developing major depressive disorder is double that of someone who’s not insulin-resistant, even if you’ve never experienced depression before,” Natalie Rasgon, MD, PhD, professor of psychiatry and behavioral sciences, said in a press release.

Insulin-resistance is independent of the body’s ability to secrete insulin into the bloodstream as it is the decreased ability of cells throughout the body to use the hormone.

Approximately 40% of individuals who suffer from mood disorders are insulin resistant, according to Rasgon, so the link between mental disorders and insulin-resistance has already been established.

Investigators analyzed data from 601 individuals who had never been troubled by depression or anxiety. The 3 proxies measured were fasting blood glucose levels, waist circumference, and the ratio of circulating triglyceride levels to circulating high-density lipoprotein.

The results of the study showed that the 3 measurements were linked to an 89% increase in the rate of new major depressive disorder cases.

Every 5-centimeter increase of abdominal fat was related to an 11% greater rate of depression and an increase in fasting plasma glucose of 18 mg per deciliter of blood with a 37% increase of depression incidence.

In another phase, roughly 400 individuals who did not experience major depression or any signs of insulin resistance were analyzed. Around the 3-year mark of the study, nearly 100 of individuals became insulin-resistant.

Investigators compared those individuals to a group who had not become insulin-resistant.

Though the number of individuals was too small for the 3 measurement groups, it was concluded that these who were insulin-resistant were 2.66 times more likely to suffer from major depression at the 9-month follow up than those who were not insulin-resistant.

“It’s time for providers to consider the metabolic status of those suffering from mood disorders and vice versa, by assessing mood in patients with metabolic diseases such as obesity and hypertension,” Rasgon said in the press release. “To prevent depression, physicians should be checking their patients’ insulin sensitivity. These tests are readily available in labs around the world, and they’re not expensive. In the end, we can mitigate the development of lifelong debilitating diseases.”

An increasing proportion of the world’s population is insulin resistant, the statement said, for reasons that include excessive caloric intake, lack of exercise, stress, lack of sleep, and causes insulin receptors to fail to bind insulin.

Reference

Insulin resistance doubles risk of major depressive disorder, Stanford study finds. EurekAlert. News release. September 23, 2021. Accessed September 23, 2021. https://www.eurekalert.org/news-releases/928847