Insulin resistance measures may predict incident major depressive disorder

Surrogate insulin resistance measures positively predicted incident major depressive disorder among adults with no depression or anxiety disorder history, according to a study in American Journal of Psychiatry.

“Several studies showed an association between insulin resistance and depression,” Kathleen T. Watson, PhD, of the department of psychiatry and behavioral sciences at Stanford School of Medicine in California, told Healio Psychiatry. “Last year, in a study published in JAMA Psychiatry, we found that insulin resistance is related to being in a depressive episode and depression severity, but that study evaluated depression and insulin resistance at the same point in time.

“We did not know whether being insulin resistant first could lead to new cases of depression in the future, so this study attempts to address that question,” Watson added.

Watson and colleagues analyzed data of 601 individuals aged 18 to 65 years without a lifetime history of depression or anxiety disorder who participated in the multisite longitudinal Netherland Study of Depression and Anxiety, which evaluates the course and consequences of adult depressive and anxiety disorders. Incident major depressive disorder, defined via DSM-IV criteria, served as the study’s outcome. Triglyceride-HDL ratio, fasting plasma glucose level and waist circumference served as exposure measures.

Results showed major depressive disorder development among 14% of the sample during follow-up. Higher triglyceride-HDL ratio (HR = 1.89; 95% CI, 1.15-3.11), higher fasting plasma glucose levels (HR = 1.37; 95% CI, 1.05-1.77) and higher waist circumference (HR = 1.11; 95% CI, 1.01-1.21) had positive associations with increased risk for incident major depression, according to Cox proportional hazards models. The researchers noted a positive association between prediabetes development in the 2-year period after study enrollment and incident major depressive disorder (HR = 2.66; 95% CI, 1.13-6.27). However, they observed no association between the development of high triglyceride-HDL ratio and high central adiposity during the same period and incident major depression.

“We are also exploring the idea of the metabolic subtype of depression,” Watson said. “It is plausible that different treatments or approaches help manage depression in people with insulin resistance. These tools may inform clinical practices in the future.”

Reference:

Watson KT, et al. JAMA Psychiatry. 2020;doi:10.1001/jamapsychiatry.2020.3669.