Insulin resistance is associated with current major depressive disorder (MDD) but not with remitted MDD, according to a study reported in a research letter in JAMA Psychiatry online.
The findings suggest “that insulin resistance is a state, rather than trait, biomarker of depression,” wrote lead author Kathleen T. Watson, PhD, of the Stanford School of Medicine in California, and colleagues.
To better characterize known associations between insulin resistance and major depressive disorder, researchers investigated two biomarkers of insulin resistance—the quantitative insulin sensitivity check index (QUICKI) and the triglyceride-to-high-density lipoprotein (HDL) ratio—in participants from the Netherlands Study of Depression and Anxiety. Researchers divided 1269 participants with proteomic data into 3 groups: those with current MDD, remitted MDD, and no history of MDD.
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Compared with no history of MDD, current MDD was associated with insulin resistance, although researchers found no such association when the disorder was remitted.
Results indicating insulin resistance from both the QUICKI and triglyceride-HDL ratio measures were positively associated with depression severity in participants with current MDD, according to the study. However, depression chronicity was associated only with insulin resistance signaled by the triglyceride-HDL ratio, and not the QUICKI.
“Taken together, these biomarkers of metabolic dysfunction represent simple, clinically accessible methods of identification of insulin resistance among currently depressed patients,” researchers wrote.
“Longitudinal analyses need to extend these findings and examine temporality,” they added, “and are the subject of our current investigations.”
Watson KT, Simard JF, Henderson VW, et al. Association of insulin resistance with depression severity and remission status: defining a metabolic endophenotype of depression. JAMA Psychiatry. 2020 December 2;[Epub ahead of print].