Insulin resistance due to obesity should also be considered: obesity increases levels of intramyocellular TG in skeletal muscle, which impairs insulin sensitivity.30 In the present study, obesity-related parameters such as weight, BMI, and waist circumference were higher in patients with mental disorders than in those without, and these conditions might have increased the serum levels of TG and insulin. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.