Insulin has many physiological activities including reduction of blood glucose and stimulation of fatty acid synthesis, processes that become dysregulated in obesity due to hyperinsulinemia and the development of insulin resistance [50].We report here that the DIO-induced glucose dysmetabolism was surprisingly improved by chronic olanzapine treatment, with the VDC-O and VDS-O groups showing significantly improved glucose levels in an OGTT, while the VDC-O group also had an insulin resistance index. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.