In this study, with a naturalistic experimental design, we genotyped a group of 517 physically stable patients with schizophrenia (248 women and 269 men) for 20 polymorphisms in the genes encoding insulin-induced gene 2 (INSIG2), ghrelin (GHRL), leptin (LEP), and the leptin receptor (LEPR), and examined whether differences existed between 378 patients without and 139 with MetS. This evidence concerns the gene INSIG2 and schizophrenia.