According to a systematic review, for FTO and leptin and leptin receptor genes (LEP and LEPR), for the methylenetetrahydrofolate reductase (MTHFR) gene, and for the serotonin receptor 2C gene (HTR2C), there is strong evidence of association with MetS in schizophrenia patients [23]. This evidence concerns the gene MTHFR and schizophrenia.