Several studies have shown oxidative stress in schizophrenia, including disrupted activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH)15–18; increased lipid peroxidation products, thiobarbituric acid reactive substances (TBARS), and malondialdehyde (MDA)19–22; as well as decreased nonenzymatic antioxidants in plasma, serum, red blood cells, and cerebrospinal fluid23,24. This evidence concerns the gene CAT and schizophrenia.