We have determined the specific activities of some enzymatic antioxidant defenses like superoxide dismutase (SOD) and glutathione peroxidase (GPX), as well as a lipid peroxidation marker (MDA-malondialdehyde) from the serum of patients with schizophrenia, compared with a normal age-matched control group. The results showed an increased oxidative stress status in schizophrenic patients. These findings could raise some important issues concerning schizophrenia treatment, suggesting that one possible solution would be to associate antioxidants with the classical therapy.