An aberration in the level of antioxidants has been suggested in schizophrenia. Therefore, this study examined the difference in the antioxidant level between patients with schizophrenia and healthy controls, as well as the difference between the drug-naïve schizophrenic patients with a first episode (FSPR) and the risperidone-treated chronic schizophrenia (RCSPR) patients. The plasma albumin, bilirubin and uric acid levels were determined in 47 FSPR and 55 chronic schizophrenia patients who met the DSM-IV criteria for schizophrenia, and in 68 controls. The albumin and bilirubin levels were significantly lower in the schizophrenic patients compared to the controls, although there was no significant difference between the FSPR and RCSPR patients. The bilirubin level was significantly lower in the negative subgroup of the patient group. This study supports the hypothesis that an aberration in the antioxidant levels may be involved in schizophrenia. In addition, this study suggests that the antioxidant level may be associated with the clinical symptomatology as well as the treatment implications in schizophrenia, particularly the negative symptoms.