REDUCED LEVEL OF PLASMA ANTIOXIDANT URIC-ACID IN SCHIZOPHRENIA

There is evidence of dysregulation of the antioxidant defense system i n schizophrenia. The purpose of the present study was to examine wheth er uric acid, a potent antioxidant, is reduced in the plasma of patien ts with schizophrenia. To this end, a within-subject, repeated measure s, on-off-on haloperidol treatment design was utilized. Male schizophr enic patients with either a haloperidol treatment (n = 47) or a drug-f ree condition (n = 35) had significantly lower levels of plasma uric a cid than the age- and sex-matched normal control subjects (n = 34). Fo llowing haloperidol withdrawal, plasma uric acid levels were further r educed in schizophrenic patients (P = 0.018; paired t-test, n = 35). H owever, no relationship was found between uric acid levels and the len gth of the drug-free period (<5 or > 5 weeks) or days drug free. In ad dition, the plasma levels of uric acid in patient groups were signific antly and inversely correlated with psychosis. There was a trend for l ower uric acid levels in relapsed patients relative to clinically stab le patients. Smoking, which can modify plasma antioxidant capacity, wa s not found to have prominent effects on uric acid levels. The present finding of a significant decrease of a selective antioxidant provides additional support to the hypothesis that oxidative stress in schizop hrenia may be due to a defect in the antioxidant defense system. (C) 1 998 Elsevier Science Ireland Ltd. All rights reserved.