OBJECTIVETo investigate the relationship between efficacy of Chaihu Taoren Decoction (CTD) and the polymorphism of valine-alanine missense mutation of 9th codan (Val9Ala, T1183C) of superoxide dismutase (SOD) in patients with tardive dyskinesia (TD).

METHODSSeverity of TD was assessed by abnormal involuntary movement scale (AIMS), and the psychologic symptoms were rated by the positive and negative symptoms scale (PANSS). The sample size consisted of 119 patients with TD assigned to the TD group, 129 patients of chronic schizophrenia with the general condition matched strictly with that of the enrolled TD patients assigned to the non-TD group, and 148 healthy persons assigned to the normal group. The gene distribution rate of Val9Ala gene was analyzed using polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) analysis, and the therapeutic effect of CTD on 36 patients with TD was observed after 12 weeks treatment.

RESULTSThere was no significant difference in genotype and allelic gene frequency of SOD Val9Ala among the TD, non-TD and normal groups (P > 0.05). Comparison of the AIMS score in TD patients with various Val9Ala genotypes showed that the difference of AIMS scores in patients with TT and CT genotype was not significant (P > 0.05), but CTD did show a better efficacy in TD patients with CT heterozygote than in those with TT homozygote (P < 0.05).

CONCLUSIONThe CTD could effectively relieve the symptoms of TD, its efficacy might be related with the genotype of SOD, and 9Ala is considered to be a protective factor for the susceptibility to TD.