Previous researchers indicate that impaired cognitive flexibility was the primary factor distinguishing patients with from those without tardive dyskinesia (TD)1, and cognitive dysfunction correlates positively with the severity of TD2. Longitudinal data raised the possibility that the association between cognitive dysfunction and TD may reflect not organic vulnerability to but rather a state marker for this movement disorder as "tardive dementia"3. Atypical antipsychotic had been reported to alleviate the severity of TD4 and improved neurocognitive function separately5. But no researchers ever investigated the correlation of the two effects simultaneously. This randomized, single-blind and controlled study compared the effect of atypical antipsychotic on TD, neurocognitive function and associated factors for these changes.

Eighty chronic schizophrenia inpatients who received conventional antipsychotics for more than one year, and met Schooler and Kane's criteria for persistent TD were enrolled in the study. The subjects were randomized to three groups: the olanzapine, amisulpride and FGA (first generation antipsychotic) controlled groups. Neurocognitive function were assessed using Wisconsin Card Sorting Test (WSCT) and Continuous Performance test (CPT) at baseline, 12th week and 24th week. Clinical successive ratings were performed with Brief psychiatric Rating Scale (BPRS), AIMS (Abnormal Involuntary Movement Rating Scale), Simpson-Angus Rating Scale (SAS), Udvalg for Kliniske Undersogelser side effect ratings (UKU) and Barnes akathesia scale (BAS).To evaluate the influences of prognostic factors on tardive dyskinesia and neurocognitive function and to control for all potential confounding variables, longitudinal analyses on the repeated measures data were conducted using generalized estimating equation models (GEE).

Inclusion Criteria:

• schizophrenia inpatients who received conventional antipsychotics for more than one year,
• those who met Schooler and Kane's criteria for persistent TD.

Exclusion Criteria:

• mental retardation,
• organic mental disorder,
• pregnancy and allergy to trial drugs.