Extract of Ginkgo Biloba and Tardive Dyskinesia

A Double-Blind, Randomised, Parallel-Group Comparison of Extract of Ginkgo Biloba(EGB-761) Versus Placebo as Add-on Medication in Patients With Established Tardive Dyskinesia

The purpose of this study is to determine whether Extract of Ginkgo Biloba is effective in the treatment on Tardive dyskinesia

Tardive dyskinesia(TD) is a common complication of conventional antipsychotic treatment in subjects with schizophrenia. There is no established treatment for TD patients.This disorder remains a significant clinical problem for both patients and physicians for the foreseeable future.

Inclusion Criteria:

• Male or female aged 18 to 60yrs
• Meeting Diagnostic and Statistical Manual of Mental Diseases, Fourth Edition(DSM-IV) criteria for schizophrenia or schizo-affective disorder
• Abnormal Involuntary Movement Scale (AIMS) score ≥2.
• Patients from whom informed, written consent is obtained.
• Patients who have been on a fixed dose of antipsychotic medication for at least 4 weeks prior to trial entry.

Exclusion Criteria:

• Significant neurological disorder other than TD
• Substance abuse
• Significant other medical illness
• Psychiatric disorder not stabilised
• Pregnancy or lactation
• Take antioxidants(such as Vitamin C)