Extract of Ginkgo biloba Treatment for Tardive Dyskinesia in Schizophrenia: A Randomized, Double-Blind, Placebo-Controlled Trial

Objective: Free radicals may be involved in the pathogenesis of tardive dyskinesia (TD). Extract of Ginkgo biloba (EGb) is a potent antioxidant possessing free radical-scavenging activities. The aim of the study was to evaluate the efficacy of EGb-761, a standardized extract given in capsule form, in treating TD in schizophrenia patients.

Method: Inpatients with DSM-IV-diagnosed schizophrenia and TD (n = 157) in a mainland China Veterans Affairs psychiatric hospital were randomly assigned to 12 weeks of treatment with either EGb-761, 240 mg/d (n = 78) or a placebo (n = 79) in a double-blind manner. Primary outcome measures were (1) change from baseline in the Abnormal Involuntary Movement Scale (AIMS) score and (2) proportion of patients with a ≥ 30% reduction in their AIMS total score at week 12. Secondary outcome measures included the Positive and Negative Syndrome Scale (PANSS) and cognitive performance as measured by the Continuous Performance Test-37 Version and the 3-card Stroop task. Patients were recruited for the study between December 2006 and May 2007.

Results: Of the 157 patients who were randomly assigned, 152 (96.8%) completed the study. EGb-761 treatment significantly decreased the AIMS total score in patients with TD compared to those who were given a placebo (2.13 ± 1.75 vs −0.10 ± 1.69; P < .0001), with 40 (51.3%) and 4 (5.1%) patients achieving response in the EGb-761 and placebo treatment groups, respectively. There were no between-group differences in the PANSS total score or cognitive measures from baseline to week 12.

Conclusions: EGb-761 appears to be an effective treatment for reducing the symptoms of TD in schizophrenia patients, and improvement may be mediated through the well-known antioxidant activity of this extract.

Trial Registration: clinicaltrials.gov identifier: NCT00672373

J Clin Psychiatry

Submitted: February 10, 2009; accepted October 29, 2009.

Online ahead of print: September 21, 2010 (doi:10.4088/JCP.09m05125yel).

Corresponding author: Dong-Feng Zhou, MD, Institute of Mental Health, Peking University, No. 51 Hua Yuan Bei Rd, Hai Dian District, Beijing 100191, China (zhoudf@bjmu.edu.cn); or Xiang-Yang Zhang, PhD, Center for Biological Psychiatry, Beijing Hui-Long-Guan Hospital; De Sheng Men Wai Rd, Chang Ping District, Beijing 100096, China (zhangxy9@gmail.com).