Extract of Ginkgo biloba for Tardive Dyskinesia: Meta-analysis of Randomized Controlled Trials

Free radicals may be involved in the pathogenesis of tardive dyskinesia (TD). We conducted this meta-analysis to systematically examine the efficacy of extract of Ginkgo biloba (EGb), a potent antioxidant possessing free radical-scavenging properties, as a treatment for TD in schizophrenia using randomized controlled trial (RCT) data.

Drawn from English and Chinese databases, 3 RCTs of EGb augmentation of antipsychotics (APs) vs. AP plus placebo or AP monotherapy were identified. 2 evaluators extracted data. The primary outcome measure was the severity of TD symptoms assessed by the Abnormal Involuntary Movement Scale (AIMS). Weighted mean difference (WMD) and risk ratio (RR) ±95% confidence intervals (CI) were calculated. Statistical analyses were performed using Review Manager (version 5.1.7.0) and STATA (version 12.0).

The 3 RCTs (n=299) from China, of 12 weeks duration, involved schizophrenia patients with TD of 55.9±13.4 years old. EGb (240 mg/day) outperformed the control group in reducing the severity of TD and clinical symptoms as measured by the AIMS (trials=3, n=299, WMD: -2.30 (95%CI: - 3.04, -1.55), P<0.00001) and the adverse drug reactions as assessed by the Treatment Emergent Symptom Scale (TESS) (trials=2, n=142, WMD: -2.38 (95%CI: -4.01, -0.74), P=0.004). Both the Positive and Negative Syndrome Scale (PANSS) total score (trials=2, n=239, P=0.87) and all-cause discontinuation (trials=3, n=299, P=0.21) were similar between the EGb and control group.

This meta-analysis suggests that adjunctive EGb appeared to be an effective and safe option for improving TD in the treatment of schizophrenia patients. However, better RCTs are needed to demonstrate its efficacy and safety especially on cognitive function in TD.

CRD42015024930.