•We retrieved electronic databases, especially the Chinese periodical databases. •Eight randomized, double-blind, placebo-controlled trials were enrolled and analyzed. •Extract of Gb (EGb) ameliorated total and negative symptoms of patients. •EGb therapy might be safe and related to its dosage but need more evidence. •The pooled results might be restricted to the Chinese race and need more studies.
Our study was to review and evaluate the efficacy and safety of extract of Gb (EGb) as an adjuvant therapy to antipsychotics in chronic schizophrenia treatment. We searched Pubmed/Medline, Embase, PsycINFO, the Cochrane library, and especially the Chinese periodical databases. Finally, eight randomized, double-blind, placebo-controlled trials (RCTs) of 1033 patients were enrolled, with 571 cases in EGb group and 462 in placebo. The result showed that EGb had a significant difference in ameliorating total and negative symptoms of chronic schizophrenia as an adjuvant therapy to antipsychotics. Thus, the EGb therapy plus antipsychotics might be more efficacious. Although the studies describing adverse reactions showed no distinguishable difference between EGb and placebo group in mean total scores of Treatment Emergent Symptom Scale (TESS) or a Rating Scale for Extrapyramidal Side Effects (RSESE), the results of subscores varied in different studies. In addition, the severity of side effects of EGb might be related to its daily dosage. Therefore, the safety of EGb therapy in chronic schizophrenia treatment might need more evidence. And all of these eight trials were carried out in China; thus, the results might be restricted to the race and we need more high-quality studies of multi-center and randomized double-blind clinical trials to compare, analyze, and confirm the findings further.