Wendan decoction (温胆汤) for treatment of schizophrenia: a systematic review of randomized controlled trials

To assess the beneficial and adverse effects of Wendan Decoction (温胆汤, WDD) for the treatment of schizophrenia.

Five electronic databases were searched until May 2014, including the Chinese National Knowledge Infrastructure, the Chinese Biomedical Literature Database, the Chinese Scientist Journal Database, PubMed, and the Cochrane Central Register of Controlled Trials in the Cochrane Library. The randomized controlled trials (RCTs) testing WDD against placebo, antipsychotic drugs, or WDD combined with antipsychotic drugs against antipsychotic drugs alone were included. Study selection, data extraction, quality assessment, and data analyses were conducted according to the Cochrane standards.

Thirteen RCTs (involving 1,174 patients) were included and the methodological quality was evaluated as generally low. The pooled results showed that WDD combined with antipsychotic drugs were more effective in clinical comprehensive effect, Positive and Negative Syndrome Scale (PANSS) scores and Brief Psychiatric Rating Scale scores compared with antipsychotic drugs alone. However, WDD had less effectiveness compared with antipsychotics in clinical comprehensive effect; and WDD was not different from antipsychotic drugs for PANSS scores. The side effects were significantly reduced in the intervention group compared with the control group.

WDD appears to be effective on improving symptoms in patients with schizophrenia. However, due to poor methodological quality in the majority of the included trials, the potential benefit from WDD needs to be confirmed in rigorous trials and the design and reporting of trials should follow the international standards.