Wendan Decoction for Schizophrenia

Background

Wendan decoction (WDD) is one of the classical Chinese herb formulas used for psychotic symptoms. It is thought to be safe, accessible, and inexpensive.

Objectives

To investigate the effects of WDD for treatment of people with schizophrenia or schizophrenia-like illness compared with placebo, antipsychotic drugs, and other interventions for outcomes of clinical importance.

Search Methods

We searched the Cochrane Schizophrenia Group’s Trials Register (February 2016), which is based on regular searches of CINAHL, BIOSIS, AMED, EMBASE, PubMed, MEDLINE, PsycINFO, China biomedical databases group (SinoMed, CNKI, VIP, Wanfang), and clinical trials registries. There is no language, date, document type, or publication status limitations for inclusion of records in the register. We also inspected references of identified studies and contacted relevant authors for additional information.

Selection Criteria

All randomized clinical trials focusing on WDD for schizophrenia.

Data Collection and Analysis

We extracted data independently. For binary outcomes, we calculated risk ratio (RR) and its 95% confidence interval (CI), on an intention-to-treat basis. For continuous data, we estimated the mean difference (MD) between groups and its 95% CI. We employed a fixed-effect model for analyses.

Main Results

This review included 15 studies testing WDD across four different comparisons. When WDD was compared with no treatment, the outcome of “Global state—no clinically important improvement (PANSS < 50% reduction)” showed a clear difference (n = 72, 1 RCT, RR 0.53 CI 0.39 to 0.73, moderate quality). When WDD was compared with antipsychotic, the outcome of “Global state—no clinically important improvement (PANSS < 50% reduction)” showed no clear difference (n = 230, 3 RCTs, RR 1.15 CI 0.96 to 1.38, moderate quality); the mean mental state—average PANSS total score in the intervention groups was 0.84 higher (4.17 lower to 5.84 higher, n = 140, 2 RCTs, moderate quality); the outcome of adverse effects—EPS (TESS) was a clear difference (n = 140, 2 RCTs, RR 0.02 CI 0 to 0.15, moderate quality). When WDD plus normal dose antipsychotic was compared with normal dose antipsychotic, the outcome of “Global state—no clinically important improvement (PANSS < 50% reduction) showed a clear difference (n = 684, 6 RCTs, RR 0.6 CI 0.5 to 0.72, moderate quality); the mean mental state—average PANSS total score in the intervention groups was 11.64 lower (13.33 to 9.94 lower, n = 580, 5 RCTs, moderate quality); the outcome of adverse effects—EPS (TESS) was a clear difference (n = 308, 2 RCTs, RR 0.46 CI 0.3 to 0.7, moderate quality); the outcome of adverse effects—weight change was no clear difference (n = 108, 1 RCT, RR 0.5 CI 0.2 to 1.24, moderate quality); the mean use of antipsychotic—drug dose at the end point in the intervention groups was 0.7 lower (0.87 to 0.53 lower, n = 107, 1 RCT, moderate quality). When WDD plus low dose antipsychotic was compared with normal dose antipsychotic, the outcome of “Global state no clinically important improvement (PANSS < 50% reduction) was a clear difference (n = 522, 7 RCTs, RR 0.69 CI 0.51 to 0.93, moderate quality); the mean mental state—average PANSS total score in the intervention groups was 9.53 lower (17.82 to 1.24 lower, n = 250, 4 RCTs, moderate quality); the outcome of adverse effects—EPS (TESS) was a clear difference (n = 280, 3 RCTs, RR 0.29 CI 0.16 to 0.51, moderate quality). Notable across all comparisons was that we found no data on outcomes about quality of life, hospital service, and economics.

Authors’ Conclusions

Limited evidence suggested that WDD may have some antipsychotic effects as measured on global and mental state. Most important, WDD showed good features and potentials in reducing the side effects induced by antipsychotic drugs. Better designed large studies are needed to fully and fairly test the effects of WDD for people with schizophrenia (for full details please see figure 1 Deng and Xu¹).

Fig. 1.

Comparison: WENDAN decoction plus normal dose antipsychotic versus normal dose antipsychotic. Outcome: Global state: No clinically important improvement (PANSS < 50% reduction).