1. Introduction
Review authors in the Cochrane Collaboration prepared a review of the effects of Wendan decoction in adults with schizophrenia. After searching for all relevant studies, they identified 15 studies comparing Wendan decoction to other interventions in people with schizophrenia. In 6 of these studies, people with schizophrenia continued taking their usual medicines for schizophrenia but were randomly selected to take Wendan decoction or not. This summary presents the findings of these studies.
1.1. Schizophrenia and Wendan decoction
Schizophrenia is a serious mental disorder characterized by hallucinations (false sensory experiences such as hearing voices), delusions (false beliefs that are improbable or bizarre), and other problems with thinking, emotion, and behavior. Schizophrenia leads to poor social and work-related functioning, and is often disabling. The symptoms of schizophrenia may be improved with antipsychotic medications. However, antipsychotics may have serious side effects such as extrapyramidal symptoms (movement problems) or weight gain and development of diabetes, and these side effects may lead people to stop taking antipsychotics. Wendan decoction is a combination of herbs that is used in Traditional Chinese medicine (TCM) to treat some mental, heart, and digestive symptoms. The typical Wendan decoction is made up of Rhizoma Pinelliae, Bambusae Caulis In Taeniam, Pericarpium Citri Reticulatae, Fructus Aurantii Immaturus, Poria Cocos, Rhizoma Zingiberis, Jujube and Radix Glycyrrhizae. Some TCM practitioners prescribe Wendan decoction instead of or together with standard antipsychotics. This review investigated whether using Wendan decoction together with a standard dose of antipsychotic medication could reduce the symptoms of schizophrenia, improve quality of life, and reduce serious side effects, in adults with schizophrenia or schizophrenia-like illness.
2. What does the research say?
There were 6 studies with 684 people who randomly received or did not receive Wendan decoction in addition to a standard dose of antipsychotic medication. The participants in the studies were all diagnosed with schizophrenia and the studies were all carried out in China. The antipsychotics used included risperidone, ziprasidone, aripiprazole, and olanzapine. In one study, the specific antipsychotics used were chosen depending on the type of symptoms. The Wendan formula was typical in 2 studies, and in 4 studies the herbal formula was modified to treat different symptoms. The doses of Wendan varied between studies, and in 2 studies the dose was not reported. The studies lasted from 6 weeks to 2 months.
Our overall certainty in the evidence for the effects was moderate to very low. None of the studies gave a clear description of how the participants were assigned to the treatment groups. The people providing the decoction, the researchers measuring the effects of the decoction, and the people in the studies knew whether they had the Wendan decoction or not. This knowledge could have had an effect on the outcomes of the people in the studies. For some outcomes, there was also very little data. Based on the evidence to date, for people with schizophrenia or schizophrenia-like symptoms, when Wendan decoction is added to usual antipsychotic treatment, it probably improves schizophrenia symptoms, and probably increases the chances of clinical improvement. It may also decrease the risk of developing movement problems, but it is uncertain whether it reduces the risk of gaining weight (see Table 1). No studies reported on quality of life outcomes. More studies of better quality and longer duration are necessary.
Table 1.
Summary of Findings Table. Effects of Wendan decoction for people with schizophrenia
| What was measured | Effect when not taking Wendan (antipsychotics alone) | Effect when taking Wendan plus antipsychotics | Quality of the evidencea | What happens when taking Wendan |
|---|---|---|---|---|
| Schizophrenia symptoms (5 studies, 580 people) Measured on the PANSS scale from 0 (better) to 210 (worse). | Average ranges from 38 to 58 | On average 11.64 units lower (from 9.94 to 13.33 lower) | ⊕⊕⊖⊖ moderate1 |
Wendan decoction probably decreases schizophrenia symptoms. |
| Number of people with clinically important improvement (6 studies, 684 people) Measured as ≥50% improvement on the PANSS. | 51 out of 100 people | On average 19 more people (from 11 to 27 more) | ⊕⊕⊕⊖ moderate1 |
Wendan decoction probably increases the number of people who experience clinical improvement. |
| Quality of life | -- | -- | -- | No studies reported on quality of life |
| Number of people reporting weight gain (1 study, 108 people) | 22 out of 100 people | On average 11 fewer people (from 18 fewer to 5 more) | ⊕⊖⊖⊖ very low2 |
Wendan decoction may decrease the number of people who gain weight, but it’s uncertain. |
| Number of people developing movement problems (2 studies, 308 people) | 35 out of 100 people | On average 19 fewer people (from 11 to 25 fewer) | ⊕⊕⊖⊖ low3 |
Wendan decoction may decrease the number of people who develop movement problems. |
Details about the quality of the evidence:
Evidence was moderate quality because the researchers and participants knew what intervention participants were receiving, and the people who measured outcomes may have known what intervention participants were receiving.
Evidence was very low quality because the researchers and participants knew what intervention participants were receiving, the people who measured outcomes may have known what intervention participants were receiving, and there were very few people in the study.
Evidence was low quality because the researchers and participants knew what intervention participants were receiving, the people who measured outcomes may have known what intervention participants were receiving, and there were few people in the study.
3. Where does this information come from?
This summary is based on a Cochrane systematic review: Deng H, Xu J. Wendan decoction (Traditional Chinese medicine) for schizophrenia. Cochrane Database of Systematic Reviews 2017, Issue 6. Art. No.: CD012217. DOI: 10.1002/14651858.CD012217.pub2.
Cochrane is an independent global network of people who publish Cochrane systematic reviews. Many of the people are volunteers who write reviews by finding and combining scientific studies to answer health care questions. These reviews may answer questions about whether, for example, certain vitamins work in diabetes. The Cochrane Complementary Medicine Field promotes Cochrane systematic reviews which cover complementary medicine in many conditions and diseases. For more information, please visit http://cam.cochrane.org.
Acknowledgments
This article was prepared on behalf of the Cochrane Complementary Medicine Field with funding from the US National Center for Complementary and Integrative Health (NCCIH) of the US National Institutes of Health (grant number R24 AT001293).
Footnotes
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