Chinese herbal medicine for schizophrenia

Traditional Chinese medicine (TCM) was the main form of treatment in China for psychiatric illnesses until the development of antipsychotic drugs in the 1950's. Antipsychotic drugs have become the primary intervention for schizophrenia, although herbal medicines can still form part of the treatment.

To review Chinese herbal medicine, used alone or as part of a TCM approach, for people with schizophrenia and related psychoses.

We undertook electronic searches of the Cochrane Schizophrenia Group's register (December 2003), the Traditional Chinese Medical Literature Analysis and Retrieval Database (TCMLARS) (October 2003), Chinese Biomedical Database (CBM) (December 2003), China National Knowledge Infrastructure Database (May 2004), Complementary Medicine Database (AMED) (December 2003). We contacted the Chinese Cochrane Centre, the Cochrane Complementary Medicine Field and first authors of included studies and inspected reference lists for additional studies.

We included all relevant randomised controlled trials involving people with schizophrenia-like illnesses, allocated to Chinese herbal medicine, including any Chinese herbs (single or mixture), compared with placebo/no treatment or antipsychotic drugs.

We independently extracted data and calculated fixed effects relative risk (RR), the 95% confidence intervals (CI) for homogeneous dichotomous data, and, where appropriate, the number needed to treat (NNT) on an intention-to-treat basis. For continuous data, we calculated weighted mean differences (WMD).

Only one small trial of the seven included studies truly evaluated TCM for schizophrenia. The other trials evaluated Chinese herbs for schizophrenia. We found one study comparing Chinese herbal medicine with antipsychotic drugs. Data for the global state outcome 'no change/worse' favoured people allocated to antipsychotic medication (n=90, RR 1.88 CI 1.2 to 2.9, NNH 4 CI 2 to 12). Six trials compared Chinese herbal medicine in combination with antipsychotic with antipsychotic drugs alone. One trial found global state 'not improved/worse' favoured the herbal medicine/antipsychotic combination (n=123, RR 0.19 CI 0.1 to 0.6, NNT 6 CI 5 to 11). Two studies (n=103) also found short-term data from the Clinical Global Impression scale favoured the herbal medicine plus antipsychotic group (WMD -0.46 CI -0.9 to -0.1) compared with those given only antipsychotics. Significantly fewer people in the experimental group left the study early compared with those given antipsychotics alone (n=1004, 6 RCTs, RR 0.30 CI 0.16 to 0.58, NNT 21 CI 18 to 35). Reports of constipation were significantly lower in the treatment group compared to those receiving antipsychotics (n=67, 1 RCT, RR 0.03 CI 0.0 to 0.5, NNH 2 CI 2 to 4).

Chinese herbal medicines, given in a Western biomedical context, may be beneficial for people with schizophrenia when combined with antipsychotics. Traditional Chinese medicine is also under-evaluated, but results from one pioneering study that attempted to evaluate TCM should encourage further trials.