A meta-analysis of the efficacy and safety of traditional Chinese medicine formula Ganmai Dazao decoction for depression

Ethnopharmacological relevance: Ganmai Dazao (GMDZ) decoction is a traditional Chinese herbal formula commonly used for the treatment of depression. The objective of this study was to assess the efficacy and safety of GMDZ, either alone or as co-therapy, for depression.

Materials and methods: We systematically searched key databases (9 Chinese and 7 English) up until May 2013 for randomized controlled trials (RCTs). The primary outcomes were effective rate and self-rated or clinician-rated severity of depression. The secondary outcome was the occurrence of adverse events. Methodological quality of the RCTs was assessed by the Cochrane׳s risk of bias assessment.

Results: Ten RCTs were included. All were written in Chinese and the methodological quality was generally low. Pooled analysis of 5 studies which compared GMDZ with antidepressants showed that GMDZ was significantly more efficacious than antidepressants in effective rate (risk ratio: 1.14, 95% CI: 1.02 to 1.27, P=0.02, I(2)=0%), but comparable in Hamilton Depression Rating Scale (HDRS) score (mean difference: -2.10, 95% CI: -4.62 to -0.41, P=0.10, I(2)=92%). With regard to the other 5 studies which compared GMDZ plus antidepressants with antidepressants alone, there was no significant difference in effective rate (risk ratio: 1.24, 95% CI: 0.99 to 1.55, P=0.07, I(2)=93%), but the end-point HDRS score was significantly lower in GMDZ antidepressants combination (mean difference: -4.25, 95% CI: -6.50 to -2.00, P=0.0002, I(2)=96%). Adverse events were more common with antidepressants than GMDZ (rate ratio: 0.52, 95% CI: 0.32 to 0.82, P=0.005, I(2)=37%) and in antidepressants alone compared to GMDZ antidepressants combination (rate ratio: 0.23, 95% CI: 0.08 to 0.68, P=0.08, I(2)=0%).

Conclusion: The overall results suggest that GMDZ has few side effects and the potential as an antidepressant. Adding GMDZ to antidepressants reduces side effects and enhances efficacy of antidepressants. However, due to the small number of studies and their limitations, further studies with better methodological quality and more comprehensive safety assessment are needed to determine the benefits and risks of GMDZ in the treatment of depression.