Efficacy of Wendan Decoction combined with conventional medicine for depression: a systematic review and...

Wendan Decoction is well-known traditional Chinese medicine formula commonly used in China for the treatment of gastrointestinal disorders and mood disorders related to phlegm-dampness and spleen deficiency. In clinical practice, depending on different symptoms, additional herbs may be included, resulting in a modified formula known as modified Wendan Decoction.

To evaluate the efficacy of modified Wendan Decoction plus conventional medicine in the treatment of depression.

We independently conducted a meta-analysis of studies on the efficacy of modified Wendan Decoction for depression from inception to February 28, 2025, using electronic databases, including PubMed, Embase, Cochrane, Web of Science, Wanfang, VIP and SinoMed. Data from randomized controlled trials were extracted to evaluate treatment outcomes based on depression scales.

A total of 402 articles were identified through database searches, and 13 studies, encompassing 1117 patients, were included. The initial pooled analysis revealed a significant treatment effect of the experimental group, yielding a standardized mean difference (SMD) of -4.84 (95% CI: -7.54 to -2.14), with high heterogeneity (I² = 99%). Sensitivity analysis, excluding studies with high risk of bias, demonstrated an SMD of -4.18 (95% CI: -5.26 to -3.10) with moderate heterogeneity (I² = 83%). Notable regional differences were found, with the study in Southern region exhibiting greater efficacy (SMD = -4.81, 95% CI: -6.38 to -3.23) compared to the study in Northern region (SMD = -3.03, 95% CI: -3.73 to -2.32).

Our meta-analysis supports the efficacy of combining modified Wendan Decoction with conventional medicine for treating depression. Exploratory subgroup results suggest slightly greater improvements in Southern China, though this finding requires cautious interpretation and confirmation in future high-quality trials. PROSPERO Registration ID: CRD420251015690.