A systematic review on the efficacy, safety and types of Chinese herbal medicine for depression

•Over 90% of the included RCTs of CHM for depression had poor methodological quality.•Meta-analyses showed that CHM outperformed placebo in reducing depressive symptoms.•CHM monotherapy was as effective as antidepressants in reducing depressive symptoms.•The reviewed RCTs had many shortcomings and limited adequate safety data.•A clear conclusion on the efficacy and safety of CHM for depression was disallowed.

Chinese herbal medicine (CHM) is one of the commonly used complementary and alternative medicine therapies for major depressive disorder. The objective of this study was to review the efficacy, safety and types of CHM for depression. We systematically searched key databases (9 Chinese and 7 English) up until May 2013 for randomized controlled trials (RCTs) and examined 7 systematic reviews for additional articles. Methodological quality was assessed by modified Jadad scale and Cochrane's risk of bias assessment. Only studies with moderate methodological quality, defined as modified Jadad scale score ≥3, were included in meta-analysis for efficacy. Of the 296 RCTs that were assessed in details, 278 (93.9%) had modified Jadad scale score < 3, and only 21 scored ≥ 3. The frequently used formulas were Xiao Yao decoction, Chaihu Shugan decoction and Ganmai Dazao decoction; while Chaihu, Bai Shao and Fu Ling were the frequently used single herb. Meta-analyses showed that CHM monotherapy was better than placebo and as effective as antidepressants in reducing Hamilton Depression Rating Scale (HDRS) score (CHM vs. placebo: mean difference: −7.97, 95% CI: −10.25 to −5.70, P < 0.00001, 2 studies; CHM vs. antidepressants: mean difference: 0.01, 95% CI: −0.28 to 0.30, P = 0.95, 7 studies). CHM were associated with less adverse events than antidepressants, and adding CHM to antidepressants reduced adverse events. Despite the overall positive results, due to the small number of studies with sufficient methodological quality, it is premature to accurately conclude the benefits and risks of CHM for depression.