The effectiveness and safety of herbal medicine on suicidal behavior: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND: Suicide is the leading cause of death worldwide. Herbal medicine (HM) has been reported to be related to clinical improvement of some risk factors for suicide including depression. This systematic review aimed to comprehensively investigate the effectiveness and safety of HM on suicidal behaviors. METHODS: Fifteen electronic databases were searched to search relevant intervention studies, up to September 2022. The methodological quality of the included studies was assessed using the modified Cochrane risk-of-bias tool. In the included studies, outcome on suicidal behavior were analyzed, and the effect sizes were presented as mean differences (MDs) or risk ratios (RRs) with their 95% confidence intervals (CIs) through meta-analysis. The strength of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. RESULTS: A total of 13 randomized controlled trials (RCTs) were included in this review. Two RCTs of HM in patients with suicidal behavior found significant benefits of HM as an adjunct to fluoxetine or cognitive therapy in improving symptoms of depression. In 11 RCTs of HM in patients with other conditions, there was no statistically significant difference between HM and antidepressants in cognitive disturbance (MD, 0.12; 95% CIs, −0.20 to 0.45), a subscale of the Hamilton Rating Scale for Depression (HAMD), and suicidal ideation (0.18; −0.16 to 0.53), an item of HAMD. The overall quality of the included studies was poor. The strength of evidence assessed by GRADE was low or very low. CONCLUSIONS: Though some of the studies reported significant benefits of HM in improving suicidal behavior in patients with depression, further clarification on some unsolved questions is needed in future well-designed clinical trials.