Safety and efficacy of Withania somnifera for anxiety and insomnia: Systematic review and meta-analysis

Objective: Despite the historical neurological use of Withania somnifera, limited evidence supports its efficacy for conditions like anxiety and insomnia. Given its known anti-stress properties, this review evaluated its safety and efficacy for anxiety and insomnia. Methods: We searched Medline, Cochrane Library, and Google Scholar until August 2023 for randomized controlled trials (RCTs) comparing W. somnifera to placebo in patients with anxiety and/or insomnia. Outcome measures included changes in anxiety levels via the Hamilton Anxiety Scale (HAM-A), Sleep Onset Latency (SOL), Total Sleep Time (TST), Wake After Sleep Onset (WASO), Total Time in Bed (TIB), Sleep Efficiency (SE), and Pittsburgh Sleep Quality Index (PSQI) score. We utilized a random-effect model for pooling Mean Differences (MD) with a 95% Confidence Interval (CI). Heterogeneity was assessed through sensitivity and subgroup analysis, and the quality of RCTs was evaluated using the Cochrane revised risk of bias tool. Results: Pooled results from five RCTs (n = 254) demonstrated that W. somnifera significantly reduced HAM-A scores (MD = -5.96; [95% CI -10.34, -1.59]; P = 0.008; I-2 = 98%), as well as sleep parameters such as SOL, TST, PSQI, and SE, but not WASO and TIB. Conclusion: While W. somnifera extracts yielded promising results, further research with larger sample sizes is needed to confirm its effects on anxiety and insomnia.