An Alternative Treatment for Anxiety: A Systematic Review of Human Trial Results Reported for the Ayurvedic Herb Ashwagandha (Withania somnifera)

Abstract

Objective: To assess existing reported human trials of Withania somnifera (WS; common name, ashwagandha) for the treatment of anxiety. Design: Systematic review of the literature, with searches conducted in PubMed, SCOPUS, CINAHL, and Google Scholar by a medical librarian. Additionally, the reference lists of studies identified in these databases were searched by a research assistant, and queries were conducted in the AYUSH Research Portal. Search terms included ''ashwagandha,'' ''Withania somnifera,'' and terms related to anxiety and stress. Inclusion criteria were human randomized controlled trials with a treatment arm that included WS as a remedy for anxiety or stress. The study team members applied inclusion criteria while screening the records by abstract review. Intervention: Treatment with any regimen of WS. Outcome measures: Number and results of studies identified in the review. Results: Sixty-two abstracts were screened; five human trials met inclusion criteria. Three studies compared several dosage levels of WS extract with placebos using versions of the Hamilton Anxiety Scale, with two demonstrating significant benefit of WS versus placebo, and the third demonstrating beneficial effects that approached but did not achieve significance ( p = 0.05). A fourth study compared naturopathic care with WS versus psychotherapy by using Beck Anxiety Inventory (BAI) scores as an outcome; BAI scores decreased by 56.5% in the WS group and decreased 30.5% for psychotherapy ( p < 0.0001). A fifth study measured changes in Perceived Stress Scale (PSS) scores in WS group versus placebo; there was a 44.0% reduction in PSS scores in the WS group and a 5.5% reduction in the placebo group ( p < 0.0001). All studies exhibited unclear or high risk of bias, and heterogenous design and reporting prevented the possibility of meta-analysis. Conclusions: All five studies concluded that WS intervention resulted in greater score improvements (significantly in most cases) than placebo in outcomes on anxiety or stress scales. Current evidence should be received with caution because of an assortment of study methods and cases of potential bias.

Herbal medicines in the treatment of psychiatric disorders: 10‐year updated review

“…In human studies, a recent systematic review by Pratte, Nanavati, Young, and Morley (2014) discussed previous studies of ashwagandha on anxiety/stress outcomes. They identified five human RCTs with 400 participants.…”

GABA‐modulating phytomedicines for anxiety: A systematic review of preclinical and clinical evidence

“…In human studies, a recent systematic review (Pratte, Nanavati, Young, & Morley, 2014) captured all previous studies of W. somnifera with anxiety/stress outcomes (e.g., Auddy et al, 2008;Chandrasekhar et al, 2012;Chengappa et al, 2013). This identified five human RCTs with 400 participants (range = 39-130).…”

Effects of an Adaptogenic Extract on Electrical Activity of the Brain in Elderly Subjects with Mild Cognitive Impairment: A Randomized, Double-Blind, Placebo-Controlled, Two-Armed Cross-Over Study

“…One of the constituents of Adaptra ® Forte, Withania somnifera, is reported to be effective in the treatment of anxiety. According to [46], five clinical studies concluded that W. somnifera intervention resulted in greater score improvements (significantly, in most cases) than placebo in outcomes on anxiety or stress scales. Broad evidence from preclinical studies indicates a possible anxiolytic and/or anti-depressive activity of constituents from W. somnifera [26,47].…”