Nutritional and herbal supplements for anxiety and anxiety-related disorders: systematic review.
Level 1 - systematic review of randomized trials
Systematic review of predominantly randomized controlled trials (21 of 24 included studies).
PubMed 20929532 · doi:10.1186/1475-2891-9-42
What was done
A systematic review was conducted by searching MEDLINE/PubMed and EBSCO without date restrictions for English-language clinical studies in humans evaluating nutritional and herbal supplements for anxiety and anxiety-related conditions. Extracted variables included study design, sample population, intervention, control, treatment duration, outcomes, direction of effect, and adverse events.
What was found
The review included 24 studies (21 randomized controlled trials and 3 open-label, uncontrolled studies) encompassing 2,619 participants (1,786 patients diagnosed with anxiety or depression and 877 healthy volunteers experiencing situational or trait anxiety). High heterogeneity and low study counts per supplement precluded formal meta-analysis. Positive direction of evidence was reported in 71% of randomized controlled trials (15 of 21). Side effects were mild to moderate. Strongest evidence was reported for extracts of passionflower or kava and combinations of L-lysine and L-arginine; St. John's wort monotherapy showed insufficient evidence.
Why it matters
This review synthesizes the clinical trial evidence for complementary anxiolytic therapies, helping clinicians and patients identify which specific natural products have randomized trial support.
Limits
A formal meta-analysis could not be conducted due to substantial heterogeneity across supplements and outcome measures. Search criteria were restricted to English-language publications. The analysis pooled trials in clinically diagnosed populations with trials in healthy volunteers undergoing acute stressors.
Cited by
- contradicts St. John's wort has been shown to significantly improve both depression and anxiety.