Effectiveness of Valerian on insomnia: a meta-analysis of randomized placebo-controlled trials.
Level 1 - systematic review of randomized trials
Meta-analysis of randomized controlled trials
PubMed 20347389 · doi:10.1016/j.sleep.2009.12.009
What was done
Systematic review and meta-analysis of randomized clinical trials comparing valerian preparations to placebo for insomnia across Medline, Cochrane Library, Embase, and Biosis. Evaluated outcomes included subjective sleep-quality improvement (yes/no), visual analog scale sleep-quality scores (SQS), and sleep latency time (LT) in minutes. Three meta-analyses were conducted using inverse-variance weighted random effects models, with heterogeneity assessed via the Q-statistic and subgroup analysis, and publication bias checked via funnel plot.
What was found
Eighteen RCTs were included (8 scored 5 on Jadad's scale). Valerian showed no statistically significant difference versus placebo for sleep latency time (mean difference: 0.70 min; 95% CI, -3.44 to 4.83) or visual analog sleep-quality scores (standardized mean difference: -0.02; 95% CI, -0.35 to 0.31). Treatment with valerian showed a statistically significant relative risk of subjective sleep-quality improvement of 1.37 (95% CI, 1.05-1.78). Heterogeneity was present in all three meta-analyses but reduced in subgroup analyses; no publication bias was detected.
Why it matters
This review demonstrates that while valerian may show a modest benefit on subjective, binary self-reports of sleep quality, it does not demonstrate efficacy on quantitative or continuous measures of sleep latency and quality.
Limits
Total participant sample size and specific valerian preparations/dosages are not reported in the abstract. Significant heterogeneity was present across the included trials, and positive findings were restricted solely to subjective binary measures rather than objective or quantitative metrics.
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