Efficacy of melatonin for chronic insomnia: Systematic reviews and meta-analyses.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 36179487 · doi:10.1016/j.smrv.2022.101692
What was done
Authors conducted a systematic review and meta-analysis across Ovid-MEDLINE, EMBASE, and Cochrane Library through November 2020 to evaluate melatonin versus placebo or other hypnotic agents for chronic insomnia. Analyzed outcomes were sleep onset latency, total sleep time, sleep efficiency, sleep quality, and quality of life. The search identified 24 randomized controlled trials (all compared against placebo; 4 addressed comorbid insomnia). Due to heterogeneity, subgroup analyses were stratified by age group.
What was found
The abstract provides directional findings without numerical values, effect sizes, or confidence intervals. In non-comorbid insomnia, melatonin was significantly effective for sleep onset latency and total sleep time exclusively in children and adolescents; it was not significantly effective for sleep onset latency, total sleep time, or sleep efficiency in adults. In comorbid insomnia, melatonin significantly improved sleep onset latency across all age groups, though only one trial evaluated adults.
Why it matters
This review indicates that melatonin's efficacy for chronic insomnia is primarily supported in pediatric populations, calling into question its broad empirical support as a first-line agent for adult non-comorbid insomnia.
Limits
The abstract reports no numerical estimates, standard errors, or p-values. Heterogeneity was present among the included studies. No active-comparator trials against other hypnotic agents were identified, and data on adult comorbid insomnia relied on a single study.
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