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, 8 (5), e63773

Meta-analysis: Melatonin for the Treatment of Primary Sleep Disorders


Meta-analysis: Melatonin for the Treatment of Primary Sleep Disorders

Eduardo Ferracioli-Oda et al. PLoS One.


Study objectives: To investigate the efficacy of melatonin compared to placebo in improving sleep parameters in patients with primary sleep disorders.

Design: PubMed was searched for randomized, placebo-controlled trials examining the effects of melatonin for the treatment of primary sleep disorders. Primary outcomes examined were improvement in sleep latency, sleep quality and total sleep time. Meta-regression was performed to examine the influence of dose and duration of melatonin on reported efficacy.

Participants: Adults and children diagnosed with primary sleep disorders.

Interventions: Melatonin compared to placebo.

Results: Nineteen studies involving 1683 subjects were included in this meta-analysis. Melatonin demonstrated significant efficacy in reducing sleep latency (weighted mean difference (WMD) = 7.06 minutes [95% CI 4.37 to 9.75], Z = 5.15, p<0.001) and increasing total sleep time (WMD = 8.25 minutes [95% CI 1.74 to 14.75], Z = 2.48, p = 0.013). Trials with longer duration and using higher doses of melatonin demonstrated greater effects on decreasing sleep latency and increasing total sleep time. Overall sleep quality was significantly improved in subjects taking melatonin (standardized mean difference = 0.22 [95% CI: 0.12 to 0.32], Z = 4.52, p<0.001) compared to placebo. No significant effects of trial duration and melatonin dose were observed on sleep quality.

Conclusion: This meta-analysis demonstrates that melatonin decreases sleep onset latency, increases total sleep time and improves overall sleep quality. The effects of melatonin on sleep are modest but do not appear to dissipate with continued melatonin use. Although the absolute benefit of melatonin compared to placebo is smaller than other pharmacological treatments for insomnia, melatonin may have a role in the treatment of insomnia given its relatively benign side-effect profile compared to these agents.

Conflict of interest statement

Competing Interests: This study was partly funded by APIRE/Eli Lilly Psychiatric Research Fellowship (to MHB) and the AACAP/Eli Lilly Pilot Research Award (to MHB). There are no patents, products in development or marketed products to declare. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials.


Figure 1
Figure 1. Efficacy of Melatonin in Reducing Sleep Latency.
Forest plot depicting reduction of sleep latency in melatonin compared to placebo. Meta-analysis demonstrated a significant benefit of melatonin in reducing sleep latency. WMD = weighted mean difference; CI = confidence interval.
Figure 2
Figure 2. Efficacy of Melatonin in Increasing Total sleep Time.
Forest plot depicting change in total sleep time with melatonin compared to placebo treatment. Meta-analysis demonstrated a significant benefit of melatonin in increasing total sleep time. WMD = weighted mean difference; CI = confidence interval.
Figure 3
Figure 3. Effect of Melatonin on Sleep quality.
Forest plot depicts sleep quality with melatonin compared to placebo. Meta-analysis demonstrated a significant benefit of melatonin in improving sleep quality. SMD = standardized mean difference; CI = confidence interval.

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