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Full Title: Melatonin for Treatment of Sleep Disorders

November 2004

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Structured Abstract

Objectives: To review the effectiveness of melatonin for the treatment of sleep disorders; the safety, pharmacology and mechanisms of action of exogenous melatonin; and the link between endogenous melatonin and circadian rhythms.

Data Sources: Studies were selected from the following electronic databases: MEDLINE®, PreMEDLINE®, EMBASE, PubMed®, CAB Health®, CINAHL®, AMED®, Cochrane Central Register of Controlled Trials®, Cochrane Complementary Medicine Field Registry®, Science Citation Index®, Biological Abstracts®, International Pharmaceutical Abstracts®, NLM Gateway®, OCLC papers First and Proceedings First®, TOXLINE®, Registry of Toxic Effects of Chemical Substances (RTECS)®. Data were also obtained from register of ongoing trials.

Review Methods: Studies were selected for particular questions of the review according to predetermined, question-specific inclusion criteria. Only English-language reports were included in the review. The quality of studies was assessed using either the Jadad Scale for Quality Assessment of Randomized-Controlled Trials or the Downs and Black Checklist for Quality Assessment of Non-Randomized Controlled Trials. Allocation concealment in the randomized controlled trials was also assessed. Data were analyzed using a Random Effects Model. All results were reported with 95 per cent confidence intervals. Sources of heterogeneity were assessed using the I-squared statistic, and publication bias was assessed using the Funnel Plot approach, the Rank Correlation Test, the Graphical Test, and the Trim and Fill Method.


Effectiveness of Exogenous Melatonin:
  • People with a Primary Sleep Disorder: Melatonin decreased sleep onset latency, significantly in people with delayed sleep phase syndrome and marginally in patients with insomnia. There was no effect on sleep efficiency.
  • People with a Secondary Sleep Disorder: Melatonin had no effect on sleep onset latency, but it increased sleep efficiency.
  • People Suffering from Sleep Restriction: Melatonin had no effect on sleep onset latency or sleep efficiency.

Safety of Exogenous Melatonin: There was no evidence of adverse effects of melatonin with short-term use.


  • Melatonin is not effective in treating most primary sleep disorders with short-term use, although some evidence suggests that melatonin is effective in treating delayed sleep phase syndrome with short-term use.
  • Melatonin is not effective in treating most secondary disorders with short-term use.
  • Melatonin is not effective in alleviating the sleep disturbance aspect of jet lag and shift-work disorder.
  • Melatonin is safe with short-term use.

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Melatonin for Treatment of Sleep Disorders

Evidence-based Practice Center: University of Alberta
Topic Nominator: National Center for Complementary and Alternative Medicine, National Institutes of Health (NIH)
Topic Funder: National Institutes of Health (NIH)

Current as of November 2004


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