Melatonin is effective for some sleep disorders

Question Is melatonin effective for insomnia and other sleep problems?

Synopsis The authors of this systematic review evaluated the role of melatonin in the treatment of different types of sleep problems in different types of patients. They performed a thorough search of the literature but limited the research to English language publications. Potential research was screened by two independent reviewers and the data were abstracted by one reviewer and then checked for accuracy by another. They included controlled clinical trials and reviewed all studies for quality using the established Jadad criteria. In normal sleepers, melatonin had a clinically insignificant effect on the time to sleep onset (sleep onset latency) or the amount of time actually spent asleep (sleep efficiency). Melatonin in doses of 1 mg to 3 mg caused an average 12.7 minutes' delay in onset of rapid eye movements (REM latency) compared with placebo. In patients with simple insomnia, melatonin helped adults to fall asleep an average 10.7 minutes faster (95% CI 3.7 to 17.6 min). Children had a better response, falling asleep an average 17 minutes faster. Melatonin was particularly effective in patients with delayed sleep phase syndrome, in which a person's circadian rhythm is misaligned without an external cause such as jet lag or shift work. In these patients, sleep onset was an average 38.8 minutes faster (27.3 to 50.3 min). Melatonin had no effect on sleep quality, wakefulness, total sleep time, or percentage of time spent in REM sleep. In patients with jet lag, melatonin did not decrease sleep onset latency or increase sleep efficiency, sleep quality, or the time spent in REM sleep, though it was effective in increasing the total sleep time. It had a similar effect as zolpidem in patients with jet lag in one study. Melatonin is not effective in patients with a secondary sleep disorder.

Bottom line Melatonin in doses from 0.1 mg to 10 mg is effective in helping adults and children who have difficulty falling asleep. It is particularly helpful in patients whose circadian rhythm is permanently off kilter (delayed sleep phase syndrome). It increases sleep length, but not sleep quality, in patients who perform shift work or who have jet lag.

Level of evidence 1a (see www.infopoems.com/levels.html). Systematic reviews (with homogeneity) of randomised controlled trials.