Melatonin for Shift Work Sleep Disorder

Finding: Across 9 melatonin trials, melatonin (1-10 mg) after a night shift increased daytime sleep length by a mean of 24 minutes (95% CI 9.8 to 38.9; 7 trials, 263 participants) but gave sleep onset latency no different from placebo (MD 0.37 min, 95% CI -1.55 to 2.29) and did not improve on-shift alertness, all on low-quality evidence.

Finding: This narrative systematic review of 10 clinical trials concluded melatonin (1-10 mg) decreased daytime sleepiness, shortened sleep onset latency, reduced night-time awakenings, increased total sleep period and improved daytime attention, with low adverse effects, but pooled no effect size and rated the evidence as SIGN grade B / level 1- (CONSORT scores 6.0-13.7).

Finding: In 86 shift-work nurses, 5 mg melatonin 30 minutes before sleep significantly reduced sleep onset latency versus both placebo and baseline, but had no meaningful effect on total sleep time, with no adverse effects reported.

Finding: Among 39 shift workers with difficulty falling asleep, 3 mg melatonin increased sleep efficiency from 82.1% to 85.5% and shortened sleep onset latency (0.27 to 0.20 h), while effects on total sleep time and wakefulness after sleep onset were not statistically significant.

Finding: In 24 emergency medicine residents (replicated crossover), 3 mg melatonin produced no significant between-group difference in sleep efficiency versus placebo (daytime sleepiness fell within the melatonin arm, P=0.003, but not relative to placebo), and the authors concluded melatonin has only limited benefit on sleep quality.

Finding: In 18 emergency physicians, 10 mg sublingual melatonin did not significantly improve the primary gestalt day-sleep (P=0.3) or night-alertness measures, with authors concluding only a possible modest benefit (9 of 13 secondary comparisons favoured melatonin).