A randomized, double-blind, placebo-controlled crossover study of the effect of exogenous melatonin on delayed sleep phase syndrome
Abstract
OBJECTIVE: The effects of exogenous melatonin on sleep, daytime sleepiness, fatigue, and alertness were investigated in 22 patients with delayed sleep phase syndrome whose nocturnal sleep was restricted to the interval from 24:00 to 08:00 hours. This study was a randomized, double-blind, placebo-controlled crossover trial. Subjects received either placebo or melatonin (5 mg) daily for 4 weeks, underwent a 1-week washout period, and then were given the other treatment for an additional 4 weeks. Patients could take the melatonin between 19:00 and 21:00 hours, which allowed them to select the time they felt to be most beneficial for the phase-setting effects of the medication.
METHODS: Two consecutive overnight polysomnographic recordings were performed on three occasions: at baseline (before treatment), after 4 weeks of melatonin treatment, and after 4 weeks of placebo treatment.
RESULTS: In the 20 patients who completed the study, sleep onset latency was significantly reduced while subjects were taking melatonin as compared with both placebo and baseline. There was no evidence that melatonin altered total sleep time (as compared with baseline total sleep time), but there was a significant decrease in total sleep time while patients were taking placebo. Melatonin did not result in altered scores on subjective measures of sleepiness, fatigue, and alertness, which were administered at different times of the day. After an imposed conventional sleep period (from 24:00 to 08:00),…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 22 participants or records.
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