Delayed sleep phase syndrome response to melatonin

The actions of melatonin on the sleep-wake cycle were investigated by means of a randomised, double-blind, placebo-controlled trial in 8 subjects with a delayed sleep phase syndrome attending a sleep disorders clinic. In randomised order the subjects received placebo or melatonin 5 mg daily for 4 weeks with a 1 week washout period between the treatments. Drug or placebo was given at 2200 h, 5 h before the mean time of sleep onset determined by pretrial sleep logs. In all 8 subjects sleep onset time (mean advance 82 [range 19-124] min; p