Treatment of primary insomnia with melatonin: a double-blind, placebo-controlled, crossover study

To assess the hypnotic effect of melatonin in patients with primary insomnia. Ten patients (mean age 50 yr, range 30-72 yr) who met the DSM-IV criteria for primary insomnia received, in random order, 0.3 mg of melatonin, 1.0 mg of melatonin or placebo 60 minutes before bedtime. A crossover design was used so that each patient received each of the 3 treatments for a 7-day period (with a 5-day washout period between). After each 7-day treatment, night time electroencephalographic (EEG) records were collected, and each morning, subjects completed sleep logs and analogue-visual scales to document the amount and subjective quality of sleep. There were no significant differences in sleep EEG, the amount or subjective quality of sleep or side effects between the placebo, 0.3-mg melatonin or 1.0-mg melatonin treatments. Melatonin did not produce any sleep benefit in this sample of patients with primary insomnia.