Melatonin treatment in individuals with intellectual disability and chronic insomnia: a randomized placebo-controlled study.

BACKGROUND: While several small-number or open-label studies suggest that melatonin improves sleep in individuals with intellectual disabilities (ID) with chronic sleep disturbance, a larger randomized control trial is necessary to validate these promising results. METHODS: The effectiveness of melatonin for the treatment of chronic sleep disturbance was assessed in a randomized double-blind placebo-controlled trial with 51 individuals with ID. All of these individuals presented with chronic ideopatic sleep disturbance for more than 1 year. The study consisted of a 1-week baseline, followed by 4 weeks of treatment. Parents or other caregivers recorded lights off time, sleep onset time, night waking, wake up time and epileptic seizures. Endogenous melatonin cycle was measured in saliva before and after treatment. RESULTS: Compared with placebo, melatonin significantly advanced mean sleep onset time by 34 min, decreased mean sleep latency by 29 min, increased mean total sleep time by 48 min, reduced the mean number of times the person awoke during the night by 0.4, decreased the mean duration of these night waking periods by 17 min and advanced endogenous melatonin onset at night by an average of 2.01 h. Lights off time, sleep offset time and the number of nights per week with night waking did not change. Only few minor or temporary adverse reactions and no changes in seizure frequency were reported. CONCLUSIONS: Melatonin treatment improves some aspects of chronic sleep disturbance in individuals with ID.