Cognitive Effects of Exogenous Melatonin Administration in Elderly Persons

Given that circadian rhythm disruption is associated with impairments in cognitive performance similar to those found in age-related cognitive decline, the authors investigated whether exogenous melatonin administration would improve cognitive functioning in healthy elderly subjects. This double-blind, placebo-controlled pilot study assigned 26 healthy elderly subjects to receive either melatonin 1 mg or placebo nightly for 4 weeks. Participants completed a sleep questionnaire and a battery of cognitive tests at baseline and at 4 weeks. Melatonin administration improved reported morning “restedness” and sleep latency after nocturnal awakening, and also improved scores on the California Verbal Learning Test–interference subtest. Melatonin administration at a dose of 1 mg nightly may be effective in improving certain aspects of cognitive functioning and subjective reports of sleep quality in elderly subjects. It may prove to be a useful therapeutic agent in the treatment of age-related cognitive decline.