Effect of melatonin on sleep microstructure: preliminary results in healthy subjects.

The ability of melatonin (MLT) to potentiate the effects of gamma-aminobutyric acid and the benzodiazepines has been demonstrated repeatedly in animal models, and recent experimental data favored the hypothesis that MLT, given together with threshold doses of benzodiazepines, could significantly improve the quality of sleep. This preliminary study was designed to compare the effects of MLT (100 mg) with those of a benzodiazepine hypnotic [triazolam (TRI) 0.125 mg] and to explore the effects of a combination of MLT and TRI at a low dose in healthy volunteers. No significant changes in the classical polysomnographic variables were observed following MLT, TRI and MLT + TRI, whereas MLT and especially MLT + TRI resulted in significant modulation of some microstructural parameters. These changes were paralleled by ameliorated subjective sleep quality. A combination of MLT and low benzodiazepine doses could avoid the residual, dose-related benzodiazepine effects.