Polysomnographic study of the effect of melatonin on sleep in elderly patients with chronic primary insomnia

The effect of 3-mg melatonin capsules p.o. on sleep in ten elderly patients suffering from chronic primary insomnia was assessed by polysomnographic recordings. In general, melatonin significantly reduced wake time after sleep onset and increased total sleep time and sleep efficiency during the 2-week treatment period. In five of the ten patients treated with melatonin, the increase in total sleep time was clinically significant. Side effects were absent during the period of drug administration. A slight increase of power density in the delta and the theta regions was found during the early phase (i.e. nights 4–5) of melatonin administration, whereas the opposite changes were observed at a late phase of treatment (i.e. nights 15–16). No strict correlation was found between prior 6-sulphatoxymelatonin levels in urine and subsequent sleep improvement after receiving melatonin. Our results further support the proposal that melatonin is beneficial for sleep disturbances in elderly insomniacs.