Effects of zolpidem and zopiclone on cognitive and attentional function inyoung healthy volunteers: An event-related potential study

The effects of zolpidem and zopiclone, non-benzodiazepine ultra-short-actin g hypnotics, on cognitive function and vigilance level were investigated in the morning following nocturnal administration using event-related potenti als (ERP) and a sleep latency test (SLT). Zopiclone significantly shortened the sleep latency the following morning, whereas zolpidem did not, perhaps due to the difference in the elimination half-lives between the compounds. No significant effect was observed for either drug on the ERP indices, inc luding the P3, mismatch negativity and negative difference components. At a clinically prescribed dosage these sleep inducers have no remarkable effec t on cognitive or attentional functions but increase sleepiness of the subj ects.