Abstract
The residual effects of benzodiazepines on attention and psychomotor performance have been extensively documented. However, there are very few studies comparing the action of benzodiazepines and non-benzodiazepine (imidazopiridines and cyclopirrolones) compounds on these parameters. The aim of this work was to assess the residual effects on diurnal wakefulness in healthy volunteers after nocturnal administration of a single dose of diazepam (10 mg), zolpidem (10 mg), zopiclone (7.5 mg), gamma-amino-ß-hydroxybutyrate (500 mg), or placebo. Drugs were given at 22 h (half-hour before bedtime), in a double-blind fashion according to an extended Youden Square design. Subjects slept for six consecutive nights in the sleep laboratory (habituation, baseline, drug 1, placebo, drug 2, placebo). The morning after nocturnal dosing, psychomotor performance was measured using a simple visuomotor reaction time (RT) task, with two stimulation patterns (isochronus and stochastic). The results indicated an absence of residual effects on attention after zopiclone and zolpidem intake. Likewise, administration of diazepam did not provoke a significant deterioration in the attention level. GABOB was the only drug which produced a marked decrease in the isochronus RT after 9 hours of its administration, in comparison to its baseline, not appreciating any significant modification in the stochastic RT. It is emphasized that residual impairment on RT following intake of hypnotics should be considered on the basis of the stimulation pattern used (stochastic vs isochronus) during vigilance assessment.
