The sedative, amnestic, and performance disruptive effects of benzodiazepine (Bz) receptor selective and non-selective hypnotics were studied in 23 healthy, normal subjects, aged 26.8 +/- 1.0 years. Triazolam (0.25 and 0.50 mg), zolpidem (10 and 20 mg) and placebo were administered, double-blind, at bedtime in a repeated measures design. During an awakening 90 min later (at approximate peak concentration of each drug) a 30-min performance battery which included memory, vigilance, and psychomotor tasks was completed. Each drug and dose impaired memory (both immediate and delayed), vigilance, and psychomotor performance relative to placebo. Among active drugs impairment was greatest with zolpidem 20 mg, next triazolam 0.50 mg, then zolpidem 10 mg, and finally triazolam 0.25 mg. Next morning delayed recall was also impaired by all drugs and doses (i.e. anterograde amnesia). The amnestic and performance-disruptive effects paralleled the relative hypnotic effects of the drugs and doses. No receptor selectivity in these pharmacodynamic effects was observed.