TIME-COURSE OF THE EFFECTS OF DIAZEPAM AND LORAZEPAM ON PERCEPTUAL PRIMING AND EXPLICIT MEMORY

The effects of diazepam and lorazepam on explicit memory and perceptua l priming were studied 50, 130 and 300 min after drug administration. Sixty healthy volunteers were randomly assigned to one of five paralle l groups (placebo, diazepam 0.2 or 0.3 mg/kg, lorazepam 0.026 or 0.038 mg/kg). The corresponding doses of ben zodiazepines exerted a similar negative effect on explicit performance. Lorazepam markedly impaired priming performance, whereas the effect of diazepam was intermediate b etween that of placebo and that of lorazepam 0.038 mg/kg. The impairme nt was maximal at the theoretical peak plasma concentration. Contamina tion by explicit memory could account for the decrease in priming perf ormance observed in the diazepam groups.