Different effects of lorazepam and diazepam on perceptual integration

Recent research has established the detrimental effect of lorazepam, a benz odiazepine, on both implicit and explicit memory. Furthermore, lorazepam is known to affect perceptual integration. Diazepam, on the other hand, thoug h being a benzodiazepine too, only impairs explicit memory, leaving implici t memory fairly intact. Little is known about the effect of diazepam on per ceptual integration. The present study aimed at filling in this gap, by com paring the effects of lorazepam and diazepam on the detection of discontinu ities in random-shaped outlines. In line with previous findings, the result s in a lorazepam-treated group were quite different from the results in a p lacebo-treated group. The results in a diazepam-treated group were analogou s to the results in the placebo-treated group and different from the result s in the lorazepam-treated group. This shows that lorazepam and diazepam di ffer, not only with respect to their effect on implicit memory, but also wi th respect to their effect on perceptual integration. It is argued that thi s bears important consequences for memory research that makes use of a phar macological dissociation rationale. (C) 2001 Elsevier Science Ltd. All righ ts reserved.