The nature of lorazepam-induced amnesia.

The effect of lorazepam (2.5 mg) was assessed in two tests of short-term retention (digit-span and Benton Visual Retention), and in verbal learning and picture recognition tests. Lorazepam was without effect in a test of digit-span, but it impaired performance in the Benton Visual Retention and picture recognition tests. In the verbal learning test lorazepam caused a severe anterograde amnesia. Increasing arousal during the presentation of material partially overcame this effect, but also improved the performance of controls. Lorazepam-treated subjects were able to learn a backwards-reading task at a rate no different from controls. The deficits caused by lorazepam are similar to those that have been observed in patients with the amnesic syndrome.