Effects of the benzodiazepine lorazepam on monitoring and control processes in semantic memory.

Lorazepam has been repeatedly shown to induce memory impairments. The effects of this benzodiazepine on the processes involved in the strategic regulation of memory accuracy have not as yet been explored. An experimental procedure that delineates the role of monitoring and control processes was used. Fifteen lorazepam and 15 placebo subjects were examined using a semantic memory task that combined both a forced- and a free-report option and a no-incentive and an incentive condition. Memory accuracy was lower in the lorazepam than in the placebo group. Lorazepam impaired control sensitivity (the extent to which volunteering of answers is affected by the confidence judgments). While the absolute aspect of monitoring was impaired (calibration scores), both the discriminative aspect (the ability to distinguish between correct and incorrect answers) and the response criterion setting (the confidence threshold set for volunteering a report) were spared. The pharmacological dissociation between monitoring effectiveness and control sensitivity indicates that these two components involve distinct processes.