Diazepam and learning: assessment of acquisition deficits.

Subjects treated with diazepam (0.3 mg/kg) showed significant reductions in performance on multiple-trial free recall, paired-associate learning, and serial learning tasks compared to placebo control subjects. The free recall task showed the largest drug effect with diazepam subjects failing in six acquisition trials to attain the level of performance achieved by placebo subjects on the first trial. Serial position curves in the serial learning task were changed by the diazepam treatment from their usual skewed form to symmetrical functions. Results indicate that diazepam exerts its greatest memory influence on the acquisition of new information.