Effects on memory following a single oral dose of diazepam

The effects of diazepam on learning and memory were investigated in a double-blind study of 28 Uruguayan university women who were randomly assigned to four treatments, seven subjects each: placebo, 0.1, 0.2, and 0.3 mg/kg diazepam orally. Subjects were presented with five uncategorized and categorized word lists, a 12-digit number list, and a tonal discrimination test, before and up to 200 min after treatment. Immediate and delayed recall were tested. Performance of the 0.1 mg/kg diazepam group did not show significant differences from placebo in any of the tests. For the 0.2 dose group, marginal impairments were noted at 60 min followed by full recovery at 190 min. On the contrary, 0.3 mg/kg diazepam produced significant impairments on immediate and delayed recall, with marginal impairments still evident at 190 min. The finding that diazepam did not impair performance on a tonal discrimination test provided some evidence that memory impairments did not result from failures in general alertness.