Lorazepam and diazepam impair true, but not false, recognition in healthy volunteers.
RATIONALE: The deleterious effects of benzodiazepine on memory are well documented. However, their effects on false memories are unknown. OBJECTIVE: The aim of this study was to investigate the effects of lorazepam and diazepam on false memories and related states of awareness in healthy volunteers. METHODS: The Deese/Roediger-McDermott procedure was used in 36 healthy volunteers randomly assigned to one of three parallel groups (placebo, diazepam 0.3 mg/kg, lorazepam 0.038 mg/kg). Subjects studied lists of words semantically related to a non-presented theme word (critical lure). On a recognition memory task with both previously presented words and non presented critical lures, they were asked to give Remember, Know or Guess responses to items that were recognized on the basis of conscious recollection, familiarity, or guessing, respectively. RESULTS: The proportions of studied words correctly recognized and the proportions of Remember responses associated with true recognition were lower in the benzodiazepine groups than in the placebo group. In contrast, benzodiazepines did not significantly influence the proportions of critical lures falsely recognized or the proportions of Remember responses associated with false recognition. CONCLUSION: These results indicate that diazepam and lorazepam impair conscious recollection associated with true, but not false, memories.