THE AMNESIC ACTION OF BENZODIAZEPINES IN MAN

Benzodiazepines (BZs) may induce a massive but transient amnesia they affect the acquisition of new information, whereas retrieval of alread y learned information is unimpaired. As BZs can also be sedative, ther e is a question as to whether the amnesic effect is independent from t he sedative effect. Although the comparison between these two effects depends on the methods used, there may well be at least a partial diss ociation between amnesia and sedation: i) although BZs have the same s edative effect as barbiturates, only the BZs have an amnesic effect; i i) BZs as similar as oxazepam and lorazepam can lead to a similar seda tion but a different amnesia; iii) the amnesic effect can be dissociat ed temporally from the sedative effect; iv) flumazenil antagonises but not synchronously the sedation and amnesia induced by diazepam; v) th e tolerance for sedation is greater than that for amnesia. Thus BZs ap pear to have a specific amnesic effect, not uniquely secondary to thei r sedative powers, but increased by them. Practical and fundamental im plications of this dissociation of effects are to be considered.