STATE-DEPENDENT RETRIEVAL AND MIDAZOLAM

This experiment investigated the phenomenon of state-dependent retriev al with midazolam by comparing performance after midazolam + placebo w ith that after reversal with the benzodiazepine antagonist flumazenil, in tests of explicit and semantic memory and judgements of recency. T he subjects completed analogue rating scales and psychomotor tests to provide measures of sedation. Midazolam (0.05 mg/kg) impaired recall a nd recognition of pictures and performance in the digit-symbol substit ution task. There were no significant state-dependent effects with thi s dose. Midazolam (0.075 mg/kg) impaired recall and recognition of wor ds and pictures and recognition of coloured slides of complex scenes. There were significant state-dependent effects on all the recognition tests, i.e. the group tested after reversal with flumazenil (0.5 mg) p erformed worse than that tested after placebo. Midazolam (0.075 mg(kg) also impaired recency judgements and performance in the number cancel lation and digit-symbol substitution tests, but there were no state-de pendent effects in these tests. To determine whether subjects had insi ght into their memory impairments, for each task they were asked to ra te on an analogue scale whether they thought their memory would be 'be tter or worse than usual'. Those tested with midazolam (0.075 mg/kg) s howed no insight into their memory impairments and there were negative correlations between actual and estimated performance. However those reversed with flumazenil were aware their memory was worse than usual and had positive correlations between actual and estimated performance , similar to those shown by subjects tested undrugged.