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The effects of a single dose of lorazepam on behavioural and procedural learning
thesisposted on 2023-05-27, 17:13 authored by Oldmeadow, Meredith Alison
Research shows that lorazepam impairs episodic memory and perceptual priming, with preservation of some types of procedural memory. Behavioural learning has been reported as impaired by lorazepam, however the mechanism of action is unclear. The objectives of this study were to compare the effects of lorazepam on behavioural learning and explicit and implicit memory tasks, whilst controlling for state dependent learning effects and the amount of behavioural learning. Sixty participants received lorazepam 2.5 mg (L) or placebo (P) orally in two assessment sessions a week apart (four groups n=15: LL, LP, PP, PL). Pre-drug and post-drug neuropsychological assessment in session 1 comprised the Rey Auditory Verbal Leaming Test (RAVLT), Controlled Oral Word Association (COWA), Digit Span and Word-Stem Completion Task. In sessions 1 and 2, procedural learning was measured by the Serial Reaction Time Task (SRTT) and behavioural learning by a behavioural learning task (BLT) The BLT is a computer-aided vicarious exposure treatment for obsessive-compulsive disorder which models exposure and response prevention, using learning to criterion. BLT learning measures were derived from recording of human-computer interactions. Lorazepam impaired episodic memory (RAVLT) and perceptual priming (Word-Stem Completion). On the SRTT, Lorazepam slowed reaction time but rate of learning and accuracy, indices of procedural learning, were not impaired. On the BLT, Lorazepam increased time to criterion; carryover effects of learning between sessions 1 and 2 were substantially reduced in the LL and LP groups. High level learning in these groups was reduced in session 2, relative to a first session on placebo. State dependent learning effects were not found. Lorazepam impaired behavioural learning through impairment of explicit memory and possibly due to its direct impairment of insight learning, which has been implicated in behavioural therapies. Leaming strategies based on spared procedural memory may assist clinical participants taking benzodiazepines needing to learn behavioural skills.
Rights statementCopyright 2006 the author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s). Thesis (PhD)--University of Tasmania, 2006. Includes bibliographical references