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Abstract

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.

Item Type:	Thesis - PhD
Authors/Creators:	Oldmeadow, Meredith Alison
Keywords:	Lorazepam
Copyright Holders:	The Author
Copyright Information:	Copyright 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).
Additional Information:	Thesis (PhD)--University of Tasmania, 2006. Includes bibliographical references
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