Psychopharmacology

, Volume 128, Issue 2, pp 139–149

Effects of oxazepam and lorazepam on implicit and explicit memory: evidence for possible influences of time course

  • S. H. Stewart
  • George F. Rioux
  • John F. Connolly
  • Sandra C. Dunphy
  • Michael D. Teehan
ORIGINAL INVESTIGATION

DOI: 10.1007/s002130050119

Cite this article as:
Stewart, S., Rioux, G., Connolly, J. et al. Psychopharmacology (1996) 128: 139. doi:10.1007/s002130050119

Abstract

The effects of oxazepam (30 mg), lorazepam (2 mg), and placebo on implicit and explicit memory were studied in two testing cycles, 100 and 170 min after drug administration. Thirty healthy volunteers were randomly assigned to one of three groups (placebo, oxazepam, or lorazepam) in a double-blind, independent groups design. Drug groups were equivalent prior to drug administration on a variety of cognitive measures. Following drug administration, both oxazepam and lorazepam equally impaired performance on a cued-recall explicit memory task relative to placebo, at both testing cycles. Relative to placebo, lorazepam markedly impaired priming on a word-stem completion implicit memory task, at both testing cycles. Consistent with previous work, oxazepam failed to produce impairments in priming on the word-stem completion task at 100 min post-drug administration. However, oxazepam was found significantly to impair priming on this latter task relative to placebo, at close to theoretical peak plasma concentration (i.e., 170 min post-drug administration). Explanations for the observed detrimental effect of oxazepam on implicit memory task performance are considered, including: possible time-dependent effects related to the relative rate of absorption of these two benzodiazepines (BZs); and potential contamination of the implicit memory task by explicit memory strategies during the second testing cycle.

Key words Benzodiazepine Explicit memory Implicit memory Lorazepam Oxazepam Priming 

Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • S. H. Stewart
    • 1
  • George F. Rioux
    • 1
  • John F. Connolly
    • 1
  • Sandra C. Dunphy
    • 1
  • Michael D. Teehan
    • 2
  1. 1.Department of Psychology, Dalhousie University, Life Sciences Centre, 1355 Oxford Street, Halifax, Nova Scotia, Canada B3H 4J1CA
  2. 2.Department of Psychiatry, Dalhousie University, Life Sciences Centre, 1355 Oxford Street, Halifax, Nova Scotia, Canada B3H 4J1CA

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