title: Effects of lorazepam and oxazepam on perceptual and procedural memory functions.
abstract: BACKGROUND
  Lorazepam has been found to consistently impair performance on both episodic and perceptual priming tasks, whereas other benzodiazepines have shown perceptual priming to be preserved. However, it has recently been postulated that benzodiazepines may exert time-dependent effects on implicit memory processes after research findings indicated some benzodiazepines, other than lorazepam, impair performance on priming tasks when tested at the time of peak plasma concentration level after benzodiazepine administration.
  
  
  OBJECTIVE
  To compare time-dependent effects of lorazepam and oxazepam on implicit memory tasks, specifically perceptual priming and procedural learning.
  
  
  METHODS
  Thirty-three healthy female undergraduates were randomised to one of three time groups (pre-peak, peak, post-peak) and administered placebo, 2.5 mg lorazepam, and 30 mg oxazepam, in counterbalanced order, at 1-week intervals. Assessments included word-stem completion (perceptual priming) and rotary pursuit (procedural learning) tasks.
  
  
  RESULTS
  At all time intervals, lorazepam but not oxazepam significantly impaired perceptual priming but procedural learning was preserved under both drugs.
  
  
  CONCLUSIONS
  These findings are consistent with previous research showing a differential effect of lorazepam in impairing perceptual memory but the notion that benzodiazepines exert time-dependent effects on implicit memory processes was not supported.
authors.affiliation: School of Psychology, University of Tasmania, GPO Box 252-30, Hobart, Tasmania 7001, Australia. Janine.Martin@utas.edu.au
authors.forename: Janine
authors.initials: J
authors.lastname: Martin
authors.forename: Allison
authors.initials: A
authors.lastname: Matthews
authors.forename: Frances
authors.initials: F
authors.lastname: Martin
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Kirkby
authors.forename: James
authors.initials: J
authors.lastname: Alexander
authors.forename: Brett
authors.initials: B
authors.lastname: Daniels
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007858:Learning / Q000187:drug effects; D008140:Lorazepam / Q000097:blood / Q000494:pharmacology*; D008570:Memory, Short-Term / Q000187:drug effects*; D011939:Mental Recall / Q000187:drug effects; D010076:Oxazepam / Q000097:blood / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects; D010465:Perception / Q000187:drug effects*; D011581:Psychological Tests; D011597:Psychomotor Performance / Q000187:drug effects*; D011930:Reaction Time / Q000187:drug effects; D013831:Thiamine / Q000494:pharmacology
chemical_list: D014151:Anti-Anxiety Agents; D010076:Oxazepam; D008140:Lorazepam; D013831:Thiamine