Diazepam induces a dissociation between explicit and implicit memory

Until recently, research indicated that all benzodiazepines impair explicit memory, while only lorazepam impairs priming. Stewart and associates provided preliminary data which indicated that both oxazepam and lorazepam may impair implicit memory, but in a time-dependent fashion. The present study was designed to replicate Stewart et al.'s findings after overcoming several limitations of the original study. Thirty subjects were administered an acute dose of lorazepam (2 mg), oxazepam (30 mg) or a placebo and were tested with an implicit (word-stem completion) test and an explicit (cued recall) test. However, subjects were only tested at 170 min post-drug (close to oxazepam's theoretical peak concentration) to rule out the possible "explicit memory contamination" explanation of the Stewart et al. implicit memory findings. Consistent with previous research, both drugs impaired explicit memory relative to placebo. Also, both lorazepam and oxazepam impaired priming performance, supporting the "time-dependence" interpretation of the Stewart et al. findings. The results also indicate that episodic memory is impaired by both benzodiazepines in a time-dependent fashion even when the research methodology used involves everyday memory demands.

Section: Discussionmentioning

confidence: 99%

Section: Tasks and Proceduresmentioning

confidence: 99%

A further examination of the time-dependent effects of oxazepam and lorazepam on implicit and explicit memory

Buffett-Jerrott¹,

Stewart²,

Teehan

1998

“…A range of psychotropic drugs have been shown to leave perceptual implicit memory relatively intact despite their ability to impair explicit memory. These include the anticholinergic, scopolamine (Nissen et al 1987;Kopelman and Corn 1988;Danion et al 1990;Knopman 1991), alcohol (Hashtroudi et al 1984) and benzodiazepines such as diazepam, oxazepam, alprazolam, and triazolam (Fang et al 1987;Danion et al 1989Danion et al , 1990Sellal et al 1992;Weingartner et al 1992;Curran and Gorenstein, 1993;Curran et al 1994;Legrand et al 1995;Vidailhet et al 1996). Only one drug has been found consistently to impair perceptual implicit memory the benzodiazepine lorazepam (Brown et al 1989;Knopman 1991;Danion et al 1992;Sellal et al 1992;Curran and Gorenstein 1993;Vidailhet et al 1994;Bishop and Curran 1995;Bishop et al 1996).…”

Section: Introductionmentioning

confidence: 99%

An investigation of the effects of benzodiazepine receptor ligands and of scopolamine on conceptual priming

Bishop

Curran

1998

Scopolamine and lorazepam both produce anterograde impairments of explicit memory but only lorazepam impairs implicit memory as assessed by perceptual priming tasks. The main aim of the two experiments reported in this article was to determine the effects of these drugs on conceptual priming. Experiment 1 compared the effects of lorazepam (1,2 mg PO) with scopolamine (0.3,0.6 mg SC) and placebo in a study with 60 healthy volunteers. Experiment 2 compared the separate and combined effects of lorazepam (2 mg PO) and flumazenil (2 mg IV) with placebo in a study with 48 healthy volunteers. We found that conceptual priming in category generation tasks was intact following lorazepam in both studies. This preservation of conceptual priming contrasted with lorazepam-induced impairments on explicit memory tasks. In conjunction with previous findings, these results are interpreted as providing further support for the notion that conceptual and perceptual priming are subserved by distinct memory systems, one based on the operations of semantic memory, the other possibly based on a perceptual representation system. That lorazepam impairs perceptual but not conceptual priming suggests that the neurochemical substrates of the two kinds of priming are distinct.

“…Indeed, the fact that lorazepam induces transient amnesia after a single administration is well known Bishop and Curran 1998;Curran et al 1993;Danion 1994;Danion et al 1989Danion et al , 1992File et al 1992;Legrand et al 1995;Pompeia et al 2000;Vidailhet et al 1996;Weingartner et al 1993; for review, see Curran 1991Curran , 1999Curran , 2000BuffetJerrott and Stewart 2002;Vidailhet 2004;Stewart 2005). Experimental results showed that episodic memory is specifically impaired during such amnesic episodes (File et al 1992;Fluck et al 1998;Green et al 1996;Duka et al 1996;Curran 1991Curran , 1999Blin et al 2001) and that this impairment is independent of the benzodiazepine-induced sedative effects (Mintzer and Griffiths 2003;Huron et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Effects of the amnesic drug lorazepam on complete and partial information retrieval and monitoring accuracy

Izaute

Bacon²

2006