A comparison of the sedative and amnestic effects of chlorpromazine and lorazepam

Abstract

The effects of single doses of chlorpromazine (100 mg) and lorazepam (0.5, 1 and 2 mg) were compared with placebo in a battery of tests of information processing, working and semantic memory. Peak saccadic velocity was used to provide a precise and reliable measure of sedation and its results were found to be consistent with those using visual analogue rating scales. Chlorpromazine 100 mg was equally sedative to lorazepam 2 mg. Lorazepam caused dose-dependent deterioration in performance in many of the memory tests, whereas an equally sedative dose of chlorpromazine did not. These data therefore support the view that benzodiazepine-induced amnesia is not secondary to sedation. Peak saccadic velocity has considerable advantages over visual analogue scales as a measure of sedation, since it is objective and has a demonstrated low coefficient of variation. It is suggested that saccadic eye movement measurement will permit considerably more reliable and precise separation of the sedative and amnestic effects of drugs and will allow investigation of amnesia caused by clinically relevant doses of psychotropic drugs.

Psychomotor slowing and planning deficits in schizophrenia

“…In schizophrenia, antipsychotic medication can directly alter cognitive processing; it may, for instance, bring about an improvement of the disturbed (selective) attention (see . It can also cause sedation, like in healthy subjects, because of the anticholinergic activity of antipsychotics (Green, McElholm & King, 1996). Sedation, however, was not measured in the present study, so we cannot rule out that the sedative component of the antipsychotic treatment contributed to the psychomotor slowing observed in our patient group.…”

Specific Effects of an Amnesic Drug: Effect of Lorazepam on Study Time Allocation and on Judgment of Learning

“…Indeed, the fact that the lorazepam drug induces a transient amnesia following a single intake has been repeatedly shown Bishop and Curran, 1998;Curran et al, 1993;Danion, 1994;Danion et al, 1989Danion et al, , 1992File et al, 1992;Legrand et al, 1995;Pompéia et al, 1996;Vidailhet et al, 1996;Weingartner et al, 1993). During the amnesic episode, results have shown that episodic memory is specifically impaired (File et al, 1992;Fluck et al, 1998;Green et al, 1996;Duka et al, 1996;Curran 1991Curran , 1999Blin et al, 2001) and that it is independent of the benzodiazepine-induced sedative effects (Mintzer and Griffiths, 2003a;Huron et al, 2002). Interestingly, participants do not seem to be aware of their memory deficits (Curran et al, 1987).…”

Effects of benzodiazepines on explicit memory in a paediatric surgery setting

“…Performance-based objective sedation measures should also be used, as participants who appear sedated to an observer may not actually show decreased performance on an objective sedation (e.g. psychomotor speed) task (Green et al 1996;Buffett-Jerrott and Stewart 2002). Several laboratory-based studies with adults have found that benzodiazepines also significantly impair attention (e.g.…”