¹Utrecht Institute for Pharmaceutical Sciences, Department of Psychopharmacology, University of Utrecht, Utrecht, The Netherlands

Correspondence: JC Verster, Utrecht Institute for Pharmaceutical Sciences, Department of Psychopharmacology, PO Box 80082, 3508 TB Utrecht, The Netherlands. Tel: +31 30 253 69 09; Fax: +31 30 253 73 87; E-mail: J.C.Verster@pharm.uu.nl

Received 30 May 2002; Revised 30 September 2002; Accepted 2 October 2002.

Abstract

The impairing effects on memory functioning after acute alcohol intoxication in healthy volunteers and after chronic use in alcoholics are well established. However, research determining the next-morning effects of a single episode of binge drinking on memory functioning is scarce. A total of 48 healthy volunteers participated in a single-blind study comprising an evening (baseline) session, followed by a treatment administration (ethanol 1.4 g/kg or placebo), and a morning session. Memory was tested with a word-learning test (including immediate and delayed recall, and recognition). Further, a 45-min Mackworth clock test for measuring vigilance was included (parameters: number of hits and false alarms) and subjective alertness was assessed, to infer whether word-learning test findings reflect sedation or specific memory impairments. Delayed recall in the morning session was significantly worse in the alcohol group when compared to the placebo group (F_1,42=6.0, p<0.02). In contrast, immediate recall and recognition were unimpaired in the alcohol group. In the morning session, relative to the placebo group, subjective alertness was significantly reduced in the alcohol group before and after the tests (F_1,44=8.7, p<0.005; F_1,44=13.3, p<0.001, respectively). However, in the Mackworth clock test, the alcohol group and placebo group did not differ significantly in the morning session. The specific findings of impaired delayed recall show that memory retrieval processes are significantly impaired during alcohol hangover. Vigilance performance was not significantly affected, indicating that this memory impairment does not reflect sedation.