Forget "drinking to forget": Enhanced consolidation of emotionally charged memory by alcohol.

Abstract

Social drinkers (42 men, 18-34 years old) participated in a study of the effects of alcohol consumption on incidental memory for emotionally salient verbal stimuli. Participants rated depressing, elating, and neutral statements while sober. Fifteen minutes later they consumed alcohol or active placebo (1.0 or 0.1 ml/kg) in an environment with minimal retrograde interference. In surprise memory testing 24 hr later, when participants were again sober, the alcohol group had increased recall across statement type. The alcohol group also had better recognition of depressing and elating statements, but recognition of neutral statements did not differ between groups. Findings suggest alcohol produced a nonspecific enhancement of incidental memory and that alcohol's motivational properties were not implicated.

Acute Effects of Alcohol on Encoding and Consolidation of Memory for Emotional Stimuli

“…Parker et al (1980Parker et al ( , 1981 first demonstrated this in humans, showing that alcohol improved memory when it was administered immediately following stimulus presentation (i.e., during memory consolidation). Similar findings have since been reported from several different laboratories (Bruce & Pihl, 1997;Bruce et al, 1999a;Knowles & Duka, 2004;Mann et al, 1984). Although the mechanism underlying this post-encoding memory improvement is unknown, several possible explanations have been suggested.…”

“…Bruce et al (1999b) found that alcohol (0.8 g/ kg) increased memory consolidation for elating statements relative to negative statements when tested 24 hours later. However, in two other studies, alcohol (0.8 g/kg) had similar effects on memory consolidation for emotional and neutral stimuli when tested 24 hours later (Bruce & Pihl, 1997;Bruce et al, 1999a). It is possible that these inconsistent findings could be attributable in part to acute alcohol effects (when retrieval is tested on the same day as encoding) or lingering alcohol withdrawal or hangover effects (when retrieval is tested 24 hours after encoding).…”

“…The between-groups design and group sizes are in line with previous studies of acute alcohol effects on memory encoding and consolidation (Bruce & Pihl, 1997;Bruce et al, 1999b;Knowles & Duka, 2004). Subjects were randomly assigned to the conditions, and at the first session they viewed standardized visual images with positive, negative, or neutral content.…”

Ethanol Enhances Reactivated Fear Memories

“…There also are several reports, which showed that ethanol has effects when administered during post-training. In humans, ethanol administered after training actually facilitates learning ability for many tasks (Parker et al, 1980;Lamberty et al, 1990;Tyson and Schirmuly, 1994;Bruce and Pihl, 1997;Hewitt et al, 1996). However, conflicting results are reported in animal studies.…”

“…Since then, several studies reported the effect on humans. They revealed that post-training administration of ethanol improved verbal recall (Parker et al, 1980;Lamberty et al, 1990;Tyson and Schirmuly, 1994), visual recognition (Parker et al, 1981), verbal recognition (Bruce and Pihl, 1997), and kinesthetic memory (Hewitt et al, 1996). In animals, post-training ethanol treatment improves performance in a water-finding task in rats (Melia et al, 1986) and social memory in rats (Prediger and Takahashi, 2003).…”