The effects of tolerance on state-dependent learning in social drinkers

Next day effects of naturalistic alcohol consumption on tasks of attention

OBJECTIVES

The aim of this study was to examine the next day effects of alcohol consumption on a range of attention tasks.

METHODS

The study followed a counterbalanced repeated measure design, with participants tested the morning following normal/usual alcohol consumption and again the morning after no alcohol consumption. Participants were 48 social drinkers (15 men and 33 women), who performed attention tests at 9 am, 11 am, or 1 pm. Performance was assessed by tasks measuring sustained attention, divided attention, selective attention, and spatial attention and by the Stroop test.

RESULTS

The morning after alcohol consumption, a significantly higher proportion of missed targets was observed (F(1, 40) = 6.43, p < 0.05) in the sustained attention task. In the Stroop test, participants responded significantly slower (F(1, 42) = 8.72, p < 0.005) in the interference condition (when naming the color of the ink of the words) the morning after alcohol consumption. In the selective attention task, the consumption of alcohol the night before eliminated the robust distance by compatibility interaction, which was observed the morning after no alcohol consumption (F(1, 43) = 10.41, p < 0.01). No influence of alcohol was observed in the divided attention test nor in the spatial attention task.

CONCLUSION

Alcohol consumption has a negative impact on some but not all facets of attentional processing the morning after a normal nights drinking.

Next day effects of a normal night's drinking on memory and psychomotor performance

AIM

To investigate in social drinkers the effects of a 'normal' evening of drinking alcohol on cognitive performance.

METHODS

Aiming for ecological validity, the study required participants to consume their usual quantity of any type of alcoholic beverage in their chosen company (hangover situation). However, the timing of drinking was restricted to the period between 22:00 and 02:00 hours on the night before testing. Testing included memory and psychomotor performance tests; testing was also performed after an evening of abstinence (no hangover situation), following a counterbalanced design using repeated measures, with time of testing (09:00, 11:00 and 13:00 hours) and order of testing (hangover/no hangover; no hangover/hangover) as 'between participant' factors in the analysis.

RESULTS

Forty-eight social drinkers (33 women, 15 men) aged between 18 and 43 years were tested, with a 1-week interval between test sessions. The morning after alcohol (mean consumption: 14.7 units for men; 10.4 units for women), free recall was impaired at 09:00 hours and delayed recognition and psychomotor performance were impaired throughout the morning, despite blood alcohol levels of zero or very near zero.

CONCLUSION

Memory and psychomotor performance is impaired on the morning after heavy 'social' drinking.

Does alcohol affect memory for emotional and non-emotional experiences in different ways?

Alcohol has been shown to have both impairing and facilitating effects on memory, depending on the sequencing of learning and ingestion of the drug. Its effects on memory for emotional material, however, have not been shown reliably. The current experiment sought to investigate the effects of alcohol on later recall of emotional and neutral events experienced before and after alcohol drinking. Using an incidental-learning paradigm, alcohol (0.65 g/kg) or placebo was administered in a double-blind randomized design to 34 participants, between two learning phases in which they viewed and rated positive, negative and neutral images. The drug's effects on memory were assessed in a surprise test of free recall. In addition, impact of alcohol on ratings of mood states, and of valence and arousal that the pictures evoked, was examined. Alcohol facilitated memory for material seen before, and impaired memory for material seen after, its administration. Furthermore, under alcohol, emotional images in the first set were more recalled over neutral than in the second set, indicating a higher retrograde facilitation for emotional than for neutral material. Alcohol improved positive mood states but had no effect on negative mood states. Evaluation of pictures with regard to valence showed an increase of the ratings for the positive and neutral images after alcohol and a decrease after placebo. No drug effects were found for arousal ratings. Whether a picture was likely to be remembered or not (tested only for set 2) was dependent on the intensity of the arousal but not of the valence that the picture evoked in the participants. Pictures that were rated high in arousal were also remembered better, and this effect was irrespective of alcohol or placebo ingestion. These data have shown that alcohol elicits retrograde facilitation and anterograde impairment for emotional materials. Furthermore, these data demonstrate that alcohol selectively facilitates memories for emotional events experienced before administration, and suggest a possible explanation for the reinforcing effects of drinking.

Peer attitudes, sex, and the effects of alcohol on simulated driving performance

This study presents an investigation of the effects of peer attitude, gender, and blood alcohol level on driving performance using a driving simulator. The subjects were 18 male and 18 female social drinkers from the general population, aged 18-25, and holding a current drivers' licence. Subjects were randomly assigned to pro or against drinking driving conditions and tested at different blood alcohol levels. The results revealed that subjects in the for drinking driving condition perceived themselves to be more capable than they actually were and drove increasingly faster and made more mistakes than subjects in the against drinking driving condition when under the influence of alcohol. Significant sex differences were observed only for performance on the driving simulator. Males, in the main, engaged in more dangerous driving and risk taking in simulated driving conditions than females.