Psychomotor performance under alcohol and under caffeine: Expectancy and pharmacological effects.

Tested the hypothesis that Ss' expectancies about drug effects on psychomotor performance would predict their responses to drug and placebo. 40 male undergraduates were assigned to 1 of 5 treatments: alcohol (0.56 g/kg), placebo alcohol, caffeine (2.93 mg/kg), placebo caffeine, or no treatment. Groups received preliminary training on a pursuit rotor task before rating the effect that caffeine or alcohol was expected to have on their performance. Ss' performance was measured under the treatments and showed impairment under alcohol and improvement under caffeine. However, regardless of whether they received a drug or placebo, those who expected the most impairment performed the most poorly. Results indicate the importance of expectancies in understanding individual differences in response to drugs and placebos. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral tolerance and sensitization to alcohol in humans: The contribution of learning.

This experiment tested the hypothesis that tolerance or sensitization to repeated alcohol doses is predicted by the particular response (diminished or augmented impairment) that is reinforced under drug. Twelve male social drinkers were assigned to a tolerance (T) or sensitization (S) group (n?=?6) and performed a psychomotor task under 0.62 g/kg of alcohol on 5 separate sessions. The 1st session preceded training and determined that the groups' drugged performance did not differ. On 3 subsequent sessions verbal feedback reinforced diminished impairment in Group T and augmented impairment in Group S. During these sessions, Groups T and S displayed tolerance and sensitization, respectively. The final session showed that training effects were retained without reinforcement. The results extend the evidence on the effect of reinforcement to show that it can enhance sensitization as well as tolerance. The findings demonstrate that behavioral variables modulate the response to alcohol and imply that tolerance and sensitization may be affected by a common learning process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol effects on intentional behavior: Dissociating controlled and automatic influences.

This research examined the effect of alcohol on intentional behavior using a process dissociation procedure to separate the influences of conscious controlled processes from those of unconscious automatic processes. In 2 identical experiments, 24 male social drinkers studied a list of words before they received either 0.56 g/kg alcohol, an alcohol placebo, or soda. Participants then performed a word stem completion test that provided estimates of controlled influences and of automatic influences on their responses. The results of the 2 experiments were consistent. Comparisons among the treatments showed that alcohol reduced conscious controlled processes and left automatic processes unchanged. The findings contribute to understanding how the drug may reduce cognitive control of intentional behavior and raise important questions concerning personal and environmental factors that might mediate these effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol, cognitive impairment and expectancies

Right colon diverticulitis, representing 1-3.6% of cases of diverticular disease is an uncommon cause of right lower quadrant pain. Its presentation is difficult to distinguish from acute appendicitis. Patients are between 35 and 50 years old, have a history of 2-3 days of abdominal pain and few gastrointestinal symptoms. The diagnosis is best confirmed by computed tomography and colonoscopy. Conservative treatment is justified in uncomplicated disease, whereas perforations, abcesses and inflammatory tumors require resection. We describe the cases of six patients treated at our institution from 1991 to 1996. Presentation, geographic variations, diagnostic procedures and management are discussed.     

Resistance to cognitive impairment under alcohol: The role of environmental consequences.

This study showed that cognitive impairment under alcohol is affected by environmental factors. Forty male social drinkers were randomly assigned to 4 groups. Participants practiced a task that measured their rate of information processing. Three groups then performed the task under a moderate dose of alcohol (0.62 g/kg) and received either an immediate informative monetary consequence (Ml); a delayed uninformative monetary consequence (M); or no consequence (N) for maintaining their unimpaired processing rate. A control group (C) performed the task without alcohol or any consequence for performance. The processing rates of Groups M and N were slower (i.e. impaired) under alcohol than those of Group C. In contrast, Group MI displayed no significant reduction in processing rate under alcohol (i.e. no impaired). Resistance to the impairing effects of alcohol on information processing is enhanced by a rewarding consequence that conveys information about the adequacy of performance under the drug. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Family history of problem drinking among young male social drinkers: Modeling effects on alcohol consumption.

This research tested the effect of social drinking models on the drinking behavior of 19- to 21-year-old subjects with (FH+) and without (FH-) family histories of problem drinking. The project involved 50 subjects (24 FH+ and 26 FH-) whose drinking habits did not differ. Measures of alcohol intake and the resulting blood alcohol concentration each indicated an interaction between FH and model treatment. The drinking by FH+ subjects changed significantly to conform with the model. Similar but nonsignificant model effects were displayed by FH- subjects. The evidence suggests that social drinking models may have a particularly salient influence on the drinking behavior of FH+ individuals. Because modeling effects have not previously been explored in relation to family history of problem drinking, the present study identifies a promising direction for research on the etiology of alcohol abuse and the development of prevention programs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral effects of alcohol in novice and experienced drinkers: alcohol expectancies and impairment

The possibility was examined that mutational events at the glucose 6-phosphate dehydrogenase locus can be delayed for significantly more than one or two cell divisions following treatment of Chinese hamster cells with UV light. To detect these later mutant events, the proportion of G6PD-mutant cells in a colony was obtained by replating cells from a single colony 5-7 days after UV irradiation and staining the resulting colonies for G6PD activity. Eight colonies out of a total of 1657 colonies from the treated population yielded G6PD-negative colonies upon replating, while no mutant clones were obtained from 947 colonies grown from untreated cells. One clone contained only mutant cells suggesting that the mutation occurred before the first cell division after irradiation. A second clone contained a 1:1 ratio of mutant to wild-type cells suggesting that the mutation occurred at the first cell division. The remaining six clones contained low numbers of mutant cells and the ratio of mutant to wild-type cells in these clones was in agreement with the theoretical ratios expected for mutations occurring at the fourth (1:13), sixth (1:63), seventh (1:127), eighth (1:255), ninth (1:511), and eleventh (1:2047) cell division after UV light exposure. G6PD-mutant cells deficient in staining activity were isolated from five clones and all have significant reductions in G6PD activity confirming the genetically stable character of these mutants. These results support the conclusion that UV light induces mutants for up to 11 cell generations after treatment of mammalian cells and suggest that mutagens can induce in mammalian DNA long-term alterations which act to increase the apparently spontaneous mutation frequency.     

Low blood alcohol discrimination and self-titration skills of social drinkers with widely varied drinking habits.

Six alcohol drinking sessions were administered to 20 males ranging widely in age (18-55 yrs) and classified as "light" or "heavy" social drinkers on the basis of their frequency of drinking and customary dose (ml absolute alcohol/kg). Pretraining measures of accuracy in discriminating low blood alcohol concentrations (BAC) were obtained on Session 1. Training in BAC discrimination (immediate feedback about actual BAC) occurred during Session 2, and Session 3 assessed posttraining effects. Sessions 4-6 tested "self-titration" skill (i.e., self-administration of alcohol to achieve a specific pre-assigned peak BAC). Discrimination of BAC on all posttraining sessions (3-6) was significantly more accurate than pretraining performance. The accuracy with which Ss self-titrated their alcohol to hit a particular peak BAC was consistent over Sessions 4-6 and was comparable to their accuracy in BAC discrimination. The development of these skills had no significant relation to age or drinking habits, suggesting that the training technique may be applicable to a broad spectrum of social drinkers. The importance of feedback in establishing BAC discrimination is discussed, and the consequences of this training, as well as the definition of "light" and "heavy" social drinkers, are identified as important areas for further research. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral effects of combining alcohol and caffeine: Contribution of drug-related expectancies.

This experiment tested the hypothesis that drinkers' expectations about the behavioral effect of combining alcohol and caffeine predicted their psychomotor performance when they expected to receive both drugs. Fifty male social drinkers were assigned to 1 of 4 treatment groups or to a no-treatment control group. Participants in the 4 treatment groups expected and received alcohol (0.56 g/kg). The expectation and the receipt of caffeine (4.4 mg/kg) were manipulated independently. After training on a Pursuit Rotor task, participants rated the expected effect of combining alcohol and caffeine and then received the drug treatments. As predicted, individual differences in expected effects predicted participants' performance when they expected to receive caffeine in combination with alcohol. Regardless of whether caffeine was actually received, those who expected the most impairment from the drug combination performed most poorly. This evidence has implications for understanding factors that contribute to individual differences in behavioral responses to drugs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol-impaired speed and accuracy of cognitive functions: A review of acute tolerance and recovery of cognitive performance.

Much research on the effects of a dose of alcohol has shown that motor skills recover from impairment as blood alcohol concentrations (BACs) decline and that acute tolerance to alcohol impairment can develop during the course of the dose. Comparable alcohol research on cognitive performance is sparse but has increased with the development of computerized cognitive tasks. This article reviews the results of recent research using these tasks to test the development of acute tolerance in cognitive performance and recovery from impairment during declining BACs. Results show that speed and accuracy do not necessarily agree in detecting cognitive impairment, and this mismatch most frequently occurs during declining BACs. Speed of cognitive performance usually recovers from impairment to drug-free levels during declining BACs, whereas alcohol-increased errors fail to diminish. As a consequence, speed of cognitive processing tends to develop acute tolerance, but no such tendency is shown in accuracy. This "acute protracted error" phenomenon has not previously been documented. The findings pose a challenge to the theory of alcohol tolerance on the basis of physiological adaptation and raise new research questions concerning the independence of speed and accuracy of cognitive processes, as well as hemispheric lateralization of alcohol effects. The occurrence of alcohol-induced protracted cognitive errors long after speed returned to normal is identified as a potential threat to the safety of social drinkers that requires urgent investigation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)