Dissociative antagonistic effects of caffeine on alcohol-induced impairment of behavioral control.

The present study examined the separate and combined effects of alcohol and caffeine on behavioral control in a context in which preliminary cues signaled the likelihood that a response should be executed or inhibited. Social drinkers (N = 12) performed a cued go/no-go task that measured control as the quick execution of responses to go targets and sudden suppression of responses to no-go targets. Performance was tested under 3 doses of caffeine (0.0 mg/kg, 2.0 mg/kg, and 4.0 mgl/g) in combination with 2 doses of alcohol (0.0 g/kg and 0.65 g/kg). Alcohol impaired both inhibitory and activational aspects of behavioral control. Caffeine antagonized alcohol effects on response execution but had no effect on inhibitory control. The findings highlight potential differences in how activational and inhibitory aspects of behavioral control respond to drug interactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychostimulant users are sensitive to the stimulant properties of alcohol as indexed by alcohol-induced cardiac reactivity.

One indicator of increased sensitivity to alcohol-induced reward is a heightened heart rate (HR) increase following alcohol intoxication, a characteristic associated with increased alcohol-induced dopamine (DA) release. The goal of this study was to determine whether users of drugs known to induce DA release have higher HR increases after alcohol intoxication than never users have. Sixty-four men with known drug-use histories participated in an alcohol challenge in which HR was measured. Stimulant users had significantly higher ethanol-induced HR increases than never users had, although use of marijuana or hallucinogens was not associated with this marker. Stimulant users obtained superior Sensitivity to Reward scores (R. Torrubia, C. ávila, J. Moltó, & X. Caseras, 2001) compared with never users. Stimulant drug users may be more sensitive to the stimulating properties of alcohol, and this appears to be mediated by superior activity in the Behavioral Approach System (J. A. Gray, 1991). (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)     

Alcohol, Intentional Control, and Inappropriate Behavior: Regulation by Caffeine or an Incentive.

This study shows that reduced intentional control under alcohol can be counteracted by caffeine or an environmental incentive. Four groups of social drinkers (n = 11) received 1 of the following: 0.62 g/kg alcohol (A), alcohol with 4.4 mg/kg caffeine (AC), alcohol with a rewarding monetary incentive (AR), or a placebo (P). They then performed a word stem completion task that provided separate measures of the influence of controlled and automatic processes governing responses. Controlled processes were depressed in Group A compared with Group P, whereas Groups AR and AC did not differ from Group P. Most inappropriate responses were displayed under alcohol alone, fewer with caffeine, and least with incentive. No treatment significantly affected automatic processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol-Induced Impairment of Inhibitory Mechanisms Involved in Visual Search.

The present study examined the effects of alcohol on the ability to perform a cued target detection task that measured inhibition of return (IOR). IOR is a reflexive inhibitory mechanism that delays attention from returning to a previously attended location and has been shown to increase the efficiency of a visual search. Ten social drinkers performed the task under 3 alcohol doses: 0.0 g/kg (placebo), 0.45 g/kg, and 0.65 g/kg. The results showed both active alcohol doses reduced the IOR effect by shortening its duration of influence. The reduced duration of IOR under alcohol suggests that repeated searches in previously explored locations might be more likely under the drug, thereby reducing search efficiency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Clubgoers and their trendy cocktails: Implications of mixing caffeine into alcohol on information processing and subjective reports of intoxication.

Alcoholic drink preferences in college students have made an interesting shift recently, with trends in consumption leaning toward caffeinated alcohol in various forms (e.g., Red Bull and vodka or caffeinated beers such as Anheuser-Busch's B-to-the-E). Despite the dramatic rise in popularity of these beverages, little research has examined the combined effects of alcohol and caffeine, which is problematic for adequately informing the public about the risk or lack thereof of these drinks. The purpose of this study was to directly investigate the acute effects of alcohol and caffeine, alone and in combination, on well-validated measures of cognitive performance and subjective intoxication in social drinkers. Participants (N = 12) performed a psychological refractory period task that measured dual-task interference as the prolonged reaction time to complete the 2nd of 2 tasks performed in close temporal sequence. Performance was tested under 2 active doses and 1 placebo dose of caffeine (0.0 mg/kg, 2.0 mg/kg, and 4.0 mg/kg) in combination with 1 active dose and 1 placebo dose of alcohol (0.0 g/kg and 0.65 g/kg). As expected, alcohol impaired task performance by increasing dual-task interference and increasing errors. The coadministration of caffeine counteracted the effects of alcohol on interference but had no effect on the degree to which alcohol increased errors. Subjective measures of intoxication showed that coadministration of caffeine with alcohol reduced participants' perceptions of alcohol intoxication compared with administration of alcohol alone. The results highlight the complexity of drug interactions between alcohol and caffeine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Salt appetite is enhanced by one prior episode of sodium depletion in the rat.

A single sodium depletion enhances the salt appetite that is expressed after a second and subsequent sodium depletions. The enhanced salt intake, as measured by a decrease in latency to drink and an increase in volume of 3% NaCl ingested, is not accounted for by an increased sodium loss. The enhanced salt intake occurs even when the interval between first and second depletion is as long as 4 months. The enhanced salt appetite does not depend on the drinking of salt after the animal's first sodium depletion and is specific for strong 0.52 M NaCl but not for 0.52 M KCl. Moreover, it can be produced without sodium depletion by the actions of the hormones aldosterone and angiotensin on the brain. These results suggest that angiotensin and aldosterone, which are released in response to sodium depletion, (a) increase renal sodium conservation, (b) evoke a salt appetite to restore the lost sodium, and (c) produce enduring changes in the brain that prepare it for more rapid and more vigorous expression of salt appetite in response to future sodium depletions. Thus the neural mechanisms that govern salt appetite are not only activated by the hormones of sodium conservation but appear also to be organized by them for a lifelong increase in avidity for salty substances. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive impairment influences drinking outcome by altering therapeutic mechanisms of change.

Serious neuropsychological impairments are seen in a minority of addiction treatment clients, and, theoretically, these impairments should undermine behavioral changes targeted by treatment; however, little evidence supports a direct influence of impairment on treatment response. To address this paradox, the authors used structural equation modeling and Project MATCH data (N=1,726) to examine direct, mediated, and moderated paths between cognitive impairment, therapeutic processes, and treatment outcome. Mediated relations were found, wherein impairment led to less treatment compliance, lower self-efficacy, and greater Alcoholics Anonymous Involvement, which, in turn, more proximally predicted drinking. Impairment further moderated the effect of self-efficacy, making it a poor predictor of drinking outcomes in impaired clients, thereby suggesting that impaired and unimpaired clients traverse different pathways to addiction recovery. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acute alcohol tolerance on subjective intoxication and simulated driving performance in binge drinkers.

High rates of binge drinking and alcohol-related problems, including drinking and driving, occur among college students. Underlying reasons for the heightened impaired driving rates in this demographic group are not known. The authors hypothesized that acute tolerance to the interoceptive cues of intoxication may contribute to these maladaptive decisions to drive in binge drinkers. Groups of binge-drinking and non-binge-drinking college students (N = 28) attended sessions during which they received a moderate dose of alcohol (0.65 g/kg) or a placebo. The development of acute tolerance to subjective ratings of intoxication and simulated driving performance was assessed by comparing measures taken during the ascending phase and descending phases of the blood alcohol curve. Compared with placebo, alcohol increased ratings of intoxication and impaired multiple aspects of simulated driving performance in both binge and non-binge drinkers. During the descending phase of the blood alcohol curve, binge drinkers showed acute tolerance to alcohol’s effect on subjective intoxication, and this effect was accompanied by an increased rating of willingness to drive. By contrast, non-binge drinkers showed no acute tolerance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review of Research Advances in Alcohol and Drug Problems.

Reviews the book, Research Advances in Alcohol and Drug Problems edited by Yedy Israel, Frederick B. Glaser, Harold Kalant, Robert E. Popham, Wolfgang Schmidt, and Reginald G. Smart (1981). This book is the sixth volume of the series, Research Advances in Alcohol and Drug Problems. The purpose of this series, as stated by the editors, is not to provide an annual review each year on a fixed selection of topics but rather "to present each year evaluative papers on topics in which enough recent progress has been made to alter the general scope in a particular area." In Volume 6 several chapters deal with highly specialized topics such as: Tolerance to sensitization to central stimulants, brain peptides, liver functions, and mutagenicity of alcohol and tobacco smoke. The prohibitive price $59.50 (U.S. dollars) and highly specialized and diverse nature of many of the chapters in this book, will likely prevent this book from finding its way into many personal libraries. This work would, however, be a worthwhile acquisition for any university or alcohol treatment library. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in caffeine states enhance return of fear in spider phobia.

Treatment of phobias is sometimes followed by a return of fear. Animal and human research has shown that changes in external and internal contexts between the time of treatment and follow-up tests often enhance return of fear. The present study examined whether shifts in caffeine (C) state would enhance return of fear. Participants who were highly afraid of spiders (n=43) were treated in 1-session exposure-based therapy and tested for follow-up 1 week later. Participants were randomly assigned to 1 of 4 groups and received either placebo (P) or C at treatment and follow-up sessions: CC, PP, CP, and PC. Results demonstrated state-dependent learning. Participants experiencing incongruent drug states during treatment and follow-up (CP and PC) exhibited greater return of fear than those experiencing congruent drug states (CC and PP). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic Associations of Alcohol Dehydrogenase With Alcohol Use Disorders and Endophenotypes in White College Students.

Associations of alcohol dehydrogenase (ADH) gene polymorphisms (ADH1B*2 and ADH1C*1) with a lifetime alcohol use disorder (AUD) were examined in White college students. Alcohol-related endophenotypes likely to be influenced by elevations in acetaldehyde were also assessed. Individuals with an ADH1B*2 allele had lower rates of AUDs, consumed a lower maximum number of drinks in a 24-hr period, reported a greater level of response to alcohol, were more likely to have experienced alcohol-induced headaches following 1 or 2 drinks, and reported more severe hangovers than those lacking this allele. These findings are consistent with the hypothesis that enhanced sensitivity to alcohol and lower levels of alcohol use reflect the mechanism by which ADH1B*2 protects against developing an AUD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of alcohol intoxication shows acute tolerance while executive functions remain impaired.

Several psychological constructs (e.g., subjective perception of intoxication, visuomotor speed) display acute tolerance to alcohol, that is, show improvement at declining blood alcohol concentrations (BACs) relative to equivalent rising BACs. However, methodological challenges emerge when attempting to make such comparisons across limbs of the BAC curve, which have proven a barrier to advancing research on acute tolerance. To date, no studies have made multiple comparisons across the entire BAC trajectory. This study employs experimental procedures that overcome some of these difficulties, offering a clearer picture of recovery of impairment for subjective perception of intoxication and cognitive performance and the relationship between them. Twenty participants were assessed at multiple time points over 2 days. Continuous subjective perception of intoxication ratings and cognitive data derived from a computerized measure were paired with a novel analytic paradigm, which allowed comparisons at identified BACs. Results showed acute tolerance for individuals' subjective perception of intoxication and for performance on cognitive tasks measuring visuomotor speed and learning efficiency (recovery from impairment). In contrast, performance on measures of executive function and short-term memory showed no significant difference between limbs at exact concentrations (no recovery from impairment). Therefore, despite participants feeling less intoxicated over time, many cognitive functions remained impaired. The implication for these findings in terms of drunken driving behavior are substantial, suggesting that people may be likely to drive once they subjectively perceive that they have recovered from the acute intoxicating effects of alcohol, despite the persistence of “higher order” cognitive impairments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An index of relative central α-adrenergic receptor antagonism by antipsychotic medications.

Antipsychotic medications exert variable and clinically significant levels of antagonism at central α-adrenergic receptors. To evaluate the impact of this activity on both clinical and experimental measures, an index estimating the relative activity of these medications is needed. We comprehensively searched the empirical literature testing in vitro binding to mammalian brain α-adrenergic receptors of all antipsychotic medications available for clinical use in the United States as of August 2010 and created a quantitative summary index of the potency of binding to α receptors relative to haloperidol (HALα1 and HALα2 equivalents). The potency of binding at α1- and α2-adrenergic receptors varies widely among these medications, with a 532-fold range for α1 antagonism and a 400-fold range for α2 antagonism among atypical antipsychotics. There is considerable overlap between atypical and typical antipsychotic medication groups on each of these measures. This index of HALα equivalents should facilitate the determination of the effects of α-adrenergic antagonism by these medications on clinical efficacy, side effects, and biological and cognitive measures of illness and treatment. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Examining the nature of impairment in visual paired associate learning in amnestic mild cognitive impairment.

Objective: Visual spatial learning is impaired in mild cognitive impairment (MCI) although the nature of this impairment is not clear. This study investigated the nature and magnitude of errors made by adults with amnestic MCI (aMCI) when learning pattern-location paired associations in a continuous manner. Method: Visual associate learning was measured using the Continuous Paired Associate Learning (CPAL) task in which 30 adults who met clinical criteria for aMCI and 30 matched controls were required to learn a set of associations between patterns and locations across increasing memory loads (two, four, six, and eight). Results: As hypothesized, the aMCI group made more total errors than controls for all memory loads above two. However, the rate of increase in errors with memory load in the aMCI group was approximately twice that for controls. Conclusions: In controls, errors on the CPAL task reflected almost exclusively difficulty in memory. In the aMCI group, errors on the CPAL reflected limitations in associative learning but also in short-term memory and response monitoring. These results suggest that impairments in specific aspects of executive function and working memory might contribute to poor performance on visual paired associate learning in aMCI. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Review of Statistics of Alcohol Use and Alcoholism in Canada.

Reviews the book, Statistics of Alcohol Use and Alcoholism in Canada. 1871-1956: First Report by R. E. Popham & W. Schmidt (1970). This volume is the first in what is proposed as an annual census of alcoholism undertaken by the Alcoholism Research Foundation of Ontario. The report includes cataloguing of alcohol statistics by (a) size and characteristics of the drinking population, (b) apparent consumption of alcoholic beverages, (c) convictions for offences involving alcohol, (d) statistics relating to the prevalence of alcoholism and (e) census population estimates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive preoccupation with alcohol and binge drinking in college students: Alcohol-induced priming of the motivation to drink.

This research examined alcohol-induced motivation to drink as a factor that contributes to preoccupation with drinking. Forty undergraduates rated their degree of preoccupation with drinking. The author determined the relationship between the undergraduates' preoccupation and the degree to which alcohol primed their motivation to drink by having them rate their desire for alcohol after they consumed a dose of alcohol or a placebo. Results showed that individual differences in preoccupation were predicted by the priming effects displayed after alcohol was consumed. More preoccupied individuals reported greater priming effects. Priming effects following placebo were minimal and were not related to preoccupation. The research shows that reinforcing effects of alcohol may contribute to cognitive preoccupation with drinking and promote patterns of alcohol abuse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Environmental and pharmacological factors in the development of noncontingent tolerance to cocaine in pigeons.

Previous research with rats and monkeys has shown that tolerance to behavioral effects of cocaine developed if the drug was administered before behavioral test sessions but not if it was administered after sessions, a finding known as contingent tolerance. In contrast, a recent experiment using pigeons found that they showed tolerance resulting from postsession drug administration (noncontingent tolerance). The 4 experiments reported in this article were conducted to examine that result more fully. Experiment 1 found that immediate presession administration of cocaine to pigeons reliably led to tolerance to effects on food-reinforced operant key pecking and that immediate postsession administration of cocaine also led to tolerance in half the subjects, those whose key pecking was not suppressed by postsession dosing. Experiment 2 showed that eating in the home cage under the effects of postsession cocaine was not necessary for tolerance to develop to effects of postsession cocaine and that the majority of subjects developed tolerance from postsession cocaine administration. Experiment 3 found that mere drug exposure in the home cage without exposure to an experimental session did not reliably produce tolerance during the behavioral session. Experiment 4 showed that tolerance from postsession cocaine administration could be observed even when daily dosing was discontinued during dose–response curve assessment. Therefore, the combined results showed that pigeons often developed tolerance to effects of cocaine during the behavioral session when cocaine was administered postsession and that this tolerance was not the result of feeding under effects of the drug. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mapping the Continuum of Alcohol Problems in College Students: A Rasch Model Analysis.

The authors conducted Rasch model (G. Rasch, 1960) analyses of items from the Young Adult Alcohol Problems Screening Test (YAAPST; S. C. Hurlbut & K. J. Sher, 1992) to examine the relative severity and ordering of alcohol problems in 806 college students. Items appeared to measure a single dimension of alcohol problem severity, covering a broad range of the latent continuum. Items fit the Rasch model well, with less severe symptoms reliably preceding more severe symptoms in a potential progression toward increasing levels of problem severity. However, certain items did not index problem severity consistently across demographic subgroups. A shortened, alternative version of the YAAPST is proposed, and a norm table is provided that allows for a linking of total YAAPST scores to expected symptom expression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selectivity of executive function deficits in mild cognitive impairment.

Impairment in executive cognition (EC) is now recognized as relatively common among older persons with mild cognitive impairment (MCI) and may be predictive of the development of dementia. However, both MCI and executive functioning are broad and heterogeneous constructs. The present study sought to determine whether impairments in specific domains of EC are associated with specific subtypes of MCI. MCI patients (n = 124) were divided into 4 subgroups (amnestic vs. nonamnestic, and single- vs. multiple-domain) on the basis of their performance of widely used neuropsychological screening tests. These patients and 68 normal older persons were administered 18 clinical and experimental tests of executive function. Principal components analysis suggested 2 highly reliable EC components, planning/problem solving and working memory, and a less reliable 3rd component, judgment. Planning/problem solving and working memory, but not judgment, were impaired among the MCI patients. This was true even among those with “pure amnestic” MCI, the least impaired group overall. Multiple-domain MCI patients had more severe impairments in planning/problem solving and working memory than single-domain patients, leading to the supposition that they, not pure amnestic MCIs, are at highest risk of imminent dementia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)