Differential effects of alcohol on working memory: distinguishing multiple processes

Alcohol consumption's effects on working memory: Examining familial confounding

OBJECTIVE

The purpose of our study was to provide a more rigorous test of the causal hypothesis that chronic alcohol use impairs working memory performance.

METHOD

We measured linear associations between a latent factor representing alcohol consumption and accuracy across four working memory tasks before and after accounting for familial confounding using a cotwin control design. Specifically, this study examined accuracy through a latent working memory score, the National Institutes of Health (NIH) Toolbox List Sorting, NIH Toolbox Picture Sequence, Penn Word Memory, and 2-back tasks. The study included data from 158 dizygotic and 278 monozygotic twins (Mage = 29 ± 3 years).

RESULTS

In our initial sample-wide analysis, we did not detect any statistically significant associations between alcohol use and working memory accuracy. However, our cotwin control analyses showed that twins with greater levels of alcohol use exhibited worse scores on the latent working memory composite measure (B = -.25, CI [-.43, -.08], p < .01), Picture Sequence (B = -.31, CI [-.55, -.08], p < .01), and List Sorting (B = -.28, CI [-.51, -.06 ], p = .01) tasks than did their cotwins.

CONCLUSIONS

These results are consistent with a potentially causal relationship between alcohol use and working memory performance that can be detected only after accounting for confounding familial factors. This highlights the importance of understanding the mechanisms that may underlie negative associations between alcohol use and cognitive performance, as well as the potential factors that influence both alcohol behaviors and cognition. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The Relation Between Attention and Memory

The relation between attention and memory has long been deemed important for understanding cognition, and it was heavily researched even in the first experimental psychology laboratory by Wilhelm Wundt and his colleagues. Since then, the importance of the relation between attention and memory has been explored in myriad subdisciplines of psychology, and we incorporate a wide range of these diverse fields. Here, we examine some of the practical consequences of this relation and summarize work with various methodologies relating attention to memory in the fields of working memory, long-term memory, individual differences, life-span development, typical brain function, and neuropsychological conditions. We point out strengths and unanswered questions for our own embedded processes view of information processing, which is used to organize a large body of evidence. Last, we briefly consider the relation of the evidence to a range of other theoretical views before drawing conclusions about the state of the field.

The Effect of Alcohol and Sexual Arousal on Explicit and Implicit Condom Attitudes and Intentions to Use a Condom

Alcohol and sexual arousal are contextual determinants of condomless sex. Dual-process theory postulates that two types of cognitive processing contribute to the regulation of behavior: one that is fast, intuitive and automatic, and another that is slower and deliberative. This study applied a dual-process model to investigate condomless sexual behavior, highlighting the potential importance of implicit attitudes in condomless sex. We investigated whether the impact of alcohol and sexual arousal on condom use-related attitudes and intentions was explained by diminished working memory capacity, as dual-process models suggest. We also investigated whether this effect could be explained by implicit and explicit attitudes toward condom use. Male participants (N = 30) were randomized using a 2 × 2 within-subjects design that manipulated alcohol intoxication (placebo vs. alcohol beverages) and sexual arousal (neutral vs. erotic movie clips). We measured participants' working memory capacity, intentions to use a condom, and explicit and implicit attitudes toward condom use. Significant main effects of alcohol intoxication and sexual arousal on working memory capacity were found. No significant interaction was found for the combined effect of alcohol intoxication and sexual arousal on intentions to use a condom. There was no significant effect of implicit attitudes on intentions to use a condom, although a trend toward significance (p = 0.06) was found for the effect of implicit attitudes on intentions to use a condom when participants were in a state of alcohol intoxication. Theoretical and practical implications of this study are discussed.

A social contextual review of the effects of alcohol on emotion

Drinking and drinking problems are complex phenomena. Understanding the etiology of alcohol use disorder requires consideration of biological, psychological, and social processes. It is our view that the last of these dimensions is just beginning to receive adequate scrutiny. In this selective review, we discuss the concept of a biopsychosocial analysis of the effects of alcohol. After briefly addressing biological and psychological research on alcohol's emotional effects, we bid to make a case for the vital role that social processes play in understanding why people drink. The bulk of the paper describes research illustrating the contributions that a social psychological perspective can make to advance understanding of the rewarding effects of alcohol. Overall, studies incorporating social contexts have revealed reliable evidence that alcohol enhances emotional experience in many social environments and have identified socio-contextual variables that moderate responses to alcohol. Further, these studies have broadened the scope of constructs thought to be socially rewarding, including social bonding, relationship functioning, and humor enjoyment. Our analysis concludes by identifying research areas we believe would profit from additional research.

Effects of alcohol on sleep and nocturnal heart rate: Relationships to intoxication and morning-after effects

BACKGROUND

Alcohol consumption produces feelings of well-being and stimulation, but also impairs psychomotor performance, disturbs cardiovascular function and sleep, and can disrupt next-day mood and behavior. A deeper understanding of how the acute effects of alcohol relate to its sleep and morning-after effects is needed to minimize harm resulting from its use. This study examined relationships between the effects of a high dose of alcohol on subjective and psychomotor measures, nocturnal heart rate, sleep quality, and morning-after mood and behavior. We hypothesized that alcohol would produce disturbances in cardiovascular and sleep regulation during the night, which would predict morning-after mood and behavioral performance.

METHODS

Thirty-one men and women participated in two overnight laboratory visits during which they consumed either alcohol (1.0 g/kg for men, 0.85 g/kg for women) or placebo (randomized, crossover design). They consumed the beverage from 8 to 9 pm, and remained in the laboratory overnight for polysomnographic sleep recording. Subjective and behavioral measures were obtained during consumption and at 7-8 am the morning after.

RESULTS

Alcohol increased both negative and positive arousal, urge to drink and sedation, and it impaired performance on behavioral tasks. During sleep, alcohol produced expected tachycardia and detriments in sleep quality including decreased total sleep time, sleep efficiency, and altered sleep architecture. Only modest effects on mood or performance were detected the following morning. The acute sedative-like effects of alcohol were related to increases in N2 sleep, but not to other disruptions in sleep or nocturnal heart rate, and neither sleep impairments nor nocturnal heart rate were related to mood or task performance the morning after.

CONCLUSIONS

The effects of alcohol on sleep and nocturnal heart rate were not strongly related to either its acute or morning-after effects. These findings do not provide strong support for the idea that alcohol-induced sleep disruptions underlie morning-after effects.

Effects of acute alcohol administration on working memory: a systematic review and meta-analysis

RATIONALE

Alcohol-induced executive function deficits may underlie associations between alcohol, self-regulation, and hazardous behaviors. Studies examining the effects of alcohol administration on working memory, an important executive functioning component, have produced mixed findings. Acute alcohol effects on working memory remain unclear.

OBJECTIVES

We aimed to conduct a systematic review and meta-analysis on the effects of acute alcohol administration on working memory outcomes in studies of healthy adults.

METHODS

We performed a systematic search of PubMed, MEDLINE, and PsycINFO from inception to June 2021. Studies were included if they met criteria, including healthy participants and administration of quantified alcohol doses against comparative controls. Data extracted included primary working memory outcomes, alcohol doses, and study characteristics. Study quality was assessed using an established validity measure. Working memory task type, alcohol dose, control condition type, and sex/gender composition were explored as moderators using mixed-effects models and meta-regressions.

RESULTS

Thirty-two studies (1629 participants) provided sufficient data for 54 comparisons between alcohol and control conditions. Random-effects meta-analysis indicated that alcohol administration produced significant, small- to medium-sized working memory decrements (g [95% CI] =  - 0.300 [- 0.390 to - 0.211], p < 0.001). Moderation analyses suggested that these effects differed as a function of task type, dose, control condition type, and sex/gender composition. The average quality rating across studies was good.

CONCLUSIONS

Alcohol administration significantly impaired working memory performance, particularly when executive-related manipulation processes were involved. Future research is needed to investigate how alcohol-induced working memory impairments relate to compromised self-regulation, hazardous behavior, and negative drinking consequences.

Understanding ethanol's acute effects on medial prefrontal cortex neural activity using state-space approaches

Acute ethanol (EtOH) intoxication results in several maladaptive behaviors that may be attributable, in part, to the effects of EtOH on neural activity in medial prefrontal cortex (mPFC). The acute effects of EtOH on mPFC function have been largely described as inhibitory. However, translating these observations on function into a mechanism capable of delineating acute EtOH's effects on behavior has proven difficult. This review highlights the role of acute EtOH on electrophysiological measurements of mPFC function and proposes that interpreting these changes through the lens of dynamical systems theory is critical to understand the mechanisms that mediate the effects of EtOH intoxication on behavior. Specifically, the present review posits that the effects of EtOH on mPFC N-methyl-d-aspartate (NMDA) receptors are critical for the expression of impaired behavior following EtOH consumption. This hypothesis is based on the observation that recurrent activity in cortical networks is supported by NMDA receptors, and, when disrupted, may lead to impairments in cognitive function. To evaluate this hypothesis, we discuss the representation of mPFC neural activity in low-dimensional, dynamic state spaces. This approach has proven useful for identifying the underlying computations necessary for the production of behavior. Ultimately, we hypothesize that EtOH-related alterations to NMDA receptor function produces alterations that can be effectively conceptualized as impairments in attractor dynamics and provides insight into how acute EtOH disrupts forms of cognition that rely on mPFC function. This article is part of the special Issue on 'Neurocircuitry Modulating Drug and Alcohol Abuse'.

Reduced Working Memory is Associated with Heavier Alcohol Consumption History, Role Impairment and Executive Function Difficulties

Both HIV status and heavy alcohol use have been associated with reduced cognitive function, particularly in the domains of working memory and executive function. It is unclear what aspects of working memory and executive function are associated with HIV status and heavy alcohol use and whether performance on these measures are associated with functional impairment. We examined the relationship between HIV, history of heavy alcohol consumption, and HIV/alcohol interaction on speeded tests of frontal inhibitory abilities, a working memory task related to mental manipulation of letters and numbers, cognitive flexibility, and measures of functional impairment. Study participants included 284 individuals (151 HIV +) recruited from two different studies focusing on HIV associated brain dysfunction, one specific to the effects of alcohol, the other specific to the effects of aging. HIV status was not independently associated with working memory and executive function measures. Higher level of alcohol consumption was associated with reduced performance on Letter Number Sequencing. Poorer Letter Number Sequencing performance was associated with role impairment (an inability to do certain kinds of work, housework, or schoolwork) and executive function difficulties. Future studies should examine causal associations and interventions targeting working memory abilities.

Influence of Alcohol and Cognitive Capacity on Visual Number Judgements

We used an enumeration task to address the question of whether acute alcohol intoxication reduces cognitive or perceptual capacity. To control for individual differences in cognitive resources, we took a sober record of each participant's working memory capacity (WMC). Alcohol was expected to impair enumeration performance, either for the automatic parallel counting of small stimulus sets indicating a perceptual impairment, or the controlled counting or estimating of larger sets indicating a cognitive impairment. Enumeration showed an overall decline in accuracy following a vodka beverage and the deficit was negligible for small sets, which is inconsistent with a loss of perceptual capacity. Having a higher WMC facilitated the enumeration of larger sets and the correlation between WMC and accuracy was stronger in the alcohol condition suggesting that low-WMC participants were more impaired by the beverage. Our findings therefore suggest that alcohol diminished cognitive rather than perceptual capacity.

Acute alcohol intoxication and the cocktail party problem: do "mocktails" help or hinder?

RATIONALE

To test the notion that alcohol impairs auditory attentional control by reducing the listener's cognitive capacity.

OBJECTIVES

We examined the effect of alcohol consumption and working memory span on dichotic speech shadowing and the cocktail party effect-the ability to focus on one of many simultaneous speakers yet still detect mention of one's name amidst the background speech. Alcohol was expected either to increase name detection, by weakening the inhibition of irrelevant speech, or reduce name detection, by restricting auditory attention on to the primary input channel. Low-span participants were expected to show larger drug impairments than high-span counterparts.

METHODS

On completion of the working memory span task, participants (n = 81) were randomly assigned to an alcohol or placebo beverage treatment. After alcohol absorption, they shadowed speech presented to one ear while ignoring the synchronised speech of a different speaker presented to the other. Each participant's first name was covertly embedded in to-be-ignored speech.

RESULTS

The "cocktail party effect" was not affected by alcohol or working memory span, though low-span participants made more shadowing errors and recalled fewer words from the primary channel than high-span counterparts. Bayes factors support a null effect of alcohol on the cocktail party phenomenon, on shadowing errors and on memory for either shadowed or ignored speech.

CONCLUSION

Findings suggest that an alcoholic beverage producing a moderate level of intoxication (M BAC ≈ 0.08%) neither enhances nor impairs the cocktail party effect.

Suicide Attempts: How Does the Acute Use of Alcohol Affect Suicide Intent?

BACKGROUND

Very few studies have specifically addressed the role of the acute use of alcohol (AUA) in suicide attempts.

OBJECTIVE

Our study compared the suicide intent scores of self-poisoning patients with and without AUA in order to examine the role of alcohol in attempted suicides.

METHODS

We recruited 516 patients admitted to the emergency department for self-poisoning. We screened blood alcohol concentrations (BACs) to determine whether these were positive or negative in the two groups. We collected data about covariates such as psychiatric disorders and sociodemographic and suicide characteristics. We then compared suicide intent between the groups, adjusted according to the covariates.

RESULTS

The patients with AUA had lower scores for suicide intent, but this factor only reduced the self-reporting score, with the scores for objective circumstances and risk similar between the groups. There was a correlation between BACs and self-reported suicide intentionality, but this was not significant.

CONCLUSION

Acute use of alcohol patients presented with lower suicide intent, as particularly explained by the self-report scores, but there were no differences between the groups in terms of risk and/or the objective circumstances. The role of alcohol in the self-reporting of suicide attempts must be addressed in future studies.

Gaze entropy measures detect alcohol-induced driver impairment

Driving under the influence of alcohol is an ongoing cause of road traffic accidents. The biphasic nature of alcohol effects on subjective experience appears to contribute to the prevalence of drink-driving, as people perceive the declining phase of the BAC curve as recovery from intoxication and are more willing to drive despite significant impairments in objectively measured functions. The present study investigates whether alcohol-induced changes in gaze behaviour can be detected during engagement in a simulated driving task. In a repeated-measures and placebo-controlled design, this study examines the biphasic influence of moderate alcohol intake (0.6 g/kg) on measures of gaze behaviour and simulated driving performance. Twenty-two healthy young adults completed three driving sessions (baseline, ascending and descending) under two conditions (placebo, alcohol) while their eye movements were simultaneously recorded. The results revealed that gaze behaviour as measured by gaze transition entropy (GTE) and stationary gaze entropy (SGE) and driving performance measured by the standard deviation of lateral position (SDLP) of the vehicle, were significantly affected by alcohol across the ascending and descending sessions. The alcohol-induced reduction in GTE with an increase in SGE is discussed as alcohol's impact on top-down modulation of gaze resulting in more dispersed and erratic pattern of visual scanning. The observed changes in gaze behaviour also mediated the influence of alcohol upon driving performance. These results have significant implications for the development of driver monitoring systems that can detect alcohol-induced impairment.

Acute alcohol and cognition: Remembering what it causes us to forget

Addiction has been conceptualized as a specific form of memory that appropriates typically adaptive neural mechanisms of learning to produce the progressive spiral of drug-seeking and drug-taking behavior, perpetuating the path to addiction through aberrant processes of drug-related learning and memory. From that perspective, to understand the development of alcohol use disorders, it is critical to identify how a single exposure to alcohol enters into or alters the processes of learning and memory, so that involvement of and changes in neuroplasticity processes responsible for learning and memory can be identified early. This review characterizes the effects produced by acute alcohol intoxication as a function of brain region and memory neurocircuitry. In general, exposure to ethanol doses that produce intoxicating effects causes consistent impairments in learning and memory processes mediated by specific brain circuitry, whereas lower doses either have no effect or produce a facilitation of memory under certain task conditions. Therefore, acute ethanol does not produce a global impairment of learning and memory, and can actually facilitate particular types of memory, perhaps particular types of memory that facilitate the development of excessive alcohol use. In addition, the effects on cognition are dependent on brain region, task demands, dose received, pharmacokinetics, and tolerance. Additionally, we explore the underlying alterations in neurophysiology produced by acute alcohol exposure that help to explain these changes in cognition and highlight future directions for research. Through understanding the impact that acute alcohol intoxication has on cognition, the preliminary changes potentially causing a problematic addiction memory can better be identified.

Drunk decisions: Alcohol shifts choice from habitual towards goal-directed control in adolescent intermediate-risk drinkers

BACKGROUND

Studies in humans and animals suggest a shift from goal-directed to habitual decision-making in addiction. We therefore tested whether acute alcohol administration reduces goal-directed and promotes habitual decision-making, and whether these effects are moderated by self-reported drinking problems.

METHODS

Fifty-three socially drinking males completed the two-step task in a randomised crossover design while receiving an intravenous infusion of ethanol (blood alcohol level=80 mg%), or placebo. To minimise potential bias by long-standing heavy drinking and subsequent neuropsychological impairment, we tested 18- to 19-year-old adolescents.

RESULTS

Alcohol administration consistently reduced habitual, model-free decisions, while its effects on goal-directed, model-based behaviour varied as a function of drinking problems measured with the Alcohol Use Disorders Identification Test. While adolescents with low risk for drinking problems (scoring <8) exhibited an alcohol-induced numerical reduction in goal-directed choices, intermediate-risk drinkers showed a shift away from habitual towards goal-directed decision-making, such that alcohol possibly even improved their performance.

CONCLUSIONS

We assume that alcohol disrupted basic cognitive functions underlying habitual and goal-directed decisions in low-risk drinkers, thereby enhancing hasty choices. Further, we speculate that intermediate-risk drinkers benefited from alcohol as a negative reinforcer that reduced unpleasant emotional states, possibly displaying a novel risk factor for drinking in adolescence.

Exercise as adjunctive treatment for alcohol use disorder: A randomized controlled trial

Aims

To examine whether physical activity as an adjunct to outpatient alcohol treatment has an effect on alcohol consumption following participation in an exercise intervention of six months’ duration, and at 12 months after treatment initiation.

Methods

The study is a randomized controlled study with three arms: Patients allocated to (A) treatment as usual, (B) treatment as usual and supervised group exercise, (C) treatment as usual and individual physical exercise. The primary outcome measure was excessive drinking six months after treatment start and completion of the intervention. A logistic regression model was used to evaluate the odds of excessive drinking among the three groups, based on intention-to-treat. Changes in level of physical activity in all three groups were tested by using a generalized linear mixed model. A multiple linear model was used to test if there was an association between amount of performed physical activity and alcohol consumption.

Results

A total of 175 patients (68.6% male) participated. Response rates were 77.7% at six months and 57.1% at 12 months follow-up. OR 0.99 [95% CI: 0.46; 2.14], p = 0.976 for excessive drinking in the group exercise condition, and 1.02 [95% CI: 0.47; 2.18], p = 0.968 in the individual exercise condition, which, when compared to the control group as reference, did not differ statistically significantly. Participants with moderate level physical activity had lower odds for excessive drinking OR = 0.12 [0.05; 0.31], p<0.001 than participants with low level physical activity. Amount of alcohol consumption in the intervention groups decreased by 4% [95% CI: 0.03; 6.8], p = 0.015 for each increased exercising day.

Conclusions

No direct effect of physical exercise on drinking outcome was found. Moderate level physical activity was protective against excessive drinking following treatment. A dose-response effect of exercise on drinking outcome supports the need for implementing physically active lifestyles for patients in treatment for alcohol use disorder.

Blood Alcohol Concentration-Related Lower Performance in Immediate Visual Memory and Working Memory in Adolescent Binge Drinkers

The binge drinking (BD) pattern of alcohol consumption is prevalent during adolescence, a period characterized by critical changes to the structural and functional development of brain areas related with memory and cognition. There is considerable evidence of the cognitive dysfunctions caused by the neurotoxic effects of BD in the not-yet-adult brain. Thus, the aim of the present study was to evaluate the effects of different blood alcohol concentrations (BAC) on memory during late adolescence (18–19 years old) in males and females with a history of BD. The sample consisted of 154 adolescents (67 males and 87 females) that were classified as refrainers if they had never previously drunk alcoholic drinks and as binge drinkers if they had drunk six or more standard drink units in a row for men or five or more for women at a minimum frequency of three occasions in a month, throughout the previous 12 months. After intake of a high acute dose of alcohol by binge drinkers or a control refreshment by refrainers and binge drinkers, subjects were distributed into four groups for each gender according to their BAC: BAC0-R (0 g/L, in refrainers), BAC0-BD (0 g/L, in binge drinkers), BAC1 (0.3 – 0.5 g/L, in binge drinkers) or BAC2 (0.54 – 1.1 g/L, in binge drinkers). The subjects’ immediate visual memory and working memory were then measured according to the Wechsler Memory Scale (WMS-III). The BAC1 group showed lower scores of immediate visual memory but not of working memory, while lower performance in both memories were found in the BAC2 group. Therefore, the brain of binge drinkers with moderate BAC could be employing compensatory mechanisms from additional brain areas to perform a working memory task adequately, but these resources would be undermined when BAC is higher (>0.5 g/L). No gender differences were found in BAC-related lower performance in immediate visual memory and working memory. In conclusion, immediate visual memory is more sensitive than working memory to the neurotoxic effects of alcohol in adolescent binge drinkers of both genders, being a BAC-related lower performance, and without obvious differences between males and females.

Impairment of Neuroplasticity in the Dorsolateral Prefrontal Cortex by Alcohol

Previous studies have demonstrated that alcohol consumption impairs neuroplasticity in the motor cortex. However, it is unknown whether alcohol produces a similar impairment of neuroplasticity in the dorsolateral prefrontal cortex (DLPFC), a brain region that plays an important role in cognitive functioning. The aim of the current study was to evaluate the effect of alcohol intoxication on neuroplasticity in the DLPFC. Paired associative stimulation (PAS) combined with electroencephalography (EEG) was used for the induction and measurement of associative LTP-like neuroplasticity in the DLPFC. Fifteen healthy subjects were administered PAS to the DLPFC following consumption of an alcohol (1.5 g/l of body water) or placebo beverage in a within-subject cross-over design. PAS induced neuroplasticity was indexed up to 60 minutes following PAS. Additionally, the effect of alcohol on PAS-induced potentiation of theta-gamma coupling (an index associated with learning and memory) was examined prior to and following PAS. Alcohol consumption resulted in a significant impairment of mean (t = 2.456, df = 13, p = 0.029) and maximum potentiation (t = −2.945, df = 13, p = 0.011) compared to the placebo beverage in the DLPFC and globally. Alcohol also suppressed the potentiation of theta-gamma coupling by PAS. Findings from the present study provide a potential neurophysiological mechanism for impairment of cognitive functioning by alcohol.

Effects of acute alcohol intoxication on executive functions controlling self-regulated behavior

Alcohol consumption may lead to deficits in the executive functions that govern self-regulation. These deficits could lead to risk-taking behaviors; therefore, it is important to determine the magnitude of these deficits on executive functioning. The purpose of this experiment was to investigate the acute effects of alcohol on three of the executive functions that are hypothesized to affect self-regulation, which are inhibition, set shifting, and working memory, using a mixed-methods study design. The participants were 75 moderate or heavy drinkers between the ages of 21 and 35 who were randomized into one of three beverage conditions (control, placebo, or 0.65-g alcohol dose/kg body weight). Performance on working memory, set shifting, and inhibition were measured pre- and post-beverage consumption. The results showed only a significant interaction in the working memory data, as there was an increase in performance post-beverage relative to pre-beverage for the control participants as compared to the alcohol and placebo participants. It was concluded that the dose of alcohol (BAC = 0.063%) given to moderate to heavy drinkers was not sufficient to cause significant impairment in the executive functions tested. The results were further discussed and methodological concerns were considered, such as the low BAC achieved, practice effects, and insensitivity of tasks.

The effects of alcohol on emotion in social drinkers

Understanding why people drink alcohol and in some cases develop drinking problems has long puzzled researchers, clinicians, and patients alike. In the mid-1940s and early 1950s, experimental research began to systematically investigate alcohol's hedonic properties. Presumably, alcohol consumption would prove reinforcing as a consequence of its capacity either to relieve stress or to brighten positive emotional experiences. This article reviews experimental research through the years examining the impact of alcohol on both the relief of negative affect and the enhancement of positive affect. It covers initial accounts that emphasized direct pharmacological effects of ethanol on the central nervous system. These early studies offered surprisingly tepid support for the premise that alcohol improved emotional states. Next, studies conducted in the 1970s are considered. Informed by social learning theory and employing advances derived from experimental psychology, this research sought to better understand the complex effects of alcohol on emotion. Coverage of this work is followed by discussion of current formulations, which integrate biological and behavioral approaches with the study of cognitive, affective, and social processes. These current perspectives provide insight into the particular conditions under which alcohol can boost emotional experiences. Finally, future research directions and clinical implications are considered.

Ecological momentary assessment of working memory under conditions of simultaneous marijuana and tobacco use

BACKGROUND AND AIMS

The neuropsychological correlates of simultaneous marijuana and tobacco use are largely unknown, which is surprising as both substances have similar neural substrates and have opposing influences on working memory (WM). This study examined the effects of marijuana alone, tobacco alone and simultaneous marijuana and tobacco use on WM.

DESIGN

Primary aims were tested using a within-subject design, controlling for multiple subject- and momentary-level confounds via ecological momentary assessment (EMA).

SETTING

Data collection occurred in the Chicago, USA area in participants' natural environments.

PARTICIPANTS

Participants were 287 community young adults from a larger natural history study, oversampled for ever smoking, all of whom event-recorded at least one substance use occasion during the study week.

MEASUREMENTS

Momentary tobacco, marijuana and alcohol use were recorded during multiple EMA across 1 week of data capture. WM was assessed at the end of each EMA assessment. Contextual variables that may influence WM were recorded via EMA.

FINDINGS

There were main effects for marijuana and tobacco: WM was poorer with marijuana [odds ratio (OR) = 0.91, 95% confidence interval (CI) = 0.84-0.99] and better with tobacco (OR = 1.11, 95% CI = 1.04-1.18). These effects were not qualified by an interaction (OR = 1.03, 95% CI = 0.84-1.26). Alcohol also reduced WM (OR = 0.87, 95% CI = 0.79-0.95), and the tobacco × alcohol interaction was significant (OR = 0.81, 95% CI = 0.66-0.99), indicating that the facilitative effect of tobacco disappeared with concurrent alcohol use.

CONCLUSIONS

Relative to when individuals did not use these substances, working memory decreased with acute marijuana and alcohol use and increased with acute tobacco use. However, the putative effect of marijuana on working memory and the facilitative effect of tobacco on working memory were no longer present when used simultaneously with tobacco and alcohol, respectively. Data suggest that tobacco use may compensate for working memory decrements from marijuana among young adults and highlight the importance of investigating further the negative impact of alcohol use on cognition.

The Synergistic Impact of Excessive Alcohol Drinking and Cigarette Smoking upon Prospective Memory

The independent use of excessive amounts of alcohol or persistent cigarette smoking have been found to have a deleterious impact upon Prospective Memory (PM: remembering future intentions and activities), although to date, the effect of their concurrent use upon PM is yet to be explored. The present study investigated the impact of the concurrent use of drinking excessive amounts of alcohol and smoking cigarettes (a "Polydrug" group) in comparison to the combined effect of the single use of these substances upon PM. The study adopted a single factorial independent groups design. The Cambridge Prospective Memory Test (CAMPROMPT) is a test of both time-based and event-based PM and was used here to measure PM. The CAMPROMPT was administered to 125 adults; an excessive alcohol user group (n = 40), a group of smokers who drink very little alcohol (n = 20), a combined user group (the "Polydrug" group) who drink excessively and smoke cigarettes (n = 40) and a non-drinker/low alcohol consumption control group (n = 25). The main findings revealed that the Polydrug users recalled significantly fewer time-based PM tasks than both excessive alcohol users p < 0.001 and smokers p = 0.013. Polydrug users (mean = 11.47) also remembered significantly fewer event-based PM tasks than excessive alcohol users p < 0.001 and smokers p = 0.013. With regards to the main aim of the study, the polydrug users exhibited significantly greater impaired time-based PM than the combined effect of single excessive alcohol users and cigarette smokers p = 0.033. However, no difference was observed between polydrug users and the combined effect of single excessive alcohol users and cigarette smokers in event-based PM p = 0.757. These results provide evidence that concurrent (polydrug) use of these two substances has a synergistic effect in terms of deficits upon time-based PM. The observation that combined excessive drinking and cigarette smoking leads to a greater impairment in time-based PM may be of paramount importance, given the key role PM plays in everyday independent living.

Effects of alcohol intake on time-based event expectations

Previous evidence suggests that alcohol affects various forms of temporal cognition. However, there are presently no studies investigating whether and how alcohol affects on time-based event expectations. Here, we investigated the effects of alcohol on time-based event expectations. Seventeen healthy volunteers, aged between 19 and 36 years, participated. We employed a variable foreperiod paradigm with temporally predictable events, mimicking a computer game. Error rate and reaction time were analyzed in placebo (0 g/kg), low dose (0.2 g/kg) and high dose (0.6 g/kg) conditions. We found that alcohol intake did not eliminate, but substantially reduced, the formation of time-based expectancy. This effect was stronger for high doses, than for low doses, of alcohol. As a result of our studies, we have evidence that alcohol intake impairs time-based event expectations. The mechanism by which the level of alcohol impairs time-based event expectations needs to be clarified by future research.

Effect of Alcohol and Tobacco Smoke on Long-Term Memory and Cell Proliferation in the Hippocampus of Rats

INTRODUCTION

Alcohol is frequently used in combination with tobacco and few studies explore interactions between these two drugs of abuse. Here, we evaluated the effect of chronic alcohol administration and concomitant exposure to tobacco smoke on long-term memory and on cell proliferation in the hippocampus of rats.

METHODS

Forty male Wistar rats were assigned to four groups and treated with alcohol (2g/kg by gavage) and/or exposed to tobacco smoke (from six cigarettes, by inhalation) twice a day (at 9:00 AM and 2:00 PM) for 30 days. Long-term memory was evaluated in the inhibitory avoidance test and hippocampal cell proliferation was analyzed for bromodeoxyuridine immunohistochemistry.

RESULTS

Our results showed that alcohol, tobacco smoke, or their combination improved the long-term memory evaluated by the memory index in rats. Moreover, alcohol and tobacco coadministration decreased bromodeoxyuridine-labeled cells by 60% when compared to the control group, while alcohol treatment decreased labeled cells by 40%. The tobacco group showed a nonsignificant 26% decrease in labeled cells compared to the control group.

CONCLUSIONS

Chronic alcohol and tobacco coadministration improves the long-term memory in rats in the inhibitory avoidance test. However, coadministration decreases the cell proliferation in the hippocampus of rats, suggesting a deleterious effect by the combined use of these drugs of abuse.

Cannabinoid Ligands and Alcohol Addiction: A Promising Therapeutic Tool or a Humbug?

The vast therapeutic potential of cannabinoids of both synthetic and plant-derived origins currently makes these compounds the focus of a growing interest. Although cannabinoids are still illicit drugs, their possible clinical usefulness, including treatment of acute or neuropathic pain, have been suggested by several studies. In addition, some observations indicate that cannabinoid receptor antagonists may be useful for the treatment of alcohol dependence and addiction, which is a major health concern worldwide. While the synergism between alcohol and cannabinoid agonists (in various forms) creates undesirable side effects when the two are consumed together, the administration of CB1 antagonists leads to a significant reduction in alcohol consumption. Furthermore, cannabinoid antagonists also mitigate alcohol withdrawal symptoms. Herein, we present an overview of studies focusing on the effects of cannabinoid ligands (agonists and antagonists) during acute or chronic consumption of ethanol.

Pharmacodynamic interactions of a solid formulation of sodium oxybate and ethanol in healthy volunteers

AIM

The pharmacologic effects of sodium oxybate (SO) have a number of similarities with those of alcohol. This study evaluated the pharmacodynamic interaction of SMO.IR (a solid immediate release formulation of SO) and alcohol (0.7 (males) or 0.57 (females) g kg(-1) alcohol using 40% vodka).

METHODS

In a randomized, double-blind, double-dummy, crossover trial, 24 healthy volunteers received randomly a) 2.25 g SMO.IR and placebo alcohol preparation, b) 2.25 g f SMO.IR and alcohol, c) 2.25 g SMO.IR matching placebo and alcohol and d) 2.25 g of SMO.IR matching placebo and placebo alcohol preparation. Objective and subjective cognitive parameters, adverse events and vital signs were assessed before, 15 and 165 min after treatment administration.

RESULTS

Alcohol produced the expected cognitive impairment and the expected subjective sedation rapidly after intake (from 15 min). The objective effects of SMO.IR were much less pronounced than those of alcohol. The reverse was observed for subjective complaints, which were related to lesser stimulation and greater sedation. Nevertheless, 165 min after administration this sedation feeling was less with SMO.IR than with alcohol. There was a significant interaction between SMO.IR and alcohol at 15 min (i.e. increase in alertness and stimulation and decrease in sedation). In addition, an isolated mild decrease in digit vigilance accuracy occurred at 165 min post-dose after the combination. The co-administration of SMO.IR and alcohol was safe and well-tolerated.

CONCLUSION

SMO.IR and alcohol have distinct adverse effect profiles. The objective effects of SMO.IR are much less marked than those of alcohol. No deleterious interaction was observed.

Systematic review of neurocognition in people with co-occurring alcohol misuse and depression

BACKGROUND

Alcohol misuse and depression represent two major social and health problems globally. These conditions commonly co-occur and both are associated with significant cognitive impairment. Despite this, few studies have examined the impact on cognitive functioning of co-occurring alcohol misuse and depression. This study aims to critically review findings from peer-reviewed published articles examining neuropsychological test performance among samples of people with co-occurring alcohol misuse and depression.

METHOD

A comprehensive literature search was conducted, yielding six studies reporting neuropsychological profiles of people with co-occurring alcohol misuse and depression. Results comparing cognitive functioning of people with this comorbidity to those with alcohol misuse alone, depression alone, healthy controls and published norms were examined as well as those describing the correlation between depressive symptoms and cognitive functioning in people with alcohol use disorders.

RESULTS

In the majority of instances, the comorbid groups did not differ significantly from those with depression only or alcohol misuse only, nor from healthy controls or published norms. In the cases where a difference in neuropsychological test scores between groups was found, it was not consistently identified across studies. However, visual memory was identified in two studies as being impaired in comorbid samples and is worthy of inclusion in future studies.

LIMITATIONS

Due to the small number of included studies and the large variation in inclusion criteria as well as differing assessment tools and methodologies between studies, the review did not include a quantitative synthesis.

CONCLUSIONS

Research into cognitive deficits among people with singly occurring versus co-occurring alcohol misuse and depression is accumulating. Evidence suggests that the neuropsychological performance among samples with this comorbidity is generally not severely impaired and is unlikely to preclude benefit from treatment.

Give me just a little more time: effects of alcohol on the failure and recovery of cognitive control

Numerous externalizing behaviors, from aggression to risk taking to drug abuse, stem from impaired cognitive control, including that brought about by the acute effects of alcohol. Although research generally indicates that alcohol impairs cognitive abilities, a close examination of the literature suggests that alcohol's effects are quite variable and likely depend on a number of contextual factors. The purpose of the current study was to characterize the effects of alcohol on cognitive control in terms of neural and behavioral responses to successful and unsuccessful control attempts. Participants were randomly assigned to consume an alcohol (0.80 g/kg ETOH), placebo, or nonalcoholic control beverage prior to completing a cognitive control (flanker) task while event-related brain potentials were recorded. Alcohol reduced the amplitude of the error-related negativity on error trials and increased the posterror compatibility effect in response time. Of particular interest, neural indices of conflict monitoring and performance adjustment (frontal slow wave) were attenuated by alcohol, but only on trials following errors. These functions had recovered, however, by 2 trials after an error. These findings suggest that alcohol's effects on cognitive control are best characterized as impaired (or delayed) recovery following control failures. Implications of these findings for understanding alcohol's effects on behavioral undercontrol are discussed.

Alcohol use across the lifespan: An analysis of adolescent and aged rodents and humans

Adolescence and old age are unique periods of the lifespan characterized by differential sensitivity to the effects of alcohol. Adolescents and the elderly appear to be more vulnerable to many of alcohol's physiological and behavioral effects compared to adults. The current review explores the differential effects of acute alcohol, predominantly in terms of motor function and cognition, in adolescent and aged humans and rodents. Adolescents are less sensitive to the sedative-hypnotic, anxiolytic, and motor-impairing effects of acute alcohol, but research results are less consistent as it relates to alcohol's effects on cognition. Specifically, previous research has shown adolescents to be more, less, and similarly sensitive to alcohol-induced cognitive deficits compared to adults. These equivocal findings suggest that learning acquisition may be differentially affected by ethanol compared to memory, or that ethanol-induced cognitive deficits are task-dependent. Older rodents appear to be particularly vulnerable to the motor- and cognitive-impairing effects of acute alcohol relative to younger adults. Given that alcohol consumption and abuse is prevalent throughout the lifespan, it is important to recognize age-related differences in response to acute and long-term alcohol. Unfortunately, diagnostic measures and treatment options for alcohol dependence are rarely dedicated to adolescent and aging populations. As discussed, although much scientific advancement has been made regarding the differential effects of alcohol between adolescents and adults, research with the aged is underrepresented. Future researchers should be aware that adolescents and the aged are uniquely affected by alcohol and should continue to investigate alcohol's effects at different stages of maturation.

Executive Functioning in Alcohol Use Studies: A Brief Review of Findings and Challenges in Assessment

There is a wealth of research about the links between executive functioning (EF) and alcohol use. However, difficulty may arise in interpreting findings because of the variability between studies regarding the specific components of EF measured, as well as the variability of tasks used to examine each EF construct. The current article considers each of these problems within the context of a literature review that focuses on two topics: (1) the efficacy of EF in predicting alcohol use and alcohol-related consequences, and (2) the effect of acute alcohol intoxication on EF task performance. An additional goal was to identify and describe commonly used EF measures with the intention of providing alcohol researchers information on the assessment of different EF domains. Our findings indicate that there is strong evidence supporting a relation between EF difficulties (particularly response inhibition and information updating) and alcohol use, with additional evidence of a significant interaction between EF and implicit associations on alcohol use. In contrast, research supporting a link between set shifting abilities and later alcohol use is scarce. Additionally, this review found evidence of alcohol acutely affecting many EF processes (particularly response inhibition). Overall, there is a need to replicate these findings with commonly used EF tasks (versus developing numerous tasks within individual laboratories) to better advance our understanding of the relation between EF and alcohol use.

Attention to advertising and memory for brands under alcohol intoxication

In an attempt to discover new possibilities for advertising in uncluttered environments marketers have recently begun using ambient advertising in, for instance, bars and pubs. However, advertising in such licensed premises have to deal with the fact that many consumers are under the influence of alcohol while viewing the ad. This paper examines the effect of alcohol intoxication on attention to and memory for advertisements in two experiments. Study 1 used a forced exposure manipulation and revealed increased attention to logos under alcohol intoxication consistent with the psychopharmacological prediction that alcohol intoxication narrows attention to the more salient features in the visual environment. Study 2 used a voluntary exposure manipulation in which ads were embedded in a magazine. The experiment revealed that alcohol intoxication reduces voluntary attention to ads and leads to a significant reduction in memory for the viewed ads. In popular terms consuming one or two beers reduces brand recall from 40 to 36% while being heavily intoxicated further reduces brand recall to 17%.

Alcohol disrupts the effects of priming on the perception of ambiguous figures

Inhibitory mechanisms are thought to underpin the well-documented impairing effects of alcohol on attention. Here, we use a novel priming paradigm to investigate the effects of alcohol on inhibitory mechanisms in attention. Participants were assigned to an alcohol (N=15), or placebo (N=15) group. The dose of alcohol was 0.8 g/kg for males and 0.75 g/kg for females. Participants were asked to report figure reversals during presentation of the face-vase ambiguous figure. Prior to this, they were shown a prime that was either semantically relevant to the face-vase stimulus or was neutral. Semantic priming decreased the number of figure reversals in the first half of the test session in the placebo group but not in the alcohol group. The placebo group was also more likely than the alcohol group to report the first interpretation of the figure to be the same as the semantic prime. Prior presentation of a semantic prime had a stabilising effect on reversal rate, suggesting that the primed interpretation inhibited the alternate interpretation. The absence of an effect in the alcohol group is consistent with an alcohol-related impairment of this inhibition.

Dose-related effects of alcohol on cognitive functioning

We assessed the suitability of six applied tests of cognitive functioning to provide a single marker for dose-related alcohol intoxication. Numerous studies have demonstrated that alcohol has a deleterious effect on specific areas of cognitive processing but few have compared the effects of alcohol across a wide range of different cognitive processes. Adult participants (N = 56, 32 males, 24 females aged 18–45 years) were randomized to control or alcohol treatments within a mixed design experiment involving multiple-dosages at approximately one hour intervals (attained mean blood alcohol concentrations (BACs) of 0.00, 0.048, 0.082 and 0.10%), employing a battery of six psychometric tests; the Useful Field of View test (UFOV; processing speed together with directed attention); the Self-Ordered Pointing Task (SOPT; working memory); Inspection Time (IT; speed of processing independent from motor responding); the Traveling Salesperson Problem (TSP; strategic optimization); the Sustained Attention to Response Task (SART; vigilance, response inhibition and psychomotor function); and the Trail-Making Test (TMT; cognitive flexibility and psychomotor function). Results demonstrated that impairment is not uniform across different domains of cognitive processing and that both the size of the alcohol effect and the magnitude of effect change across different dose levels are quantitatively different for different cognitive processes. Only IT met the criteria for a marker for wide-spread application: reliable dose-related decline in a basic process as a function of rising BAC level and easy to use non-invasive task properties.

Differential effects of alcohol on contrast processing mediated by the magnocellular and parvocellular pathways

This study investigated how acute alcohol intake affects contrast processing mediated by inferred magnocellular (MC) and parvocellular (PC) pathways. Achromatic contrast discrimination thresholds were measured in 16 young healthy participants using a steady-pedestal, pulsed-pedestal or pedestal-Δ-pedestal paradigm designed to favor the inferred MC or the PC pathway. Each participant completed two randomized sessions that included consumption of either 0.8 g/kg alcohol or a placebo beverage, with each session consisting of contrast discrimination measurements at baseline and at 60 min following beverage consumption. The results showed that, compared to placebo, alcohol significantly reduced MC contrast sensitivity and PC contrast gain but had no effect on PC contrast sensitivity for the majority of the participants; and did not alter MC contrast gain consistently across participants. The decrease in contrast gain in the PC pathway can be interpreted as a degradation of the postretinal signal-to-noise ratio, whereas the decrease of sensitivity in the MC pathway likely results from a change of cortical processing.

Effects of alcohol on sequential information processing: evidence for temporal myopia

Alcohol Myopia Theory (AMT) posits that alcohol restricts the focus of attention, such that behaviors are determined only by highly salient environmental cues. While AMT is most commonly understood in terms of spatial attention, the present study tested the effects of alcohol in the temporal domain of attention. Seventy-one participants consumed either a placebo beverage or one of two doses of alcohol (0.40g/kg or 0.80g/kg ETOH) before performing an auditory discrimination task while event-related potentials (ERPs) were recorded. Consistent with typical sequential effects, placebo participants showed increased P300 amplitude and slowed behavioral responses when the current target differed from the two-back tone. In contrast, alcohol caused increased P300 and response slowing when the target tone differed from the one-back tone. These findings suggest that alcohol increases the salience of more recently encountered information, consistent with the general tenets of AMT.

A diffusion model decomposition of the effects of alcohol on perceptual decision making

RATIONALE

Even in elementary cognitive tasks, alcohol consumption results in both cognitive and motor impairments (e.g., Schweizer and Vogel-Sprott, Exp Clin Psychopharmacol 16: 240-250, 2008).

OBJECTIVES

The purpose of this study is to quantify the latent psychological processes that underlie the alcohol-induced decrement in observed performance.

METHODS

In a double-blind experiment, we administered three different amounts of alcohol to participants on different days: a placebo dose (0 g/l), a moderate dose (0.5 g/l), and a high dose (1 g/l). Following this, participants performed a "moving dots" perceptual discrimination task. We analyzed the data using the drift diffusion model. Model parameters drift rate, boundary separation, and non-decision time allow a decomposition of the alcohol effect in terms of their respective cognitive components, that is, rate of information processing, response caution, and non-decision processes (e.g., stimulus encoding, motor processes).

RESULTS

We found that alcohol intoxication causes higher mean RTs and lower response accuracies. The diffusion model decomposition showed that alcohol intoxication caused a decrease in drift rate and an increase in non-decision time.

CONCLUSIONS

In a simple perceptual discrimination task, even a moderate dose of alcohol decreased the rate of information processing and negatively affected the non-decision component. However, alcohol consumption left response caution largely intact.

Alcohol effects on performance monitoring and adjustment: affect modulation and impairment of evaluative cognitive control

Alcohol is known to impair self-regulatory control of behavior, though mechanisms for this effect remain unclear. Here, we tested the hypothesis that alcohol's reduction of negative affect (NA) is a key mechanism for such impairment. This hypothesis was tested by measuring the amplitude of the error-related negativity (ERN), a component of the event-related brain potential (ERP) posited to reflect the extent to which behavioral control failures are experienced as distressing, while participants completed a laboratory task requiring self-regulatory control. Alcohol reduced both the ERN and error positivity (Pe) components of the ERP following errors and impaired typical posterror behavioral adjustment. Structural equation modeling indicated that effects of alcohol on both the ERN and posterror adjustment were significantly mediated by reductions in NA. Effects of alcohol on Pe amplitude were unrelated to posterror adjustment, however. These findings indicate a role for affect modulation in understanding alcohol's effects on self-regulatory impairment and more generally support theories linking the ERN with a distress-related response to control failures.