The effects of heavy social drinking on executive function: a systematic review and meta-analytic study of existing literature and new empirical findings

Alcohol use disorder as a moderator of the relationship between posttraumatic stress disorder and suicidality among military personnel

BACKGROUND

Alcohol use disorder (AUD), posttraumatic stress disorder (PTSD), and suicide are substantial public health concerns among military service members, yet the nature of their relationships is not well understood. Here, we tested the hypothesis that AUD moderates the relationship between PTSD symptom severity and suicidal ideation.

METHODS

This secondary analysis uses data collected at baseline for a randomized clinical trial. The sample consists of 160 active-duty service members from three service branches (Army, Air Force, and Navy). All participants met diagnostic criteria for PTSD and were not engaged in evidence-based PTSD treatment at the time of enrollment. Zero-inflated Poisson generalized linear regression models were used to test the associations of PTSD and AUD symptom severity with the presence and severity of suicidal ideation.

RESULTS

Findings suggest that AUD symptom severity moderates (i.e., amplifies) the relationship between PTSD symptoms and severity of suicidal ideation among military personnel with untreated PTSD. Among service members with mild or absent AUD, we found no significant association between PTSD symptoms and the severity of suicidal ideation. However, when AUD severity was average (i.e., sample mean) or high (mean + 1SD), PTSD symptoms were significantly positively associated with the severity of suicidal ideation.

CONCLUSIONS

This study highlights the importance of assessing AUD and PTSD as a part of suicide risk evaluations of veterans. The results also provide strong support for the maintenance and further development in the military health system of treatment programs that simultaneously address AUD and PTSD comorbidity.

Sex-difference in the association between social drinking, structural brain aging and cognitive function in older individuals free of cognitive impairment

Background

We investigated a potential sex difference in the relationship between alcohol consumption, brain age gap and cognitive function in older adults without cognitive impairment from the population-based Mayo Clinic Study of Aging.

Methods

Self-reported alcohol consumption was collected using the food-frequency questionnaire. A battery of cognitive testing assessed performance in four different domains: attention, memory, language, and visuospatial. Brain magnetic resonance imaging (MRI) was conducted using 3-T scanners (Signa; GE Healthcare). Brain age was estimated using the Brain-Age Regression Analysis and Computational Utility Software (BARACUS). We calculated the brain age gap as the difference between predicted brain age and chronological age.

Results

The sample consisted of 269 participants [55% men (n=148) and 45% women (n=121) with a mean age of 79.2 ± 4.6 and 79.5 ± 4.7 years respectively]. Women had significantly better performance compared to men in memory, (1.12 ± 0.87 vs 0.57 ± 0.89, P<0.0001) language (0.66 ± 0.8 vs 0.33 ± 0.72, P=0.0006) and attention (0.79 ± 0.87 vs 0.39 ± 0.83, P=0.0002) z-scores. Men scored higher in visuospatial skills (0.71 ± 0.91 vs 0.44 ± 0.90, P=0.016). Compared to participants who reported zero alcohol drinking (n=121), those who reported alcohol consumption over the year prior to study enrollment (n=148) scored significantly higher in all four cognitive domains [memory: F3,268 = 5.257, P=0.002, Language: F3,258 = 12.047, P<0.001, Attention: F3,260 = 22.036, P<0.001, and Visuospatial: F3,261 = 9.326, P<0.001] after correcting for age and years of education. In addition, we found a significant positive correlation between alcohol consumption and the brain age gap (P=0.03). Post hoc regression analysis for each sex with language z-score revealed a significant negative correlation between brain age gap and language z-scores in women only (P=0.008).

Conclusion

Among older adults who report alcohol drinking, there is a positive association between higher average daily alcohol consumption and accelerated brain aging despite the fact that drinkers had better cognitive performance compared to zero drinkers. In women only, accelerated brain aging is associated with worse performance in language cognitive domain. Older adult women seem to be vulnerable to the negative effects of alcohol on brain structure and on certain cognitive functions.

The Influence of Alcohol Consumption on Gambling: Do the Laboratory Study Findings Generalize to Natural Environments?

A recent meta-analysis of laboratory studies on the effects of acute alcohol consumption on risk-taking did not support that acute alcohol consumption increased risk-taking. Questions about whether this finding generalizes to those gambling in naturalistic settings remain. Therefore, we examined the gambling behavior of frequent gamblers who did and did not consume alcohol while gambling. Participants were 769 weekly gamblers (66% male) who were U.S. residents and at least 18 years old. Participants recruited via MTurk completed measures through the Qualtrics survey platform. Significant predictors of gambling under the influence of alcohol were drinking days per month and PGSI score. A linear regression model predicting percentage of time spent gambling under the influence of alcohol revealed that gambling days per week, gambling hours per day, PGSI score, and drinking days per month were significant predictors. Finally, significant predictors of spending at least 50% of gambling time gambling under the influence of alcohol included: gambling hours per day, PGSI score, and drinking days per month. These findings were consistent with the recent meta-analysis of laboratory studies. However, finding that gambling disorder symptoms and overall rates of alcohol consumption were related to gambling under the influence of alcohol replicated the frequently found relation of alcohol problems among those who also exhibit gambling problems.

Neurobiological mechanisms of control in alcohol use disorder - moving towards mechanism-based non-invasive brain stimulation treatments

Alcohol use disorder (AUD) is characterized by excessive habitual drinking and loss of control over alcohol intake despite negative consequences. Both of these aspects foster uncontrolled drinking and high relapse rates in AUD patients. Yet, common interventions mostly focus on the phenomenological level, and prioritize the reduction of craving and withdrawal symptoms. Our review provides a mechanistic understanding of AUD and suggests alternative therapeutic approaches targeting the mechanisms underlying dysfunctional alcohol-related behaviours. Specifically, we explain how repeated drinking fosters the development of rigid drinking habits and is associated with diminished cognitive control. These behavioural and cognitive effects are then functionally related to the neurobiochemical effects of alcohol abuse. We further explain how alterations in fronto-striatal network activity may constitute the neurobiological correlates of these alcohol-related dysfunctions. Finally, we discuss limitations in current pharmacological AUD therapies and suggest non-invasive brain stimulation (like TMS and tDCS interventions) as a potential addition/alternative for modulating the activation of both cortical and subcortical areas to help re-establish the functional balance between controlled and automatic behaviour.

Subjective executive function deficits in hazardous alcohol drinkers

BACKGROUND

Dependent alcohol drinkers exhibit differences in the structure and function of the brain, and impairments in cognitive function, including executive functions (EFs). Less is known about the impact of non-dependent but hazardous use (that which raises the risk of harm), and it is also unclear to what extent executive impairments in this cohort affect real-world function. The current study examines the relationship between alcohol use, EF and alcohol-related problems, in the general population.

METHODS

A between-groups cross-sectional design assessed EF across two levels of drinking; hazardous (Alcohol Use Disorders Identification Test (AUDIT) score of ⩾8) and non-hazardous. Alcohol drinkers (n = 666; 136 male; 524 female; six not disclosed; aged 28.02 ± 10.40 years) completed validated questionnaires online assessing subjective EF, alcohol use and alcohol-related problems.

RESULTS

Organisation, Strategic Planning, Impulse Control and overall function were significantly impaired in hazardous drinkers. Furthermore, the effect of alcohol on EF, partially mediated the relationship between alcohol use and alcohol-related problems.

CONCLUSION

Hazardous drinking was associated with lower subjective EF, and this mediated the effect of alcohol on alcohol-related problems. This may be due to changes in prefrontal brain regions, which could indicate greater risk for the development of alcohol dependence (AD). Future research should use additional means to assess EF in hazardous drinkers, including recovery of function, development of AD and the relationship between cognition and alcohol-related daily problems.

Alcohol intoxication, but not hangover, differentially impairs learning and automatization of complex motor response sequences

Behavioral automatization usually makes us more efficient and less error-prone, but may also foster dysfunctional behavior like alcohol abuse. Yet, it has remained unclear whether alcohol itself causes the shift from controlled to habitual behavior commonly observed in alcohol use disorder (AUD). We thus investigated how the acute and post-acute effects of binge drinking affect the automatization of motor response sequences and the execution of automated vs. controlled motor response sequences. N = 70 healthy young men performed a newly developed automatization paradigm once sober and once after binge drinking (half of them intoxicated and half of them hungover). While we found no significant effects of alcohol hangover, acute intoxication (~ 1.2 ‰) had two dissociable effects: Firstly, it impaired the automatization of complex motor response sequence execution. Secondly, it eliminated learning effects in response selection and pre-motor planning processes. The results suggest that alcohol hangover did not affect controlled or automated processes, and disprove the assumption that alcohol intoxication generally spares or facilitates motor response sequence automatization. As these effects could be specific to the investigated explicit learning context, acute intoxication might potentially still improve the execution of pre-existing automatisms and/or the implicit acquisition of motor response sequence automatisms.

Effect of Distance to Trauma Centre, Trauma Centre Level, and Trauma Centre Region on Fatal Injuries among Motorcyclists in Taiwan

Background: Studies have suggested that trauma centre-related risk factors, such as distance to the nearest trauma hospital, are strong predictors of fatal injuries among motorists. Few studies have used a national dataset to study the effect of trauma centre-related risk factors on fatal injuries among motorists and motorcyclists in a country where traffic is dominated by motorcycles. This study investigated the effect of distance from the nearest trauma hospital on fatal injuries from two-vehicle crashes in Taiwan from 2017 to 2019. Methods: A crash dataset and hospital location dataset were combined. The crash dataset was extracted from the National Taiwan Traffic Crash Dataset from 1 January 2017 through 31 December 2019. The primary exposure in this study was distance to the nearest trauma hospital. This study performed a multiple logistic regression to calculate the adjusted odds ratios (AORs) for fatal injuries. Results: The multivariate logistic regression models indicated that motorcyclists involved in crashes located ≥5 km from the nearest trauma hospital and in Eastern Taiwan were approximately five times more likely to sustain fatal injuries (AOR = 5.26; 95% CI: 3.69–7.49). Conclusions: Distance to, level of, and region of the nearest trauma centre are critical risk factors for fatal injuries among motorcyclists but not motorists. To reduce the mortality rate of trauma cases among motorcyclists, interventions should focus on improving access to trauma hospitals.

Automatic aspects of response selection remain unchanged during high-dose alcohol intoxication

Regular binge-drinking increases the risk of developing alcohol use disorder (AUD) and induces similar acute effects on behavioral control, particularly in case of response selection conflicts. No such effects have been reported for automatic/bottom-up response selection, even though AUD alters automaticity. However, it has never been reliably tested whether this domain is truly unchanged during high-dose alcohol intoxication. To investigate this question with the help of Bayesian analyses, we subjected n=31 young healthy male participants to a within-subject design, where each participant was tested twice in a counter-balanced order (ie, once sober and once intoxicated at 1.1‰). On each appointment, the participants performed the S-R paradigm, which assesses automatic stimulus-response (S-R) binding within the framework of the theory of event coding (TEC). In short, the TEC states that stimulus features and responses become encoded in an event file when they occur simultaneously. These event files will be reactivated by any matching stimulus feature, thus facilitating the encoded response (and hampering different responses). Alcohol led to a general decrease in behavioral performance, as demonstrated by significant main effects of intoxication status on accuracy and response times (all P ≤ .009). We also reproduced typical task effects, but did not find any significant interactions with the intoxication factor (all P ≥ .099). The latter was further substantiated by Bayesian analyses providing positive to strong evidence for the null hypothesis. Taken together, our results demonstrate that even high-dose alcohol intoxication does not impair automatic response selection/S-R associations.

High-dose ethanol intoxication decreases 1/f neural noise or scale-free neural activity in the resting state

Binge drinking is a frequent phenomenon in many western societies and has been associated with an increased risk of developing alcohol use disorder later in life. Yet, the effects of high-dose alcohol intoxication on neurophysiological processes are still quite poorly understood. This is particularly the case given that neurophysiological brain activity not only contains recurring (oscillatory) patterns of activity, but also a significant fraction of "scale-free" or arrhythmic dynamics referred to as 1/f type activity, pink noise, or 1/f neural noise. Neurobiological considerations suggest that it should be modulated by alcohol intoxication. To investigate this assumption, we collected resting state EEG data from n = 23 healthy young male subjects in a crossover design, where each subject was once tested sober and once tested while intoxicated (mean breath alcohol concentration of 1.1 permille ±0.2). Analyses of the 1/f neural dynamics showed that ethanol intoxication decreased resting state 1/f neural noise, as compared with a sober state. The effects were strongest when the eyes were closed and particularly reliable in the beta frequency band. Given that the dynamics of the beta band have been shown to strongly depend on GABA_A receptor neural transmission, this finding nicely aligns with the fact that ethanol increases GABAergic signaling. The study reveals a currently unreported effect of binge drinking on neurophysiological dynamics, which likely revealed a higher sensitivity for ethanol effects than most commonly considered measures of power in neural oscillations. Implications and applicability of these findings are discussed.

Evaluating the combined effect of alcohol-involved and un-helmeted riding on motorcyclist fatalities in Taiwan

BACKGROUND

Alcohol-involved riders tend to engage in other risk-taking behaviours such as un-helmeted riding which could further increases injury severity. The combined effect of alcohol-involved and un-helmeted riding on fatal injuries is rarely investigated. This study investigated the interaction effect between blood alcohol concentration and helmet use on fatal injuries.

METHODS

This study used the National Taiwan Traffic Crash Dataset for the period from 2011 to 2015. Data on road crashes involving a motorcycle and an automobile were extracted and analysed. Multiple logistic regression models were used to calculate the adjusted odds ratio (AOR). We calculated an interaction effect for blood alcohol concentration and helmet use based on STROBE guidelines.

RESULTS

There were a total of 669,292 motorcyclist casualties; among these casualties, 3459 (0.5 %) motorcyclists sustained fatal injuries. Alcohol-involved riders were 9.47 times (AOR = 9.47; 95 % CI = 8.75-10.25) more likely than sober ones to sustain fatal injuries. Alcohol-involved and un-helmeted riders were approximately 18 times (AOR = 18.1; CI: 15.9-20.4) more likely to sustain fatal injuries than sober and helmeted riders. Riders involved in head-on crashes and approach-turn motorcycle crashes had an increased probability of sustaining fatal injuries by 240 % (AOR = 3.4; 95 % CI = 2.91-4.09) and 132 % (AOR = 2.3; 95 % CI = 2.016-2.67), respectively.

CONCLUSIONS

This study found that alcohol-involved riding acts synergistically with un-helmeted riding to increase motorcyclist injury severity.

Heightened Exploratory Behavior Following Chronic Excessive Ethanol Drinking: Mediation by Neurotensin Receptor Type 2 in the Anterior Paraventricular Thalamus

BACKGROUND

Chronic, excessive alcohol drinkers, even without dependence, can exhibit changes in behavior and neurochemical systems. Identifying these changes and their relationship with one another could provide novel avenues for the prevention and treatment of alcohol use disorder. We recently demonstrated, in rats, that neurotensin (NTS) in the paraventricular thalamus (PVT) regulates excessive ethanol (EtOH) drinking. Here, we investigate the effects of chronic EtOH drinking on the PVT-NTS system and its contribution to EtOH-induced behavioral changes.

METHODS

We gave adult male Long-Evans rats 20% EtOH under the intermittent access 2-bottle-choice paradigm or maintained them on chow and water for up to 11 weeks. Prior to EtOH exposure and following several weeks of access, during acute abstinence, we tested these groups for multiple behaviors. In the 12th week, during acute abstinence, we examined gene expression and peptide levels of NTS and its receptors in the anterior and posterior subregions of the PVT. Finally, in chronic EtOH drinkers, during acute abstinence, we microinjected the NTS receptor type 2 (NTS2R) agonist, JMV-431, in the anterior PVT (aPVT) and examined subsequent EtOH intake and behavior.

RESULTS

Following chronic intermittent EtOH access, rats were classified by cluster analysis as high or low EtOH drinkers. High EtOH drinkers spent more time in the light chamber of a light-dark box and open arms of an elevated plus maze and entered fewer familiar holes in a hole-board apparatus. These differences were absent prior to EtOH exposure but were detectable as early as 4 weeks into drinking. Time in the light chamber following chronic drinking also predicted level of subsequent drinking. High EtOH drinkers also showed elevated protein levels of NTS2R in the aPVT, and pharmacological stimulation of aPVT NTS2R in low drinkers mimicked the increased time spent in the light chamber that was observed in high drinkers.

CONCLUSIONS

Our findings suggest that chronic, excessive, but not lower level, EtOH drinking induces heightened or flexible exploratory behavior, which predicts future EtOH drinking and is partly mediated by elevated NTS2R signaling in the aPVT. These EtOH-induced alterations represent adaptations that could perpetuate excessive drinking and lead to the development of EtOH dependence.

Alcohol Hangover Does Not Alter the Application of Model-Based and Model-Free Learning Strategies

Frequent alcohol binges shift behavior from goal-directed to habitual processing modes. This shift in reward-associated learning strategies plays a key role in the development and maintenance of alcohol use disorders and seems to persist during (early stages of) sobriety in at-risk drinkers. Yet still, it has remained unclear whether this phenomenon might be associated with alcohol hangover and thus also be found in social drinkers. In an experimental crossover design, n = 25 healthy young male participants performed a two-step decision-making task once sober and once hungover (i.e., when reaching sobriety after consuming 2.6 g of alcohol per estimated liter of total body water). This task allows the separation of effortful model-based and computationally less demanding model-free learning strategies. The experimental induction of alcohol hangover was successful, but we found no significant hangover effects on model-based and model-free learning scores, the balance between model-free and model-based valuation (ω), or perseveration tendencies (π). Bayesian analyses provided positive evidence for the null hypothesis for all measures except π (anecdotal evidence for the null hypothesis). Taken together, alcohol hangover, which results from a single binge drinking episode, does not impair the application of effortful and computationally costly model-based learning strategies and/or increase model-free learning strategies. This supports the notion that the behavioral deficits observed in at-risk drinkers are most likely not caused by the immediate aftereffects of individual binge drinking events.

Alcohol Hangover Differentially Modulates the Processing of Relevant and Irrelevant Information

Elevated distractibility is one of the major contributors to alcohol hangover-induced behavioral deficits. Yet, the basic mechanisms driving increased distractibility during hangovers are still not very well understood. Aside from impairments in attention and psychomotor functions, changes in stimulus-response bindings may also increase responding to distracting information, as suggested by the theory of event coding (TEC). Yet, this has never been investigated in the context of alcohol hangover. Therefore, we investigated whether alcohol hangover has different effects on target-response bindings and distractor-response bindings using a task that allows to differentiate these two phenomena. A total of n = 35 healthy males aged 19 to 28 were tested once sober and once hungover after being intoxicated in a standardized experimental drinking setting the night before (2.64 gr of alcohol per estimated liter of body water). We found that alcohol hangover reduced distractor-response bindings, while no such impairment was found for target-response bindings, which appeared to be unaffected. Our findings imply that the processing of distracting information is most likely not increased, but in fact decreased by hangover. This suggests that increased distractibility during alcohol hangover is most likely not caused by modulations in distractor-response bindings.

How high-dose alcohol intoxication affects the interplay of automatic and controlled processes

Binge drinking is an increasingly prevalent pattern of alcohol consumption that impairs top-down cognitive control to a much stronger degree than automatic response generation. Even though an imbalance of those two antagonistic processes fosters the development and maintenance of alcohol use disorders (AUDs), it has never been directly investigated how binge drinking affects the interaction of those two processes. We therefore assessed a sample of n = 35 healthy young men who were asked to perform a newly developed Simon Nogo paradigm once sober and once intoxicated (~1.2‰) in a balanced within-subject design. Additionally, an EEG was recorded to dissociate controlled and automatic cognitive subprocesses. The results demonstrate that alcohol seems to reduce top-down cognitive control. This control impairment was associated with changes in S-R mapping (reflected by a reduced parietal P3 amplitude), top-down response selection (reflected by modulations of lateralized readiness potentials), and (the evaluation of) response inhibition (reflected by modulations of the Nogo P3). In sharp contrast to this, automatic processing does not seem to be equally altered, as we found neither increases nor decreases in this domain. Most importantly, we also found that the interaction between control and automatisms might be less impaired by alcohol than control alone, which may help to overcome alcohol-induced response inhibition deficits. These "carryover" effects of control from one domain to the other could potentially prove beneficial in AUDs.

Alcohol Hangover Slightly Impairs Response Selection but not Response Inhibition

Alcohol hangover commonly occurs after an episode of heavy drinking. It has previously been demonstrated that acute high-dose alcohol intoxication reduces cognitive control, while automatic processes remain comparatively unaffected. However, it has remained unclear whether alcohol hangover, as a consequence of binge drinking, modulates the interplay between cognitive control and automaticity in a comparable way. Therefore, the purpose of this study was to investigate the effects of alcohol hangover on controlled versus automatic response selection and inhibition. N = 34 healthy young men completed a Simon Nogo task, once sober and once hungover. Hangover symptoms were experimentally induced by a standardized administration of alcoholic drinks (with high congener content) on the night before the hangover appointment. We found no significant hangover effects, which suggests that alcohol hangover did not produce the same functional deficits as an acute high-dose intoxication. Yet still, add-on Bayesian analyses revealed that hangover slightly impaired response selection, but not response inhibition. This pattern of effects cannot be explained with the current knowledge on how ethanol and its metabolite acetaldehyde may modulate response selection and inhibition via the dopaminergic or GABAergic system.

Young frequent binge drinkers show no behavioral deficits in inhibitory control and cognitive flexibility

Alcohol intoxication and abuse are well-known to cause impairments in executive functioning and control. Still, we know surprisingly little about individuals engaging in frequent binge drinking, even though they have an increased risk to develop an alcohol use disorder (AUD) later in life. As this risk has been suggested to be linked to (premorbid) executive deficits, we assessed changes in cognitive flexibility and inhibition with the help of a switching task and a stop-change task. Both paradigms had previously been shown to be modulated by alcohol, as well as by functional variations in dopaminergic and GABAergic neurotransmission. We employed an extreme group approach, where we compared pre-selected samples of frequent binge drinkers and non-frequent binge drinkers, all of which had stably pursued their respective consumption pattern for at least 3 years. In combination with Bayes analyses, our results showed that individuals engaging in frequent binge drinking showed no impairments of cognitive flexibility or inhibition, as compared to non-frequent binge drinkers. These observations suggest that frequent binge drinking alone is not associated with the cognitive control deficits commonly observed in AUD. Importantly, the investigated executive functions are known to be altered both during binge drinking and in individuals with AUD. It could hence be speculated that their intermittent consumption pattern prevents non-AUD frequent binge drinkers from the homeostatic counter-regulations of alcohol- and control-associated neurotransmitter systems that may be observed in AUD patients. Yet, this hypothesis still needs to be tested in future research, including studies that combine MR and molecular imaging.

Detrimental effects of a high-dose alcohol intoxication on sequential cognitive flexibility are attenuated by practice

It is well-known that alcohol impairs behavioral control and motor response inhibition, but it has remained rather unclear whether it also impairs cognitive inhibition. As automatized behavior is less vulnerable towards the detrimental effects of alcohol than cognitive control processes, potential cognitive inhibition deficits might however improve with training. We investigated the effect of an acute, binge-like alcohol intoxication in a balanced within-subjects design, asking n=32 healthy young males to perform a backward inhibition paradigm once sober and once while intoxicated (~1.1 ‰). To identify the underlying neurophysiological mechanisms, we analyzed stimulus- and response selection-related processes in neurophysiological data after Residue Iteration Decomposition (RIDE). Alcohol generally impaired behavioral task performance (accuracy and response times) during task switching. This was associated with impaired attentional processing of the task-relevant cue (reflected by reduced P1 and N1 amplitudes), which likely resulted in a larger need for reactive control at the later stage of response selection and control (reflected by increased fronto-central theta power). Without prior practice (~30 minutes), the intoxicated participants further struggled to overcome the cognitive inhibition of a previously relevant task set (reflected by a larger backward inhibition effect). This was linked to reduced posterior theta power, which reflects alcohol-induced impairments in working memory capacity and task set-relevant memory retrieval. As individuals with ~30 min task practice did not show the same alcohol-related deficit, it may be deduced that (partial) task set automatization via stimulus-response associations may help to reduce the detrimental effects of alcohol on cognitive inhibition during task switching.

Alcohol use and dementia: a systematic scoping review

BACKGROUND

Alcohol use has been identified as a risk factor for dementia and cognitive decline. However, some patterns of drinking have been associated with beneficial effects.

METHODS AND RESULTS

To clarify the relationship between alcohol use and dementia, we conducted a scoping review based on a systematic search of systematic reviews published from January 2000 to October 2017 by using Medline, Embase, and PsycINFO. Overall, 28 systematic reviews were identified: 20 on the associations between the level of alcohol use and the incidence of cognitive impairment/dementia, six on the associations between dimensions of alcohol use and specific brain functions, and two on induced dementias. Although causality could not be established, light to moderate alcohol use in middle to late adulthood was associated with a decreased risk of cognitive impairment and dementia. Heavy alcohol use was associated with changes in brain structures, cognitive impairments, and an increased risk of all types of dementia.

CONCLUSION

Reducing heavy alcohol use may be an effective dementia prevention strategy.

Alcohol Hangover Increases Conflict Load via Faster Processing of Subliminal Information

The detrimental effects of acute alcohol intoxication and long-term alcohol (ab)use on cognition are well-known. Yet, only little is known about the cognitive effects of an acute alcohol hangover, even though it might affect executive functions associated with workplace performance or driving skills. Given that alcohol hangover may increase the speed of information accumulation, we assessed the behavioral effects of conflict load (induced by a subliminal prime) on cognitive control, as assessed via the Flanker effect. We employed a counter-balanced within-subject design, where n = 25 healthy young males were tested once after a sober night and once after a night of experimentally induced heavy drinking of cheap brandy/red wine (2.6375 g alcohol per estimated liter of body water within 2–3 h). Alcohol hangover neither increased the cognitive conflicts induced by consciously processed distractors alone (i.e., the Flanker effect), nor modulated conflict adaptation (i.e., the Gratton effect). Instead, hangover potentiated the detrimental effects of conflicting subliminal primes on top-down cognitive conflicts. This effect was likely due to an increase in the speed of information accumulation from visual stimuli and the resulting increase in subliminal conflict load induced by incompatible primes. We further found the size of this effect to be positively correlated with age and subjective sleepiness during the hangover state, but the hangover effect remained significant even after correcting for those covariates. We further found no correlation of the behavioral effect with the subjective overall rating of hangover symptoms or the maximal breath alcohol concentration reached during prior intoxication. Taken together, our findings suggest that alcohol hangover may affect cognitive performance due to an increase in non-conscious processing of visual distractors. While the size of this effect might increase with age and sleepiness, it is not entirely dependent on those covariates and not necessarily related to subjective ratings of general hangover symptoms/impairment.

Serious mental illness and negative substance use consequences among adults on probation

BACKGROUND

Adults on probation are at greater risk of both using substances and having a mental disorder compared to the general population. Several theories explain the relationship between substance use and poor mental health. However, the interaction between substance use, mental health, and substance-related consequences is not well understood. A better understanding of this relationship may help treatment programs become more responsive to people with serious mental illness (SMI).

METHOD

The current study used interview data from 313 adults on probation who reported recent substance use. We examined associations between SMI risk, substance use, and substance use consequences.

RESULTS

A substantial proportion of the sample (37.5%) screened at risk of having a SMI. Adjusting for type and amount of substance use, those who screened at risk of having a SMI reported more negative substance use consequences. Significant interaction effects were observed between use of alcohol or opiates and SMI risk. Alcohol use was associated with more negative substance use consequences among those at risk of SMI, while opiate use was associated with more consequences among those not at risk.

CONCLUSIONS

Programs are sorely needed to identify and treat adults with comorbid substance use and mental health symptoms, particularly for adults in the justice system. Clinicians should carefully consider how mental health may interact with substance use to exacerbate consequences.

Low-level alcohol consumption during adolescence and its impact on cognitive control development

Adolescence is a critical period for maturation of cognitive control and most adolescents start experimenting with alcohol around that time. On the one hand, recent studies indicate that low control abilities predict future problematic alcohol use. On the other hand, binge drinking during young adulthood can (further) impair cognitive control. However, so far no study examined the effects of low-level alcohol use during adolescence. In the present longitudinal fMRI study, we therefore investigated the development of cognitive control in a community-based sample of 92 adolescents at ages 14, 16 and 18. Two different cognitive control functions, i.e. inhibition of pre-potent responses (operationalized by incongruence effects) and switching between different task sets, were measured within one task. Alcohol use in our sample was low (mean: 54 g/week at age 18). The study revealed that neither behavioural nor neural measures of cognitive control function at age 14 predicted alcohol use at age 18 but confirmed established predictors such as gender and personality. As expected, from age 14 to 18, cognitive control abilities were improving (decreased reaction times and/or errors), and activation of cognitive control networks (dorsal anterior cingulate cortex and pre-supplementary motor area) during incongruent trials increased. Unexpectedly, higher alcohol consumption during adolescence was associated with a more pronounced increase in cognitive performance and a smaller increase of neural activation when incongruent trials afforded inhibitory control. We conclude that low-level alcohol use during adolescence does not severely impair ongoing maturation of cognitive control abilities and networks.

The neural correlates of priming emotion and reward systems for conflict processing in alcoholics

Emotional dysregulation in alcoholism (ALC) may result from disturbed inhibitory mechanisms. We therefore tested emotion and alcohol cue reactivity and inhibitory processes using negative priming. To test the neural correlates of cue reactivity and negative priming, 26 ALC and 26 age-matched controls underwent functional MRI performing a Stroop color match-to-sample task. In cue reactivity trials, task-irrelevant emotion and alcohol-related pictures were interspersed between color samples and color words. In negative priming trials, pictures primed the semantic content of an alcohol or emotion Stroop word. Behaviorally, both groups showed response facilitation to picture cue trials and response inhibition to primed trials. For cue reactivity to emotion and alcohol pictures, ALC showed midbrain-limbic activation. By contrast, controls activated frontoparietal executive control regions. Greater midbrain-hippocampal activation in ALC correlated with higher amounts of lifetime alcohol consumption and higher anxiety. With negative priming, ALC exhibited frontal cortical but not midbrain-hippocampal activation, similar to the pattern observed in controls. Higher frontal activation to alcohol-priming correlated with less craving and to emotion-priming with fewer depressive symptoms. The findings suggest that neurofunctional systems in ALC can be primed to deal with upcoming emotion- and alcohol-related conflict and can overcome the prepotent midbrain-limbic cue reactivity response.

Earlier Alcohol Use Onset Predicts Poorer Neuropsychological Functioning in Young Adults

BACKGROUND

Neurodevelopment may be shaped by environmental factors such as alcohol intake. Over 20% of U.S. high school students begin drinking before age 14, and those who initiated drinking before age 14 are 4 times more likely to develop psychosocial, psychiatric, and substance use difficulties than those who began drinking after turning 20. Little is known, however, about how the age of alcohol use onset influences brain development.

METHODS

This study prospectively examined the effects of alcohol use onset age on neurocognitive functioning in healthy adolescent drinkers (N = 215). Youth were administered a neuropsychological battery before substance use initiation (M = 13.6 years, SD = 0.8) and on average 6.8 years later (M = 20.2 years, SD = 1.5). Hierarchical linear regressions examined if earlier ages of onset for first and regular (i.e., weekly) alcohol use adversely influenced neurocognition, above and beyond baseline neurocognition, substance use severity, and familial and social environment factors.

RESULTS

As hypothesized, an earlier age of first drinking onset (AFDO) predicted poorer performance in the domains of psychomotor speed and visual attention (ps<0.05, N = 215) and an earlier age of weekly drinking onset (AWDO) predicted poorer performances on tests of cognitive inhibition and working memory, controlling for baseline neuropsychological performance, drinking duration, and past-year marijuana use (ps<0.05, N = 127). No relationship between AFDO and AWDO was found with verbal learning and memory and visuospatial ability.

CONCLUSIONS

This is the first study to assess the association between age of adolescent drinking onset and neurocognitive performance using a comprehensive test battery. This study suggests that early onset of drinking increases risk for alcohol-related neurocognitive vulnerabilities and that initiation of any or weekly alcohol use at younger ages appears to be a risk factor for poorer subsequent neuropsychological functioning. Findings have important implications for public policies related to the legal drinking age and prevention programming. Further studies are needed to replicate these preliminary findings and better understand mediating processes and moderating conditions.

Effects of binge drinking and hangover on response selection sub-processes-a study using EEG and drift diffusion modeling

Effects of binge drinking on cognitive control and response selection are increasingly recognized in research on alcohol (ethanol) effects. Yet, little is known about how those processes are modulated by hangover effects. Given that acute intoxication and hangover seem to be characterized by partly divergent effects and mechanisms, further research on this topic is needed. In the current study, we hence investigated this with a special focus on potentially differential effects of alcohol intoxication and subsequent hangover on sub-processes involved in the decision to select a response. We do so combining drift diffusion modeling of behavioral data with neurophysiological (EEG) data. Opposed to common sense, the results do not show an impairment of all assessed measures. Instead, they show specific effects of high dose alcohol intoxication and hangover on selective drift diffusion model and EEG parameters (as compared to a sober state). While the acute intoxication induced by binge-drinking decreased the drift rate, it was increased by the subsequent hangover, indicating more efficient information accumulation during hangover. Further, the non-decisional processes of information encoding decreased with intoxication, but not during hangover. These effects were reflected in modulations of the N2, P1 and N1 event-related potentials, which reflect conflict monitoring, perceptual gating and attentional selection processes, respectively. As regards the functional neuroanatomical architecture, the anterior cingulate cortex (ACC) as well as occipital networks seem to be modulated. Even though alcohol is known to have broad neurobiological effects, its effects on cognitive processes are rather specific.

Addictions Neuroclinical Assessment: A reverse translational approach

Incentive salience, negative emotionality, and executive function are functional domains that are etiologic in the initiation and progression of addictive disorders, having been implicated in humans with addictive disorders and in animal models of addictions. Measures of these three neuroscience-based functional domains can capture much of the effects of inheritance and early exposures that lead to trait vulnerability shared across different addictive disorders. For specific addictive disorders, these measures can be supplemented by agent specific measures such as those that access pharmacodynamic and pharmacokinetic variation attributable to agent-specific gatekeeper molecules including receptors and drug-metabolizing enzymes. Herein, we focus on the translation and reverse translation of knowledge derived from animal models of addiction to the human condition via measures of neurobiological processes that are orthologous in animals and humans, and that are shared in addictions to different agents. Based on preclinical data and human studies, measures of these domains in a general framework of an Addictions Neuroclinical Assessment (ANA) can transform the assessment and nosology of addictive disorders, and can be informative for staging disease progression. We consider next steps and challenges for implementation of ANA in clinical care and research. This article is part of the Special Issue entitled "Alcoholism".

Binge Drinking Trajectory and Decision-Making during Late Adolescence: Gender and Developmental Differences

Objective: Impaired affective decision-making has been consistently related to alcohol dependence. However, less is known about decision-making and binge drinking (BD) in adolescents. The main goal of this longitudinal study was to determine the association between BD and decision-making from late adolescence to early adulthood. A second aim is to assess developmental changes and performance differences in males and females.

Method: An initial sample of 155 1st-year university students, (76 non-BDs, 40 females; and 79 BDs, 39 females), was followed prospectively over a 4-year period. The students were classified as stable non-BDs, stable BDs and ex-BDs according to their scores in item 3 of the AUDIT and the speed of alcohol consumption. Decision-making was assessed by the Iowa Gambling Task (IGT) three times during the study. Dependent variables were net gain and net loss. Results were analyzed using generalized linear mixed models.

Results: A stable BD pattern was not associated with either disadvantageous decision-making or sensitivity to loss frequency. Performance improved significantly in both genders over the study period, especially in the last blocks of the task. Females showed a higher sensitivity to loss frequency than males. No gender-related differences were observed in gains.

Conclusion: Performance in affective decision-making continues to improve in late adolescence, suggesting neuromaturational development in both genders. Females are more sensitive to loss frequency. Stable BD during late adolescence and emerging adulthood is not associated with deficits in decision-making. Poor performance of the IGT may be related to more severe forms of excessive alcohol consumption.

National Alcohol Survey of households in Trinidad and Tobago (NASHTT): Alcohol use in households

BACKGROUND

To determine the patterns of alcohol use among households in Trinidad and Tobago (T&T) and to estimate the association between alcohol use and negative psychological, social, or physical events experienced by the household.

METHODS

A convenience sample of 1837 households across T&T. We identified bivariate correlates of alcohol use, and heavy episodic drinking using chi-square and t-test analyses and used multivariable logistic regression to estimate adjusted associations between household alcohol use and experiences within the past 12 months adjusted for sociodemographic covariates.

RESULTS

One thousand five hundred two households had complete data for all variables (82% response rate). Nearly two thirds (64%) of households included alcohol users; 57% of household that consumed alcohol also reported heavy episodic drinking. Households that reported alcohol consumption were significantly more likely to report illnesses within the households, relationship problems, and behavioral and antisocial problems with children. Among households where a member was employed, those who consumed alcohol were nearly twice as likely (OR = 1.98; 95% confidence interval (CI) 1.03, 3.82) to have a household member call in sick to work and 2.9 times as likely (OR = 2.9; CI 1.19, 7.04) to have a household member suffer work related problems compared with households who reported not consuming alcohol.

CONCLUSIONS

Approximately two thirds of households in T&T reported using alcohol. These households were more likely to report psychological, physical, and social problems. These findings would support efforts to enforce current policies, laws, and regulations as well as new strategies to reduce the impact of harmful alcohol consumption on households in T&T.

Effects of drinking patterns on prospective memory performance in college students

OBJECTIVE

Traditional college students are at a critical juncture in the development of prospective memory (PM). Their brains are vulnerable to the effects of alcohol.

METHOD

There were 123 third and fourth year college students, 19-23 years old, who completed the Self-Rating Effects of Alcohol (SREA), Modified Timeline Follow-back (TFLB), Brief Young Adult Alcohol Consequences Scale (BYAACS), and Alcohol Effects Questionnaire (AEQ) once per month on a secure online database, as reported elsewhere (Dager et al., 2013). Data from the 6 months immediately before memory testing were averaged. In a single testing session participants were administered the Mini International Neuropsychiatric Interview-Diagnostic and Statistical Manual for Mental Disorders-Fourth Edition-Text Revision (MINI-DSM-IV-TR), measures of PM (event-based and time-based), and retrospective memory (RM). Based on the average score of six consecutive monthly responses to the SREA, TLFB, and AEQ, students were classified as nondrinkers, light drinkers, or heavy drinkers (as defined previously; Dager et al., 2013). Alcohol-induced amnesia (blackout) was measured with the BYAACS.

RESULTS

We found a relationship between these alcohol use classifications and time-based PM, such that participants who were classified as heavier drinkers were more likely to forget to perform the time-based PM task. We also found that self-reported alcohol-induced amnesia (blackouts) during the month immediately preceding memory testing was associated with lower performance on the event-based PM task. Participants' ability to recall the RM tasks suggested the PM items were successfully encoded even when they were not carried out, and we observed no relationship between alcohol use and RM performance.

CONCLUSION

Heavy alcohol use in college students may be related to impairments in PM. (PsycINFO Database Record

Reversal of alcohol-induced effects on response control due to changes in proprioceptive information processing

Recent research has drawn interest to the effects of binge drinking on response selection. However, choosing an appropriate response is a complex endeavor that usually requires us to process and integrate several streams of information. One of them is proprioceptive information about the position of limbs. As to now, it has however remained elusive how binge drinking affects the processing of proprioceptive information during response selection and control in healthy individuals. We investigated this question using neurophysiological (EEG) techniques in a response selection task, where we manipulated proprioceptive information. The results show a reversal of alcohol-induced effects on response control due to changes in proprioceptive information processing. The most likely explanation for this finding is that proprioceptive information does not seem to be properly integrated in response selection processes during acute alcohol intoxication as found in binge drinking. The neurophysiological data suggest that processes related to the preparation and execution of the motor response, but not upstream processes related to conflict monitoring and spatial attentional orienting, underlie these binge drinking-dependent modulations. Taken together, the results show that even high doses of alcohol have very specific effects within the cascade of neurophysiological processes underlying response control and the integration of proprioceptive information during this process.

Gender Differences in Risk Factors for Adolescent Binge Drinking and Implications for Intervention and Prevention

Alcohol use, particularly binge drinking (BD), is a major public health concern among adolescents. Recent national data show that the gender gap in alcohol use is lessening, and BD among girls is rising. Considering the increase in BD among adolescent girls, as well as females' increased risk of experiencing more severe biopsychosocial negative effects and consequences from BD, the current review sought to examine gender differences in risk factors for BD. The review highlights gender differences in (1) developmental-related neurobiological vulnerability to BD, (2) psychiatric comorbidity and risk phenotypes for BD, and (3) social-related risk factors for BD among adolescents, as well as considerations for BD prevention and intervention. Most of the information gleaned thus far has come from preclinical research. However, it is expected that, with recent advances in clinical imaging technology, neurobiological effects observed in lower mammals will be confirmed in humans and vice versa. A synthesis of the literature highlights that males and females experience unique neurobiological paths of development, and although there is debate regarding the specific nature of these differences, literature suggests that these differences in turn influence gender differences in psychiatric comorbidity and risk for BD. For one, girls are more susceptible to stress, depression, and other internalizing behaviors and, in turn, these symptoms contribute to their risk for BD. On the other hand, males, given gender differences across the lifespan as well as gender differences in development, are driven by an externalizing phenotype for risk of BD, in part, due to unique paths of neurobiological development that occur across adolescence. With respect to social domains, although social and peer influences are important for both adolescent males and females, there are gender differences. For example, girls may be more sensitive to pressure from peers to fit in and impress others, while male gender role stereotypes regarding BD may be more of a risk factor for boys. Given these unique differences in male and female risk for BD, further research exploring risk factors, as well as tailoring intervention and prevention, is necessary. Although recent research has tailored substance use intervention to target males and females, more literature on gender considerations in treatment for prevention and intervention of BD in particular is warranted.

Do Baseline Executive Functions Mediate Prospective Memory Performance under a Moderate Dose of Alcohol?

Prospective memory (PM) is memory for delayed intentions. While deleterious effects of acute doses of alcohol on PM have been documented previously using between-subjects comparisons, the current study adopted a single blind placebo-controlled within-subjects design to explore whether the extent to which alcohol-related impairments in PM are mediated by executive functions (EFs). To this end, 52 male social drinkers with no history of substance-related treatment were tested using two parallel versions of a clinical measure of PM (the Memory for Intentions Test; Raskin et al., 2010), and a battery of EF measures. Testing took place on two occasions, with the order of administration of the alcohol and placebo conditions being fully counterbalanced. Overall, PM was worse under alcohol and participants showed deficits on five of the six subscales making up the clinical test. Hierarchical multiple regression analyses demonstrated that EFs did not predict PM performance decrements overall but did predict performance when time cues were presented and when verbal responses were required. Phonemic fluency was the strongest of the EF predictors; a greater capacity to gain controlled access to information in long-term memory predicted a smaller difference between placebo- and alcohol-related performance on both the time cue and verbal response scales. PM is crucial to compliance with, and response to, both therapy programs and alcohol harm prevention campaigns. The results indicate that individual differences in cognitive function need to be taken into account when designing such interventions in order to increase their effectiveness.

Binge Drinkers Are Fast, Able to Stop - but They Fail to Adjust

Binge drinking leads to brain damage. However, at present few studies have taken into account the continuity in the binge drinking phenomenon, and treated binge drinking as a clearly separable category from other types of drinking patterns. The aim of the present study was to investigate whether severity of binge drinking can predict specific neurocognitive changes in healthy young adults. A total of 121 students aged 18 to 25 were assessed by means of the three last questions of the Alcohol Use Questionnaire combined into binge score. The binge score was entered as a predictor of cognitive performance of the CANTAB Stop Signal Task including reaction time, inhibition processing time, and response adjustment. Anxiety and depression symptoms were also measured. Binge score significantly predicted less adjustment following failures, and faster reaction times. Binge score did not predict inhibition performance. Symptoms of depression and anxiety were not significantly related to binge score. Binge drinking in healthy young adults predicts impairment in response adjustment and fast reaction time, but is unrelated to inhibition. The study supports the view that binge drinking is a continuous phenomenon, rather than discrete category, and the findings are possibly shedding light on why binge drinkers continue their drinking pattern despite negative consequences. (JINS, 2016, 22, 38-46).

Effects of alcohol-induced working memory decline on alcohol consumption and adverse consequences of use

RATIONALE

Alcohol use appears to decrease executive function acutely in a dose-dependent manner, and lower baseline executive function appears to contribute to problematic alcohol use. However, no studies, to our knowledge, have examined the relationship between individual differences in working memory (a subcomponent of executive function) after alcohol consumption and drinking behaviors and consequences.

OBJECTIVES

The current study assessed the relationship between drinking behavior, alcohol-related consequences, and alcohol-induced changes in working memory (as assessed by Trail Making Test-B).

METHOD

Participants recruited from the community (n = 41), 57.3 % male, mean age 39.2, took part in a three-session, within-subjects, repeated-measures design. Participants were administered a placebo, 0.4 g/kg, or 0.8 g/kg dose of alcohol. Working memory, past 30-day alcohol consumption, and consequences of alcohol use were measured at baseline; working memory was measured again after each beverage administration.

RESULTS

Poorer working memory after alcohol administration (controlling for baseline working memory) was significantly associated with a greater number of drinks consumed per drinking day. Additionally, we observed a significant indirect relationship between the degree of alcohol-induced working memory decline and adverse consequences of alcohol use, which was mediated through greater average drinks per drinking day.

CONCLUSIONS

It is possible that greater individual susceptibility to alcohol-induced working memory decline may limit one's ability to moderate alcohol consumption as evidenced by greater drinks per drinking day and that this results in more adverse consequences of alcohol use.

High-dose alcohol intoxication differentially modulates cognitive subprocesses involved in response inhibition

Aside from well-known physiological effects, high-dose alcohol intoxication (a.k.a. binge drinking) can lead to aversive social and legal consequences because response inhibition is usually compromised under the influence of alcohol. Although the behavioral aspects of this phenomenon were reported on extensively, the underlying neurophysiological mechanisms mediating this disinhibition are unclear. To close this gap, we used both behavioral and neurophysiological measures (event-related potentials, ERPs) to investigate which subprocesses of response inhibition are altered under the influence of high-dose alcohol intoxication. Using a within-subject design, we asked young healthy participants (n = 27) to complete a GO/NOGO task once sober and once intoxicated (approximately 1.2‰). During intoxication, high-dose alcohol effects were highest in a condition where the participants could not rely on automated stimulus-response mapping processes during response inhibition. In this context, the NOGO-P3 (ERP), that likely depends on dopaminergic signaling within mesocorticolimbic pathways and is thought to reflect motor inhibition and/or the evaluation of inhibitory processes, was altered in the intoxicated state. In contrast to this, the N2 component, which largely depends on nigrostriatal dopamine pathways and is thought to reflect inhibition on a pre-motor level, was not altered. Based on these results, we demonstrate that alcohol-induced changes of dopaminergic neurotransmission do not exert a global effect on response inhibition. Instead, changes are highly subprocess-specific and seem to mainly target mesocorticolimbic pathways that contribute to motor inhibition and the evaluation of such.

Adolescent heavy drinkers' amplified brain responses to alcohol cues decrease over one month of abstinence

INTRODUCTION

Heavy drinking during adolescence is associated with increased reactivity to alcohol related stimuli and to differential neural development. Alcohol cue reactivity has been widely studied among adults with alcohol use disorders, but little is known about the neural substrates of cue reactivity in adolescent drinkers. The current study aimed to identify changes in blood-oxygen level dependent (BOLD) signal during a cue reactivity task pre- and post-monitored abstinence from alcohol.

METHOD

Demographically matched adolescents (16.0-18.9 years, 54% female) with histories of heavy episodic drinking (HD; n=22) and light or non-drinking control teens (CON; n=16) were recruited to participate in a month-long study. All participants completed a functional Magnetic Resonance Imaging (fMRI) scan with an alcohol cue reactivity task and substance use assessments at baseline and after 28 days of monitored abstinence from alcohol and drugs (i.e., urine toxicology testing every 48-72 h). Repeated-measure analysis of variance (ANOVA) examined main effects of group, time, and group×time interactions on BOLD signal response in regions of interest defined by functional differences at baseline.

RESULTS

The HD group exhibited greater (p<.01) BOLD activation than CON to alcohol cues relative to neutral cues in all regions of interest (ROIs; bilateral striatum/globus pallidus, left anterior cingulate, bilateral cerebellum, and parahippocampal gyrus extending to the thalamus/substantia nigra) across time points. Group×time effects showed that HD exhibited greater BOLD activation to alcohol cues than CON at baseline in left anterior cingulate cortex and in the right cerebellar region, but these decreased to non-significance after one month of monitored abstinence.

CONCLUSIONS

In all ROIs examined, HD exhibited greater BOLD response than CON to alcohol relative to neutral beverage picture cues at baseline, indicating heightened cue reactivity to alcohol cues in heavy drinking adolescents prior to the onset of any alcohol use diagnosis. Across the majority of these brain regions, differences in BOLD response were no longer apparent following a month of abstinence, suggesting a decrease in alcohol cue reactivity among adolescent non-dependent heavy drinkers as a consequence of abstaining from alcohol. These results highlight the malleability of adolescent brain function despite no formal intervention targeting cue reactivity. Increased understanding of the neural underpinnings of cue reactivity could have implications for prevention and intervention strategies in adolescent heavy alcohol users.

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.

Altered expression of δGABAA receptors in health and disease

γ-Aminobutyric acid type A receptors that contain the δ subunit (δGABAA receptors) are expressed in multiple types of neurons throughout the central nervous system, where they generate a tonic conductance that shapes neuronal excitability and synaptic plasticity. These receptors regulate a variety of important behavioral functions, including memory, nociception and anxiety, and may also modulate neurogenesis. Given their functional significance, δGABAA receptors are considered to be novel therapeutic targets for the treatment of memory dysfunction, pain, insomnia and mood disorders. These receptors are highly responsive to sedative-hypnotic drugs, general anesthetics and neuroactive steroids. A further remarkable feature of δGABAA receptors is that their expression levels are highly dynamic and fluctuate substantially during development and in response to physiological changes including stress and the reproductive cycle. Furthermore, the expression of these receptors varies in pathological conditions such as alcoholism, fragile X syndrome, epilepsy, depression, schizophrenia, mood disorders and traumatic brain injury. Such fluctuations in receptor expression have significant consequences for behavior and may alter responsiveness to therapeutic drugs. This review considers the alterations in the expression of δGABAA receptors associated with various states of health and disease and the implications of these changes.

Alcohol abuse and ERP components in Go/No-go tasks using alcohol-related stimuli: impact of alcohol avoidance

Alcohol addictive behaviors are associated with a combination of deficits in executive functions, such as a weak response inhibition, and potent automatic appetitive responses to alcohol-related cues. The aim of the present study was to investigate behavioral responses and event-related potentials (ERPs) associated with specific response inhibition for alcohol-related cues. Thirty participants (15 heavy drinkers and 15 light drinkers) took part in the study. Response inhibition was assessed by a classical letter Go/No-go task and by a modified alcohol Go/No-go task. Participants were also classified as high and low alcohol avoiders. Results showed that heavy drinkers made more false alarms in the letter Go/No-go task. In the alcohol Go/No-go task, an absence of N200 amplitude anteriorization was found in heavy drinkers as compared to light drinkers. Participants with a high level of alcohol avoidance exhibited more false alarms, and higher N200 amplitude for the No-go trials as compared to the Go trials for alcohol-related cues. Higher P300 amplitude was observed in low alcohol avoiders for No-go as compared to Go trials. Therefore, a context involving alcohol-related cues disturbed inhibition capacities of high alcohol avoiders. These results suggest that the level of alcohol avoidance must be taken into account in studies investigating alcohol-related cognitive biases.

Cognitive control in alcohol use disorder: deficits and clinical relevance

Cognitive control refers to the internal representation, maintenance, and updating of context information in the service of exerting control over thoughts and behavior. Deficits in cognitive control likely contribute to difficulty in maintaining abstinence in individuals with alcohol use disorders (AUD). In this article, we define three cognitive control processes in detail (response inhibition, distractor interference control, and working memory), review the tasks measuring performance in these areas, and summarize the brain networks involved in carrying out these processes. Next, we review evidence of deficits in these processes in AUD, including both metrics of task performance and functional neuroimaging. Finally, we explore the clinical relevance of these deficits by identifying predictors of clinical outcome and markers that appear to change (improve) with treatment. We observe that individuals with AUD experience deficits in some, but not all, metrics of cognitive control. Deficits in cognitive control may predict clinical outcome in AUD, but more work is necessary to replicate findings. It is likely that performance on tasks requiring cognitive control improves with abstinence, and with some psychosocial and medication treatments. Future work should clarify which aspects of cognitive control are most important to target during treatment of AUD.

Larger mid-dorsolateral prefrontal gray matter volume in young binge drinkers revealed by voxel-based morphometry

Binge drinking or heavy episodic drinking is a high prevalent pattern of alcohol consumption among young people in several countries. Despite increasing evidence that binge drinking is associated with impairments in executive aspects of working memory (i.e. self-ordered working memory), processes known to depend on the mid-dorsolateral prefrontal cortex (Brodmann areas 46 and 9), less is known about the impact of binge drinking on prefrontal gray matter integrity. Here, we investigated the effects of binge drinking on gray matter volume of mid- dorsolateral prefrontal cortex in youths. We used voxel-based morphometry on the structural magnetic resonance images of subjects reporting a persistent (at least three years) binge drinking pattern of alcohol use (n = 11; age 22.43 ± 1.03) and control subjects (n = 21; age 22.18 ± 1.08) to measure differences in gray matter volume between both groups. In a region of interest analysis of the mid-dorsolateral prefrontal cortex, after co-varying for age and gender, we observed significantly larger gray matter volume in the left mid-dorsolateral prefrontal cortex (Brodmann areas 46 and 9) in binge drinkers in comparison with control subjects. Furthermore, there was a significant positive correlation between left mid-dorsolateral prefrontal cortex volume and Self-Ordered Pointing Test (SOPT) total errors score in binge drinkers. The left mid-dorsolateral prefrontal cortex volume also correlated with the quantity and speed of alcohol intake. These findings indicate that a repeated exposure to alcohol -that does not meet criteria for alcohol dependence- throughout post-adolescent years and young adulthood is linked with structural anomalies in mid-dorsolateral prefrontal regions critically involved in executive aspects of working memory.

Response inhibition toward alcohol-related cues using an alcohol go/no-go task in problem and non-problem drinkers

BACKGROUND

Previous results suggested that alcohol abusers and alcohol dependent patients show cognitive biases in the treatment of alcohol-related cues, especially approach and inhibition deficit biases. Response inhibition was often tested using the go/no-go task in which the participants had to respond as quickly as possible to a class of stimuli (go stimuli) while refraining from responding to another class of stimuli (no-go stimuli). Previous studies assessing specific response inhibition deficits in the process of alcohol-related cues obtained conflicting results. The aims of the present study were to clarify response inhibition for alcohol cues in problem and non-problem drinkers, male and female and to test the effect of alcohol brand logos.

METHODS

Thirty-six non-problem drinker and thirty-five problem drinker undergraduate students completed a modified alcohol go/no-go task using alcohol and neutral object pictures, with or without brand logos, as stimuli. An additional control experiment was carried out to check whether participants' awareness that the study tested their response to alcohol might have biased the results.

RESULTS

All participants, whether problem or non-problem drinkers, showed significantly shorter mean reaction times when alcohol pictures are used as go stimuli and significantly higher percentages of commission errors (false alarms) when alcohol pictures are used as no-go stimuli. Identical effects were obtained in the control experiment when participants were unaware that the study focused on alcohol. Shorter reaction times to alcohol-related cues were observed in problem drinkers relative to non-problem drinkers but only in the experimental condition with no brand logos on alcohol pictures. The addition of alcohol brand logos further reduced reaction times in light drinkers, thereby masking group differences. There was a tendency for female problem drinkers to show higher rates of false alarms for alcohol no-go stimuli, although this effect was only very close to statistical significance.

CONCLUSIONS

All participants exhibited a cognitive bias in the treatment of alcohol cues that might be related to the positive emotional value of such alcohol-related cues. Stronger cognitive biases in the treatment of alcohol cues were observed in problem drinkers, although differences between problem and non-problem drinkers were relatively small-scale and required specific experimental parameters to be uncovered. In particular, the presence of alcohol brand logos on visual alcohol cues was an important experimental parameter that significantly affected behavioral responses to such stimuli.