Neuropsychological assessment of impulsive behavior in abstinent alcohol-dependent subjects

Factors underlying the neurofunctional domains of the Addictions Neuroclinical Assessment assessed by a standardized neurocognitive battery

The Addictions Neuroclinical Assessment (ANA) is a neurobiologically-informed framework designed to understand the etiology and heterogeneity of Alcohol Use Disorder (AUD). Previous studies validated the three neurofunctional domains of ANA: Incentive Salience (IS), Negative Emotionality (NE) and Executive Function (EF) using secondary data. The present cross-sectional observational study assessed these domains in an independent, prospective clinical sample. Adults across the drinking spectrum (N = 300) completed the ANA battery, a standardized collection of behavioral tasks and self-report assessments. Factor analyses were used to identify latent factors underlying each domain. Associations between identified domain factors were evaluated using structural equation models. Receiver operating characteristics analyses were used to determine factors with the strongest ability to classify individuals with problematic drinking and AUD. We found (1) two factors underlie the IS domain: alcohol motivation and alcohol insensitivity. (2) Three factors were identified for the NE domain: internalizing, externalizing, and psychological strength. (3) Five factors were found for the EF domain: inhibitory control, working memory, rumination, interoception, and impulsivity. (4) These ten factors showed varying degrees of cross-correlations, with alcohol motivation, internalizing, and impulsivity exhibiting the strongest correlations. (5) Alcohol motivation, alcohol insensitivity, and impulsivity showed the greatest ability in classifying individuals with problematic drinking and AUD. Thus, the present study identified unique factors underlying each ANA domain assessed using a standardized assessment battery. These results revealed additional dimensionality to the ANA domains, bringing together different constructs from the field into a single cohesive framework and advancing the field of addiction phenotyping. Future work will focus on identifying neurobiological correlates and identifying AUD subtypes based on these factors.

The differential neural substrates for reward choice under gain-loss contexts and risk in alcohol use disorder: Evidence from a voxel-based meta-analysis

BACKGROUND

Making a risky decision is a complex process that involves the evaluation of both the values of the options and the associated risk level; this process is distinct from reward processing in gain versus loss contexts. Although disrupted reward processing in mesolimbic dopamine circuitry is suggested to underlie pathological incentive processing in patients with alcohol use disorder (AUD), the differential neural processes subserving these motivational tendencies for risk situations or gain/loss choices in decision-making have not been identified.

METHODS

To examine the common or distinct neural mechanisms in the evaluation of risk versus outcomes for AUD, we conducted two separate coordinate-based meta-analyses of functional neuroimaging studies by using Seed-Based d Mapping software to evaluate 13 studies investigating gain and loss processing and 10 studies investigating risky decision-making.

RESULTS

During gain and loss processing, relative to healthy controls, AUD patients showed reduced activation in the mesocortical-limbic circuit, including the orbital prefrontal cortex (OFC), dorsal striatum, insula, hippocampus, cerebellum, cuneus cortex and superior temporal gyrus, but hyperactivation in the inferior temporal gyrus and paracentral lobule (extending to the middle cingulate cortex (MCC) and precuneus). During decision-making under risk, AUD patients exhibited hypoactivity of the prefrontal and cingulate cortices, including the posterior cingulate cortex (extending to the MCC), middle frontal gyrus, medial prefrontal cortex, dorsolateral prefrontal cortex, OFC and anterior cingulate cortex.

CONCLUSIONS

Our results extend existing neurological evidence by showing that a reduced response in the mesocortical-limbic circuit is found in gain versus loss processing, with decreased responsivity in cortical regions in risk decision-making. Our results implicate dissociable neural circuit responses for gain-loss processing and risk decision-making, which contribute to a better understanding of the pathophysiological mechanism underlying nondrug incentive and risk processing in individuals with AUD.

Risky Decision-Making in Adults with Alcohol Use Disorder-A Systematic and Meta-Analytic Review

Alcohol use disorder (AUD) forms a major health concern and is the most common substance use disorder worldwide. The behavioural and cognitive deficits associated with AUD have often been related to impairments in risky decision-making. The aim of this study was to examine the magnitude and type of risky decision-making deficits of adults with AUD, as well as to explore the potential mechanisms behind these deficits. To this end, existing literature comparing risky decision-making task performance of an AUD group to a control group (CG) was systematically searched and analysed. A meta-analysis was performed to address overall effects. In total, 56 studies were included. In the majority of studies (i.e., 68%), the performance of the AUD group(s) deviated from the CG(s) on one or more of the adopted tasks, which was confirmed by a small to medium pooled effect size (Hedges' g = 0.45). This review therefore provides evidence of increased risk taking in adults with AUD as compared to CGs. The increased risk taking may be due to deficits in affective and deliberative decision-making. Making use of ecologically valid tasks, future research should investigate whether risky decision-making deficits predate and/or are consequential to the addiction of adults with AUD.

Determinants of health-related quality of life in recently detoxified patients with severe alcohol use disorder

Background

Health-related quality of life (HRQoL) is an important clinical outcome in Alcohol Use Disorder (AUD) and is considered as a relevant indicator of treatment success. While a better understanding of the factors affecting HRQoL would enable to adjust patients’ care to favour treatment outcome, the determinants of HRQoL in AUD remain unclear. This study aims at describing HRQoL in AUD patients and at identifying its best predictors.

Methods

53 recently detoxified patients with severe AUD (sAUD) underwent a cognitive assessment and filled in a HRQoL questionnaire dedicated to AUD patients (Alcohol Quality of Life Scale; AQoLS), as well as questionnaires concerning socio-demographics, alcohol history, sleep quality, depression, anxiety and impulsivity. 38 healthy controls (HC) underwent the same assessment (except AQoLS) in order to identify the altered cognitive and clinical variables that could potentially be determinants of HRQoL in sAUD.

Results

sAUD patients reported that alcohol affects their HRQoL mainly in the “negative emotions”, “control”, “relationships”, and “sleep” domains. Compared to HC, they were impaired on episodic memory, working memory, executive functions, and processing speed tasks. They also reported lower sleep quality, higher depression, anxiety and impulsivity. No association was found between AQoLS total score and socio-demographics, cognitive performance, or sleep quality in patients. We found a significant correlation between HRQoL and depression/anxiety as well as impulsivity. Anxiety and impulsivity were indeed the only significant predictors of HRQoL, explaining 47.7% of the variance.

Conclusion

Anxiety and impulsivity are crucial determinants of HRQoL in recently detoxified sAUD patients. Since anxiety and impulsivity are frequent issues in addiction and especially in AUD, they should be particularly considered by clinicians to favour treatment outcomes.

Effect of alcohol use disorder family history on cognitive function

BACKGROUND

Alcohol use disorder (AUD) is associated with cognitive deficits but little is known to what degree this is caused by genetically influenced traits, i.e. endophenotypes, present before the onset of the disorder. The aim of the current study was to investigate to what degree family history (FH) of AUD is associated with cognitive functions.

METHODS

Case-control cross-sectional study at an outpatient addiction research clinic. Treatment-seeking AUD patients (n = 106) were compared to healthy controls (HC; n = 90), matched for age and sex. The HC group was further subdivided into AUD FH positive (FH+; n = 47) or negative (FH-; n = 39) based on the Family Tree Questionnaire. Participants underwent psychiatric and substance use assessments, completed the Barratt Impulsiveness Scale and performed a comprehensive battery of neuropsychological tests assessing response inhibition, decision making, attention, working memory, and emotional recognition.

RESULTS

Compared to HC, AUD patients exhibited elevated self-rated impulsivity (p < 0.001; d = 0.62), as well as significantly poorer response inhibition (p = 0.001; d = 0.51), attention (p = 0.021; d = 0.38) and information gathering in decision making (p = 0.073; d = 0.34). Similar to AUD patients, FH+ individuals exhibited elevated self-rated impulsivity (p = 0.096; d = 0.46), and in addition significantly worse future planning capacity (p < 0.001; d = 0.76) and prolonged emotional recognition response time (p = 0.010; d = 0.60) compared to FH-, while no other significant differences were found between FH+ and FH-.

CONCLUSIONS

Elevated impulsivity, poor performance in future planning and emotional processing speed may be potential cognitive endophenotypes in AUD. These cognitive domains represent putative targets for prevention strategies and treatment of AUD.

Investigation on the Attention Deficit Hyperactivity Disorder Effect on Infatuation and Impulsivity in Adolescents

Introduction

In this study, we proposed to investigate the association between infatuation/passionate love and impulsivity in a context of potential high impulsivity: adolescents with attention deficit and hyperactivity/impulsivity (ADHD) diagnosis compared with typically developing adolescents.

Methods

Impulsivity was understood as an exploratory and a sensation seeking behavior, a trend to engage in novel and exciting activities, and was evaluated using the UPPS Impulsive Behavior Scale. Eighty-one adolescents from 13-to-18 years old with and without ADHD diagnosis were compared regarding infatuation intensity, behavioral impulsivity, and social and educational profiles.

Results

After correlation analysis, we found association between higher scores on the infatuation intensity with fewer years of formal education, heightened urgency and sensation seeking. On the other hand, using the generalized equation model, we showed that the association of passionate love with behavioral urgency and sensation seeking did not change in the presence of the ADHD diagnosis.

Conclusion

The understanding of the relationship of impulsivity with infatuation might help to clarify why some population groups show an increased risk for many negative social outcomes.

The relationship between impaired control, impulsivity, and alcohol self-administration in nondependent drinkers

Impaired control over drinking is a significant marker of alcohol use disorder (AUD), and a potential target of intervention (Heather, Tebbutt, Mattick, & Zamir, 1993; Leeman, Toll, Taylor, & Volpicelli, 2009). Impaired control may be related to, but conceptually distinct from, impulsivity (Leeman, Patock-Peckham, & Potenza, 2012; Leeman, Ralevski, et al., 2014). However, the relationship between impaired control, impulsivity, and alcohol consumption, particularly in nondependent drinkers is less clear. This study aimed to characterize these relationships using a free-access intravenous alcohol self-administration (IV-ASA) paradigm in nondependent drinkers (N = 48). Results showed individuals with higher self-reported impaired control achieved higher blood alcohol concentrations (BAC) during the IV-ASA session and reported greater hedonic subjective responses to alcohol. Higher impaired control was also associated with greater positive urgency and reward sensitivity. Moderated-mediation analysis showed that the relationship between positive urgency and peak BAC was mediated by impaired control, and partially moderated by subjective alcohol response. These findings highlight the critical role of impaired control over drinking on alcohol consumption and subjective responses in nondependent drinkers. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Widespread Cognitive Deficits in Alcoholism Persistent Following Prolonged Abstinence: An Updated Meta-analysis of Studies That Used Standardised Neuropsychological Assessment Tools

Objective

This study presents an updated meta-analysis replicating the study of (Stavro, K., Pelletier, J., & Potvin, S. (2013). Widespread and sustained cognitive deficits in alcoholism: A meta-analysis. Addiction Biology, 18, 203–213. doi:10.1111/j.1369-1600.2011.00418.x) regarding the cognitive functioning of alcoholics as a function of time abstinent.

Methods

A total of 34 studies (including a total of 2,786 participants) that met pre-determined inclusion and exclusion criteria were included in the analyses. The alcoholics were categorised into recently detoxified alcoholics (0–31 days sober), alcoholics 32–365 days sober and alcoholics &gt;365 days sober consistent with the previous study. The current study employed more stringent control on the tests included in the analysis to include only those tasks described in contemporary neuropsychological test compendia. Forty-seven percent of the papers surveyed were not include in the previous meta-analysis.

Results

The results indicated that there was a diffuse and pervasive pattern of cognitive deficit among recently detoxified alcoholics and that these deficits, particularly with regard to memory functioning, persisted even in longer term abstinent alcoholics. This was inconsistent with the prior meta-analysis which contended that significant cognitive recovery was possible after as little as 1 year.

Conclusion

The persisting cognitive deficits were noted across a wide range of cognitive functions, supporting the notion of a diffuse rather than a specific compromise of cognition in alcoholism following discontinuation, as measured using standardised neuropsychological tests. Limitations on the finding included the fact that it was a cross-sectional rather than a longitudinal analysis, was subject to heterogeneity of method, had low representation of females in the samples, and had fewer studies of long-term sober samples.

Increased reward-oriented impulsivity in older bipolar patients: A preliminary study

OBJECTIVE

Impulsivity is a well-established trait of bipolar disorder (BD) that persists across mood phases. It is, however, still unknown whether, in BD, impulsivity remains stable or varies in intensity over the lifespan. This cross-sectional study compared impulsive behavior in older euthymic BD patients and healthy individuals using a range of self-rating and behavioral measures of impulsivity.

METHODS

28 BD patients (56.07 ± 4.08 years, 16 women) and 15 healthy controls (HC; 55.1 ± 3.95 years, 6 women) were administered the Barratt Impulsivity Scale (BIS) and selected tasks of the Cambridge Neuropsychological Test Automated Batter (CANTAB) reflecting impulsivity. Multivariate analysis of variance controlled for age compared impulsivity measures across BD and HC.

RESULTS

BD patients displayed poor decision making, risk taking, and increased delay aversion. Other measures of impulsivity such as response inhibition, sustained cognitive control, and BIS scores were, overall, comparable between BD and HC.

CONCLUSIONS

These preliminary findings suggest that, in BD, aspects of impulsivity related to reward-based decision making persist into late adulthood. Large scale, longitudinal studies are needed to evaluate the relationship of age to impulsivity over time, and explore the link between impulsivity and illness progression in elderly individuals with BD.

Dysregulated Glycine Signaling Contributes to Increased Impulsivity during Protracted Alcohol Abstinence

Persons with alcoholism who are abstinent exhibit persistent impairments in the capacity for response inhibition, and this form of impulsivity is significantly associated with heightened relapse risk. Brain-imaging studies implicate aberrant prefrontal cortical function in this behavioral pathology, although the underlying mechanisms are not understood. Here we present evidence that deficient activation of glycine and serine release in the ventral medial prefrontal cortex (vmPFC) contributes to increased motor impulsivity during protracted abstinence from long-term alcohol exposure. Levels of 12 neurotransmitters were monitored in the rat vmPFC during the performance of a challenging variant of the five-choice serial reaction time task (5-CSRTT) in which alcohol-exposed rats exhibit excessive premature responding. Following long-term ethanol exposure, rats showed blunted task-related recruitment of vmPFC glycine and serine release, and the loss of an inverse relationship between levels of these neurotransmitters and premature responding normally evident in alcohol-naive subjects. Intra-vmPFC administration of the glycine transport inhibitor ALX5407 prevented excessive premature responding by alcohol-exposed rats, and this was reliant on NMDA glycine site availability. Alcohol-exposed rats and controls did not differ in their premature responding and glycine and serine levels in vmPFC during the performance of the standard 5-CSRTT. Collectively, these findings provide novel insight into cortical neurochemical mechanisms contributing to increased impulsivity following long-term alcohol exposure and highlight the NMDA receptor coagonist site as a potential therapeutic target for increased impulsivity that may contribute to relapse risk.SIGNIFICANCE STATEMENT Persons with alcoholism demonstrate increased motor impulsivity during abstinence; however, the neuronal mechanisms underlying these behavioral effects remain unknown. Here, we took advantage of an animal model that shows deficiencies in inhibitory control following prolonged alcohol exposure to investigate the neurotransmitters that are potentially responsible for dysregulated motor impulsivity following long-term alcohol exposure. We found that increased motor impulsivity is associated with reduced recruitment of glycine and serine neurotransmitters in the ventromedial prefrontal cortex (vmPFC) cortex in rats following long-term alcohol exposure. Administration of glycine transport inhibitor ALX5407 in the vmPFC alleviated deficits in impulse control.

Executive Functions, Memory, and Social Cognitive Deficits and Recovery in Chronic Alcoholism: A Critical Review to Inform Future Research

Alcoholism is a complex and dynamic disease, punctuated by periods of abstinence and relapse, and influenced by a multitude of vulnerability factors. Chronic excessive alcohol consumption is associated with cognitive deficits, ranging from mild to severe, in executive functions, memory, and metacognitive abilities, with associated impairment in emotional processes and social cognition. These deficits can compromise efforts in initiating and sustaining abstinence by hampering efficacy of clinical treatment and can obstruct efforts in enabling good decision making success in interpersonal/social interactions, and awareness of cognitive and behavioral dysfunctions. Despite evidence for differences in recovery levels of selective cognitive processes, certain deficits can persist even with prolonged sobriety. Herein is presented a review of alcohol-related cognitive impairments affecting component processes of executive functioning, memory, and the recently investigated cognitive domains of metamemory, social cognition, and emotional processing; also considered are trajectories of cognitive recovery with abstinence. Finally, in the spirit of critical review, limitations of current knowledge are noted and avenues for new research efforts are proposed that focus on (i) the interaction among emotion-cognition processes and identification of vulnerability factors contributing to the development of emotional and social processing deficits and (ii) the time line of cognitive recovery by tracking alcoholism's dynamic course of sobriety and relapse. Knowledge about the heterochronicity of cognitive recovery in alcoholism has the potential of indicating at which points during recovery intervention may be most beneficial.

Are self-rated and behavioural measures of impulsivity in bipolar disorder mainly related to comorbid substance use problems?

INTRODUCTION

Impulsivity is a multidimensional feature observed in bipolar disorder (BD) and substance use disorder (SUD). We previously found a relationship between SUD and risk taking in BD. It is still unclear whether self-rated and behavioral impulsivity measures differ between BD with and without comorbid SUD, or are specific to BD.

METHODS

93 adults with BD with comorbid SUD, 91 BD without SUD, and 93 healthy controls (HC) were administered the Barratt Impulsivity Scale (BIS), the Behavioral Inhibition/Behavioral Activation System Scale (BIS/BAS), and the Cambridge Neuropsychological Test Automated Battery. Analyses compared impulsivity measures across groups controlling for age. Discriminant function analyses (DFA) assessed the combination of variables effectively predicting group membership.

RESULTS

BD displayed increased BIS, BIS/BAS scores, reduced performance on the Cambridge Gambling and Rapid Visual Processing, and Affective Go/No-Go tasks compared to HC. Comparisons between BD with and without SUD showed increased BIS Motor impulsiveness. The overall predictive power of DFA was weak.

CONCLUSIONS

Some facets of impulsivity are a core trait of BD and are partially independent from the presence of SUD. Motor impulsiveness may be distinctive of BD+SUD. More research is needed to understand the role of impulsive behaviors as risk factors for relapse in SUD.

Do alcohol-dependent patients show different neural activation during response inhibition than healthy controls in an alcohol-related fMRI go/no-go-task?

RATIONALE

Alcohol dependence is associated with impaired response inhibition and heightened cue reactivity towards alcohol-related stimuli. Several brain areas, but mainly prefrontal structures, have been linked to response inhibition in addiction. This study aimed at combining both aspects: salience of drug-associated cues and response inhibition using a go/no-go task with alcohol-associated stimuli during functional magnetic resonance imaging (fMRI).

OBJECTIVES

Nineteen abstinent alcohol-dependent patients (ADP) and 21 healthy control subjects (HC) were compared on blood oxygen level-dependent (BOLD) responses during successful inhibition of no-go stimuli and successful reactions to go stimuli.

RESULTS

ADP and HC did not significantly differ in their behavioural performance in the task. However, both groups performed worse during the inhibition of alcoholic-associated stimuli compared to neutral stimuli. On the neural level, ADP displayed enhanced BOLD activity relative to HC during successful response inhibition in several areas involved in visual processing, cognitive and impulse control, including occipital structures, anterior cingulate gyrus, medial frontal gyrus and medial orbitofrontal cortex.

CONCLUSIONS

We interpret these findings as a possible compensation strategy for impaired cognitive processing. Furthermore, the results underline the impact of salience of alcohol-related stimuli on response inhibition, which seems to affect both ADP and HC.

Individual differences in voluntary alcohol intake in rats: relationship with impulsivity, decision making and Pavlovian conditioned approach

RATIONALE

Alcohol use disorder (AUD) has been associated with suboptimal decision making, exaggerated impulsivity, and aberrant responses to reward-paired cues, but the relationship between AUD and these behaviors is incompletely understood.

OBJECTIVES

This study aims to assess decision making, impulsivity, and Pavlovian-conditioned approach in rats that voluntarily consume low (LD) or high (HD) amounts of alcohol.

METHODS

LD and HD were tested in the rat gambling task (rGT) or the delayed reward task (DRT). Next, the effect of alcohol (0-1.0 g/kg) was tested in these tasks. Pavlovian-conditioned approach (PCA) was assessed both prior to and after intermittent alcohol access (IAA). Principal component analyses were performed to identify relationships between the most important behavioral parameters.

RESULTS

HD showed more optimal decision making in the rGT. In the DRT, HD transiently showed reduced impulsive choice. In both LD and HD, alcohol treatment increased optimal decision making in the rGT and increased impulsive choice in the DRT. PCA prior to and after IAA was comparable for LD and HD. When PCA was tested after IAA only, HD showed a more sign-tracking behavior. The principal component analyses indicated dimensional relationships between alcohol intake, impulsivity, and sign-tracking behavior in the PCA task after IAA.

CONCLUSIONS

HD showed a more efficient performance in the rGT and DRT. Moreover, alcohol consumption enhanced approach behavior to reward-predictive cues, but sign-tracking did not predict the level of alcohol consumption. Taken together, these findings suggest that high levels of voluntary alcohol intake are associated with enhanced cue- and reward-driven behavior.

A failure of suppression within the default mode network in depressed adolescents with compulsive internet game play

BACKGROUND

Individuals who are chronic, compulsive video game players experience an elevated incidence of major depression. Excessive or problematic game play can interact with depression clinically, and may magnify impulsive behavior associated with video gaming.

METHODS

Functional brain imaging was performed during a Wisconsin Card Sorting Test (WCST) task in 42 healthy control and 95 volunteers seeking treatment for compulsive video game playing, including 60 participants without major depression (pure internet gaming disorder, pure IGD) and 35 participants comorbid with major depression (IGD+MDD).

RESULTS

In response to the WCST in contrast to fixation, activation was observed in canonical brain attentional networks including bilateral intraparietal sulcus, frontal eye fields, and middle temporal cortical regions as well as dorsolateral prefrontal, inferior parietal and anterior insula, anterior cingulate cortex in all participants. For WCST>Fixation contrasts, the IGD+MDD group exhibited greater relative activation within the left hippocampus, compared to healthy control participants. For WCST>Fixation contrasts, the IGD+MDD group exhibited greater relative activation within the left hippocampus and the right parahippocampal gyrus immediately posterior to the hippocampus, compared to the pure IGD group.

CONCLUSIONS

In cohorts of individuals with a history of compulsive internet game play, individuals with depression showed failure to suppress default mode network activity during an attentionally demanding task, compared to individuals without depression, including comparison groups with and without a history of compulsive video gaming. This reduced suppression of the brain regions within the default mode network may be a consequence of depressive neurophysiology or represent a predisposition for depression within compulsive game players.

Exercise training - A beneficial intervention in the treatment of alcohol use disorders?

BACKGROUND

A growing body of evidence suggests that exercise training may have multiple beneficial effects in individuals with mental health or substance use disorders. Yet, relatively little knowledge exists regarding the benefits of exercise training to augment treatment for alcohol use disorders (AUDs).

PURPOSE

The purpose of this narrative review is to present a summary of the growing body of published literature supporting exercise training as a treatment strategy for individuals with AUDs. We will provide evidence on the myriad of ways in which exercise may exert a positive effect on AUD outcomes including stress, anxiety, impulsivity, and depression. Further, we will explore how these mechanisms share common neurobiological pathways. The role of exercise in enhancing the social environment and increasing individual self-efficacy to reduce excess and/or inappropriate alcohol consumption will also be discussed.

DISCUSSION

We will conclude with a description of completed investigations involving exercise training and provide suggestions for next steps in this innovative field of study.

Delta, theta, and alpha event-related oscillations in alcoholics during Go/NoGo task: Neurocognitive deficits in execution, inhibition, and attention processing

Higher impulsivity observed in alcoholics is thought to be due to neurocognitive functional deficits involving impaired inhibition in several brain regions and/or neuronal circuits. Event-related oscillations (EROs) offer time-frequency measure of brain rhythms during perceptual and cognitive processing, which provide a detailed view of neuroelectric oscillatory responses to external/internal events. The present study examines evoked power (temporally locked to events) of oscillatory brain signals in alcoholics during an equal probability Go/NoGo task, assessing their functional relevance in execution and inhibition of a motor response. The current study hypothesized that increases in the power of slow frequency bands and their topographical distribution is associated with tasks that have increased cognitive demands, such as the execution and inhibition of a motor response. Therefore, it is hypothesized that alcoholics would show lower spectral power in their topographical densities compared to controls. The sample consisted of 20 right-handed abstinent alcoholic males and 20 age and gender-matched healthy controls. Evoked delta (1.0-3.5Hz; 200-600ms), theta (4.0-7.5Hz; 200-400ms), slow alpha (8.0-9.5Hz; 200-300ms), and fast alpha (10.0-12.5Hz; 100-200ms) ERO power were compared across group and task conditions. Compared to controls, alcoholics had higher impulsiveness scores on the Barrett Impulsiveness Scale (BIS-11) and made more errors on Go trials. Alcoholics showed significantly lower evoked delta, theta, and slow alpha power compared to controls for both Go and NoGo task conditions, and lower evoked fast alpha power compared to controls for only the NoGo condition. The results confirm previous findings and are suggestive of neurocognitive deficits while executing and suppressing a motor response. Based on findings in the alpha frequency ranges, it is further suggested that the inhibitory processing impairments in alcoholics may arise from inadequate early attentional processing with respect to the stimulus related aspects/semantic memory processes, which may be reflected in lower posterio-temporal evoked fast alpha power. It can thus be concluded that alcoholics show neurocognitive deficits in both execution and suppression of a motor response and inadequate early attentional processing with respect to the semantic memory/stimulus related aspects while suppressing a motor response.

Altered performance in a rat gambling task after acute and repeated alcohol exposure

RATIONALE

A bidirectional relationship between alcohol use disorder (AUD) and deficits in impulse control and decision making has been suggested. However, the mechanisms by which neurocognitive impairments predispose to, or result from AUD remain incompletely understood.

OBJECTIVES

The aim of this study is to gain more insight in the effects of alcohol exposure on decision making and impulse control. We used two modified versions of the rat gambling task (rGT) that differ in the net gain and the punishment magnitude associated with the different response options.

METHODS

In experiment 1, we assessed the effects of acute alcohol treatment (0-0.8 g/kg) on rGT performance. In experiment 2, we determined the effects of alcohol on rGT acquisition (15 sessions, 0.6 g/kg). Next, these animals were challenged with alcohol (0-1.0 g/kg) prior to rGT sessions.

RESULTS

Acute alcohol treatment suppressed baseline performance in both rGT versions but only modestly altered decision making. Treatment with alcohol during acquisition increased risky choices in the rGT version that involved larger punishment and blunted the reduction in win-shift behavior during acquisition in both rGT versions. Moreover, rats treated with alcohol during acquisition showed an increase in premature and perseverative responding upon subsequent alcohol challenges (0-1.0 g/kg) and were less sensitive to the behavioral suppressant effects of alcohol.

CONCLUSIONS

Our results show that repeated alcohol exposure alters decision making during rGT acquisition and reduces the ability to adjust choice behavior on the basis of feedback. In addition, repeated alcohol exposure unmasks its behavioral disinhibitory effects in the rGT. Impaired responsiveness to choice feedback and behavioral disinhibition may contribute to the development of AUD.

Deficits in behavioural inhibition in substance abuse and addiction: a meta-analysis

AIMS

Deficits in behavioural inhibitory control are attracting increasing attention as a factor behind the development and maintenance of substance dependence. However, evidence for such a deficit is varied in the literature. Here, we synthesised published results to determine whether inhibitory ability is reliably impaired in substance users compared to controls.

METHODS

The meta-analysis used fixed-effects models to integrate results from 97 studies that compared groups with heavy substance use or addiction-like behaviours with healthy control participants on two experimental paradigms commonly used to assess response inhibition: the Go/NoGo task, and the Stop-Signal Task (SST). The primary measures of interest were commission errors to NoGo stimuli and stop-signal reaction time in the SST. Additionally, we examined omission errors to Go stimuli, and reaction time in both tasks. Because inhibition is more difficult when inhibition is required infrequently, we considered papers with rare and equiprobable NoGo stimuli separately.

RESULTS

Inhibitory deficits were apparent for heavy use/dependence on cocaine, MDMA, methamphetamine, tobacco, and alcohol (and, to a lesser extent, non-dependent heavy drinkers), and in pathological gamblers. On the other hand, no evidence for an inhibitory deficit was observed for opioids or cannabis, and contradictory evidence was observed for internet addiction.

CONCLUSIONS

The results are generally consistent with the view that substance use disorders and addiction-like behavioural disorders are associated with impairments in inhibitory control. Implications for treatment of substance use are discussed, along with suggestions for future research arising from the limitations of the extant literature.

Impaired response inhibition in the rat 5 choice continuous performance task during protracted abstinence from chronic alcohol consumption

Impaired cognitive processing is a hallmark of addiction. In particular, deficits in inhibitory control can propel continued drug use despite adverse consequences. Clinical evidence shows that detoxified alcoholics exhibit poor inhibitory control in the Continuous Performance Task (CPT) and related tests of motor impulsivity. Animal models may provide important insight into the neural mechanisms underlying this consequence of chronic alcohol exposure though pre-clinical investigations of behavioral inhibition during alcohol abstinence are sparse. The present study employed the rat 5 Choice-Continuous Performance Task (5C-CPT), a novel pre-clinical variant of the CPT, to evaluate attentional capacity and impulse control over the course of protracted abstinence from chronic intermittent alcohol consumption. In tests conducted with familiar 5C-CPT conditions EtOH-exposed rats exhibited impaired attentional capacity during the first hours of abstinence and impaired behavioral restraint (increased false alarms) during the first 5d of abstinence that dissipated thereafter. Subsequent tests employing visual distractors that increase the cognitive load of the task revealed significant increases in impulsive action (premature responses) at 3 and 5 weeks of abstinence, and the emergence of impaired behavioral restraint (increased false alarms) at 7 weeks of abstinence. Collectively, these findings demonstrate the emergence of increased impulsive action in alcohol-dependent rats during protracted alcohol abstinence and suggest the 5C-CPT with visual distractors may provide a viable behavioral platform for characterizing the neurobiological substrates underlying impaired behavioral inhibition resulting from chronic intermittent alcohol exposure.

When self-report diverges from performance: the usage of BIS-11 along with neuropsychological tests

Impulsivity has been fractionated into multiple independent, but correlated, components. Personality and neuropsychological studies have consistently shown its multidimensional nature. Each theoretical approach uses different techniques such as self-report questionnaires and neuropsychological tests to assess impulsivity, respectively. Our main objective was to investigate if there is evidence of convergent validity for impulsivity as assessed by both types of measures. We administered the Barratt Impulsivity Scale 11 and two neuropsychological tests (Iowa Gambling Task and Continuous Performance Task) to 266 participants to measure inhibition control and non-planning impulsivity dimensions. Results from an exploratory factorial analysis and group comparison indicated there was little evidence of convergent validity between the two types of measures. These findings are discussed in terms of impulsivity as a multi-factorial construct as well as the specific instruments used for assessment. Implications for psychological theory and impulsivity assessment were also proposed.

Alpha-synuclein deletion decreases motor impulsivity but does not affect risky decision making in a mouse Gambling Task

RATIONALE

There is evidence to support the role of alpha-synuclein in motor impulsivity, but the extrapolation of this finding to other types of impulsivity remains to be elucidated.

OBJECTIVE

This study aims to investigate the role of alpha-synuclein in choice impulsivity/risky decision-making by means of a mouse version of the Iowa Gambling Task (mIGT).

METHODS

Two strains of mice that differ in the expression of the alpha-synuclein gene, the C57BL/6JOlaHsd (HA) and C57BL/6J (CR), were tested in the mIGT. HA mice differ from their CR ancestors in possessing a chromosomal deletion resulting in the loss of two genes: snca, encoding alpha-synuclein and mmrn1, encoding multimerin-1. Mice were trained in the mIGT until a stable pattern of responding was achieved and then the acute effects of ethanol and cocaine in choice preference were investigated.

RESULTS

No differences between the strains were evident in risky decision-making in any of the experiments, but HA mice showed consistently reduced levels of premature responding in comparison with CR mice, confirming the reduced motor impulsivity found in a previous study. Ethanol did not modify the percentage of advantageous choices in either strain, while cocaine increased the risky choice behaviour by increasing the percentage of disadvantageous choices in both strains.

CONCLUSIONS

We provide further evidence for the involvement of alpha-synuclein in motor impulsivity and suggest that alpha-synuclein does not play a role in risky decision-making as evaluated in the mIGT.

Impulsivity and substance-related attentional bias: a meta-analytic review

BACKGROUND

Previous research demonstrates the role of attentional bias in addictive behaviors. Impulsivity is thought to affect the strength of attentional biases, and thus, attentional biases might be one mechanism by which impulsivity affects addictive behaviors. However, whether or not impulsivity is related to attentional biases across different conceptualizations of impulsivity and attentional biases has yet to be examined as an initial test of such causal models.

METHODS

The authors completed a meta-analysis of 13 published research studies examining the relationship between substance-related attentional bias and different conceptualizations of impulsivity.

RESULTS

There was a small and significant effect size between impulsivity and substance-related attentional bias (r=0.20), which was moderated by impulsivity measurement type (Qb=5.91, df=1, p<0.05): there was a stronger relationship between behavioral impulsivity and substance-related attentional bias (r=0.22) than trait impulsivity and substance-related attentional bias (r=0.10). Different components of behavioral impulsivity and trait impulsivity did not affect the relationship.

CONCLUSIONS

This study is the first systematic and empirical demonstration of the relationship between substance-related attentional bias and impulsivity and suggests viability of future examinations of casual models relating these constructs. Since trait and behavioral conceptualizations differentially relate to substance-related attentional bias, the current review further supports research suggesting how disaggregation of multidimensional constructs can lead to more robust relationships.

The association between low alcohol use and traffic risk behaviors among Brazilian college students

Although there are a large number of studies focused on binge drinking and traffic risk behaviors (TRB), little is known regarding low levels of alcohol consumption and its association to TRB. The aim of this cross-sectional study is to examine the association of low to moderate alcohol intake pattern and TRB in college students in Brazil. 7037 students from a National representative sample were selected under rigorous inclusion criteria. All study participants voluntarily fulfilled a structured, anonymous, and self-questionnaire regarding alcohol and drug use, social-demographic data, and TRB. Alcohol was assessed according to the average number of alcoholic units consumed on standard occasions over the past 12 months. The associations between alcohol intake and TRB were summarized with odds ratio and their confidence interval obtained from logistic regression. Compared with abstainers students who consumed only one alcohol unit had the risk of being a passenger in a car driven by a drunk driver increased by almost four times, students who reported using five or more units were increased by almost five times the risk of being involved in a car crash. Compared with students who consumed one alcohol unit, the risk of driving under the influence of alcohol increased four times in students using three alcohol units. Age group, use of illicit drugs, employment status, gender, and marital status significantly influenced occurrence of TRB among college students. Our study highlights the potential detrimental effects of low and moderate pattern of alcohol consumption and its relation to riding with an intoxicated driver and other TRB. These data suggest that targeted interventions should be implemented in order to prevent negative consequences due to alcohol use in this population.

Dopaminergic genes modulate response inhibition in alcohol abusing adults

Compulsion in alcohol use disorders (AUD) has been attributed to impairment in response inhibition. Because genes that regulate dopamine (DA) have been implicated not only for risk for AUD but also for impulsivity based on behavioral studies, we set out to examine the underlying neural mechanisms associated with these effects. We collected functional magnetic resonance imaging images on 53 heavy drinking but otherwise healthy adults while performing the Go/NoGo task. We predicted that genetic variants previously reported in the literature to be associated with substance abuse, specifically the DRD2 rs1799732 and DRD4 VNTR, will modulate neural processes underlying response inhibition. Our results showed differential neural response for the DRD4 VNTR during successful inhibition in the inferior frontal gyrus (IFG) (cluster-corrected P<0.05, z=1.9). Similarly, DRD2 rs1799732 groups were significantly different in the precuneus and cingulate gyrus during successful response inhibition (cluster-corrected P<0.05, z=1.9). These findings provide further evidence for the role of DAergic genes in modulating neural response in areas that underlie response inhibition and self-monitoring processes. Variants within these genes appear to influence processes related to impulsive behavior, which may increase one's risk for alcohol abuse and dependence.

Responses to novelty and vulnerability to cocaine addiction: contribution of a multi-symptomatic animal model

Epidemiological studies have revealed striking associations between several distinct behavioral/personality traits and drug addiction, with a large emphasis on the sensation-seeking trait and the associated impulsive dimension of personality. However, in human studies, it is difficult to identify whether personality/behavioral traits actually contribute to increased vulnerability to drug addiction or reflect psychobiological adaptations to chronic drug exposure. Here we show how animal models, including the first multi-symptomatic model of addiction in the rat, have contributed to a better understanding of the relationships between different subdimensions of the sensation-seeking trait and different stages of the development of cocaine addiction, from vulnerability to initiation of cocaine self-administration to the transition to compulsive drug intake. We argue that sensation seeking predicts vulnerability to use cocaine, whereas novelty seeking, akin to high impulsivity, predicts instead vulnerability to shift from controlled to compulsive cocaine use, that is, addiction.

Are executive function and impulsivity antipodes? A conceptual reconstruction with special reference to addiction

RATIONALE

Although there is considerable interest in how either executive function (EF) or impulsivity relate to addiction, there is little apparent overlap between these research areas.

OBJECTIVES

The present paper aims to determine if components of these two constructs are conceptual antipodes--widely separated on a shared continuum.

METHODS

EFs and impulsivities were compared and contrasted. Specifically, the definitions of the components of EF and impulsivity, the methods used to measure the various components, the populations of drug users that show deficits in these components, and the neural substrates of these components were compared and contrasted.

RESULTS

Each component of impulsivity had an antipode in EF. EF, however, covered a wider range of phenomena, including compulsivity.

CONCLUSIONS

Impulsivity functions as an antipode of certain components of EF. Recognition of the relationship between EF and impulsivity may inform the scientific inquiry of behavioral problems such as addiction. Other theoretical implications are discussed.

Comorbidades psiquiátricas em dependentes químicos em abstinência em ambiente protegido

O objetivo desta pesquisa foi verificar a frequência de comorbidades psiquiátricas, utilizando Mini International Neuropsychiatric Interview, em diferentes grupos de dependentes químicos em abstinência, em ambiente protegido, classificados de acordo com o tipo de droga utilizada: (1) grupo controle (n = 37); (2) dependentes em abstinência de álcool (n = 8); (3) dependentes em abstinência de álcool, maconha e crack/cocaína (n = 24); e (4) dependentes em abstinência de múltiplas substâncias psicoativas (n=25), ou seja, indivíduos que faziam uso de vários tipos de drogas sem apresentar uma droga de escolha. Participaram 94 homens, com idade média de 30,41 anos (DP = 9,88). O período de abstinência variou entre 30 e 240 dias. A maioria dos participantes tinha baixa escolaridade e era solteira. Os resultados apontaram maior ocorrência de psicopatologias e risco de suicídio nos grupos formados por pacientes com histórico de consumo múltiplo de substâncias, sugerindo a importância da avaliação de outros transtornos associados à dependência química.

Delayed transition from ambiguous to risky decision making in alcohol dependence during Iowa Gambling Task

It has been demonstrated that alcohol-dependent patients exhibit decision-making deficits, particularly, hypersensitivity to reward and executive dysfunction. Yet, how the impaired motivational process and executive dysfunction in the patients affect decisions under ambiguity and risk with different degrees of uncertainty is little known. To investigate the neuropsychological origin of the impaired decision making under uncertainty in alcohol dependence, we administered the Iowa Gambling Task (IGT), Game of Dice Task (GDT) and Wisconsin Card Sorting Test (WCST) to 23 alcohol-dependent patients and 21 healthy subjects, and calculated the correlations between the task performances. We found that the patients showed poor performance in all three tasks compared with the healthy subjects. Moreover, correlations between performances on the GDT and the later trials of the IGT were delayed in alcohol-dependent patients when compared with healthy subjects. There is also a significant correlation between performances of earlier trials of the IGT and the WCST in the patients. These findings suggest that executive dysfunction in alcohol-dependent patients hampers appropriate estimation of probability distributions of possible alternatives, leading to a delayed transition from ambiguous to risky conditions in the Iowa Gambling Task.

Effects of acute administration of nicotine, amphetamine, diazepam, morphine, and ethanol on risky decision-making in rats

RATIONALE

Most individuals can accurately assess the risks and rewards associated with choice alternatives and decide accordingly; however, drug users often display maladaptive decision-making, such that choices are biased toward excessively risky options.

OBJECTIVE

The purpose of this study was to investigate the effects of a range of drugs of abuse on risky decision-making.

METHODS

Male Long-Evans rats were trained in the Risky Decision-Making Task, in which they chose between two levers, one which produced a small, "safe" food reward and the other which produced a large, "risky" food reward. The large reward was accompanied by the risk of a mild footshock, the probability of which increased over the course of each test session (0%, 25%, 50%, 75%, and 100%).

RESULTS

Nicotine (0.6 mg/kg) and amphetamine (1.5 mg/kg) caused a significant decrease in choice of the large risky reward (decreased risk taking). Diazepam (1.0 mg/kg) caused a significant increase in choice of the large risky reward (increased risk taking), whereas morphine (3.0 mg/kg) caused only a trend toward increased choice of the large risky reward. Ethanol had no effect on choice behavior.

CONCLUSIONS

These results show that acute administration of drugs of abuse can modulate risk taking in a drug-specific manner, either increasing or decreasing preference for highly rewarding, but risky, options.

Avaliação da memória operacional fonológica e impulsividade de usuários de drogas atendidos em um Centro de Atenção Integrada à Saúde Mental

OBJETIVO: avaliar a memória operacional fonológica e relacionar com a impulsividade de pacientes em tratamento no Centro de Atenção Integrada à Saúde Mental. MÉTODO: 29 usuários: 21 do gênero masculino e 8 do feminino, usuários de substâncias psicoativas, com 37,9±10,5 anos de idade e 10,59±3,53 anos de escolaridade; e 30 voluntários: 19 do gênero masculino e 11 do feminino, com 32,4±11,9 anos de idade e 11,07±3,29 anos de escolaridade, sem histórico psiquiátrico ou de dependência química foram convocados à avaliação de: 1) memória operacional para palavras e pseudo-palavras; 2) impulsividade em seus fatores de segunda ordem (impulsividade atencional, motora e de não planejamento). RESULTADOS: o desempenho dos usuários de substâncias psicoativas na avaliação da memória em comparação ao grupo controle foi pior tanto no span auditivo de palavras e pseudo-palavras como também no número total de recordação de palavras e pseudo-palavras. Na avaliação da impulsividade, os usuários apresentaram escores elevados em contraposição aos sujeitos controle em todos os subtipos de impulsividade, inclusive no total. Na análise de correlação dos dados não foram encontradas relações entre os escores de impulsividade e memória. CONCLUSÃO: : este padrão de respostas indica comprometimento da memória operacional fonológica provavelmente independente do alto nível de impulsividade apresentado pelos usuários de drogas. Estas análises contribuem para propor estratégias de tratamento direcionadas às alterações detectadas.

Impulse control and related disorders in Parkinson's disease patients treated with bilateral subthalamic nucleus stimulation: a review

Recently, impulse control and related disorders including punding and the dopamine dysregulation syndrome (DDS) have been increasingly recognized in treated patients with Parkinson's disease (PD). Especially the impulse control disorders (ICD) such as pathological gambling, hypersexuality, compulsive eating and buying may have dramatic repercussions on family, personal and professional life. Drug replacement therapy (DRT) is believed to play an important role in the onset of these behavioral disturbances. Although deep brain stimulation (DBS) of the subthalamic nucleus (STN) might be a therapeutic option for those patients with DRT-related behavior, it may also induce ICD. So far, little is known about the relationship between STN DBS and impulse control and related disorders. Our aim was to review the current knowledge on this relationship in PD patients. The available studies showed that stimulation of the STN is associated with both favorable and negative outcome in terms of impulse control and related disorders. Preoperative disorders may resolve or improve after STN DBS, but these can also worsen or show no change at all. Moreover, STN DBS can also reveal or even induce ICD. Possible explanations for this variability are proposed and suggestions for clinical management are given.

Impulsivity and the 5-HTTLPR polymorphism in a non-clinical sample

Background

Impulsivity has been associated with serotonergic system functions. However, few researchers have investigated the relationship between a polymorphism in the promoter of the serotonin transporter gene (5-HTTLPR) and the different components of impulsivity in a non-clinical population. The aim of this study was to investigate the relationship between a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) and the different components of impulsivity in a non-clinical population.

Methodology/Principal Findings

We administered two neuropsychological tests, the Continuous Performance Task and the Iowa Gambling Task, to 127 healthy participants to measure their levels of motor, attentional and non-planning impulsivity. Then, these participants were grouped by genotype and gender, and their scores on impulsivity measures were compared. There were no significant differences between group scores on attentional, motor and non-planning impulsivity.

Conclusions/Significance

Our results suggest that 5-HTTLPR genotype is not significantly associated with subsets of impulsive behavior in a non-clinical sample when measured by neuropsychological tests. These findings are discussed in terms of the sensitivity of neuropsychological tests to detect impulsivity in a non-clinical population and the role of gender and race in the relationship between the 5-HTTLPR and impulsivity.

Translational research in addiction: toward a framework for the development of novel therapeutics

The development of novel substance use disorder (SUD) therapeutics is insufficient to meet the medical needs of a growing SUD patient population. The identification of translatable SUD models and tests is a crucial step in establishing a framework for SUD therapeutic development programs. The present review begins by identifying the clinical features of SUDs and highlights the narrow regulatory end-point required for approval of a novel SUD therapeutic. A conceptual overview of dependence is provided, followed by identification of potential intervention targets in the addiction cycle. The main components of the addiction cycle provide the framework for a discussion of preclinical models and their clinical analogs, all of which are focused on isolated behavioral end-points thought to be relevant to the persistence of compulsive drug use. Thus, the greatest obstacle to successful development is the gap between the multiplicity of preclinical and early clinical end-points and the regulatory end-point of sustained abstinence. This review proposes two pathways to bridging this gap: further development and validation of the preclinical extended access self-administration model; inclusion of secondary end-points comprising all of the measures highlighted in the present discussion in Phase 3 trials. Further, completion of the postdictive validation of analogous preclinical and clinical assays is of high priority. Ultimately, demonstration of the relevance and validity of a variety of end-points to the ultimate goal of abstinence will allow researchers to identify truly relevant therapeutic mechanisms and intervention targets, and establish a framework for SUD therapeutic development that allows optimal decision-making and resource allocation.

Decision-making deficits linked to real-life social dysfunction in crack cocaine-dependent individuals

Crack cocaine-dependent individuals (CCDI) present abnormalities in both social adjustment and decision making, but few studies have examined this association. This study investigated cognitive and social performance of 30 subjects (CCDI × controls); CCDI were abstinent for 2 weeks. We used the Social Adjustment Scale (SAS), Wisconsin Card Sorting Test (WCST), and Iowa Gambling Task (IGT). Disadvantageous choices on the IGT were associated with higher levels of social dysfunction in CCDI, suggesting the ecological validity of the IGT. Social dysfunction and decision making may be linked to the same underlying prefrontal dysfunction, but the nature of this association should be further investigated. 

Tradução e adaptação cultural da Barratt Impulsiveness Scale (BIS-11) para aplicação em adultos brasileiros

OBJETIVOS: Os objetivos deste estudo foram traduzir, adaptar culturalmente e verificar a equivalência literal, semântica e idiomática da Barratt Impulsiveness Scale (BIS-11), que avalia a presença de manifestações da impulsividade tendo como base o modelo teórico proposto por Ernst Barratt. MÉTODOS: Inicialmente, a versão original em inglês da BIS-11 foi traduzida para o português por seis pesquisadores bilíngues. Em seguida, foi realizada uma tradução reversa para o inglês por uma tradutora de origem norte-americana. As versões original, traduzida e retraduzida foram avaliadas por um comitê de juízes especialistas, os quais emitiram pareceres com as observações pertinentes, o que culminou em uma versão final traduzida da BIS-11. As versões original e traduzida foram aplicadas em duas amostras da população geral com proficiência na língua inglesa, a fim de investigar a equivalência literal, semântica e idiomática da versão traduzida por meio de análises de correlação. CONCLUSÃO: Os resultados das análises quantitativas indicaram que a versão final do instrumento é satisfatória.