Heightened Impulsivity: Associated with Family History of Alcohol Misuse, and a Consequence of Alcohol Intake

The Continuing Challenges of Studying Parallel Behaviours in Humans and Animal Models

The use of animal models continues to be essential for carrying out research into clinical phenomena, including addiction. However, the complexity of the clinical condition inevitably means that even the best animal models are inadequate, and this may go some way to account for the apparent failures of discoveries from animal models, including the identification of potential novel therapies, to translate to the clinic. We argue here that it is overambitious and misguided in the first place to attempt to model complex, multifacetted human disorders such as addiction in animals, and especially in rodents, and that all too frequently "validity" of such models is limited to superficial similarities, referred to as "face validity", that reflect quite different underlying phenomena and biological processes from the clinical situation. Instead, a more profitable approach is to identify (a) well-defined intermediate human behavioural phenotypes that reflect defined, limited aspects of, or contributors to, the human clinical disorder, and (b) to develop animal models that are homologous with those discrete human behavioural phenotypes in terms of psychological processes, and underlying neurobiological mechanisms. Examples of past and continuing weaknesses and suggestions for more limited approaches that may allow better homology between the test animal and human condition are made.

Relationship between two forms of impulsivity in mice at baseline and under acute and sub-chronic atomoxetine treatment

RATIONALE

Impulsivity is a symptom of various mental disorders, including attention deficit hyperactivity disorder (ADHD), bipolar disorder, and addiction. Impulsivity is not a unitary construct, but is present in different forms, yet only a few rodent studies have explored the relationship between these forms within individual subjects.

OBJECTIVES

In this study, we compared behaviors representing two impulsivity forms, delay discounting (choice impulsivity) and premature responding (waiting impulsivity), within the same mice.

METHODS

C57BL/6J male mice were concurrently trained and tested in the delay discounting task and the rodent continuous performance test in a counterbalanced design. The effects of the ADHD medication atomoxetine were tested in both tasks, after both acute (0.3-5.0 mg/kg) and sub-chronic (0.3 mg/kg twice daily for seven days) administration.

RESULTS

There was no correlation between the two impulsivity forms at baseline. Acute atomoxetine treatment (1, 3, and 5 mg/kg) significantly reduced premature responding. Furthermore, sub-chronic treatment with 0.3 mg/kg of atomoxetine caused a stable decrease in premature responding. Atomoxetine had no significant effect on delay discounting after acute or sub-chronic administration, although the acute administration of 1 mg/kg showed a trend towards increasing delay discounting.

CONCLUSIONS

The present results support that delay discounting and premature responding represent two different forms of impulsivity that show dissimilar responses to atomoxetine treatment. The consistency with findings in humans lends support to the translatability of the results in mice.

Multidimensional Impulsive Personality Traits Mediate the Effect of Parent Substance Use Disorder on Adolescent Alcohol and Cannabis Use

Theory suggests that behavioral undercontrol mediates the effect of parental substance disorder on offspring substance use, but no studies have tested multidimensional impulsive personality traits as mechanisms of risk. Adolescents (N = 392; 48% female) from a multigenerational study of familial alcohol disorder self-reported impulsive personality traits via the UPPS-P (M_age = 16.09; Range = 13-19) and alcohol/cannabis frequency one year later. The UPPS-P assesses negative and positive urgency (i.e., rash action in a negative or positive mood state), lack of premeditation (i.e., lack of planning/forethought), lack of perseverance (i.e., inability to finish tedious/boring tasks), and sensation seeking (i.e., thrill seeking/risk taking). Parent substance disorder was assessed via diagnostic interviews. Two-part hurdle models tested predictors of any substance use (i.e., binary part) and frequency of use (i.e., continuous part). Parent substance disorder was indirectly associated with any alcohol/cannabis use (binary part) and higher cannabis frequency (continuous part) through negative urgency. Parental substance disorder was associated with higher alcohol frequency through a lack of premeditation. Sensation seeking was associated with any alcohol/cannabis use but unrelated to parental substance disorder. Despite indirect effects, strong effects of parental substance disorder on substance use remained. The findings are discussed in terms of theory and public health implications.

Extreme Binge Drinking During Adolescence: Associations With Subsequent Substance Use Disorders in American Indian and Mexican American Young Adults

OBJECTIVE

This study collected retrospective data on adolescent binge drinking (ABD) (5 drinks for boys, 4 for girls per occasion at least once per month) and/or extreme adolescent binge drinking (EABD) (10 or more drinks per occasion at least once per month) and tested for associations with demographic and diagnostics variables including alcohol and other substance use disorders (AUD/SUD).

METHODS

Cross-sectional data were collected from young adult (age 18-30 yrs) American Indians (AI) (n = 534) and Mexican Americans (MA) (n = 704) using a semi-structured diagnostic instrument.

RESULTS

Thirty percent (30%) of the sample reported ABD and 21% reported EABD. Those having had monthly ABD were more likely to be AI and have less education; those having had EABD were more likely to be AI, male, younger, have less education and lower economic status compared to participants without ABD. ABD/EABD was associated with higher impulsivity, a family history of AUD, and lower level of response to alcohol (ORs = 1.0-2.0), as well as with adult AUD (ORs = 3.7-48), other substance use disorders (ORs = 3.5-9), and conduct disorder/ antisocial personality disorder (ORs = 2.0-2.6), but not with anxiety/depression. Monthly EABD further increased the odds of AUD/SUD.

CONCLUSIONS

Although binge drinking was more common in AI compared to MA, there were little effects of race in individual risk factor analyses. Monthly ABD and EABD were common among these AI/MA as adolescents, and, as with other ethnic groups, these drinking patterns resulted in highly significant increases in the odds of developing alcohol and other substance use disorders in young adulthood.

Young age and the risk of violent behaviour in people with severe mental disorders: prospective, multicentre study

Background

During adolescence and young adulthood people appear to be more prone to violent behaviour. A greater tendency to violent behaviour appears to be associated with hyperactivity, impulsivity and low tolerance for frustration and provocation in social settings.

Aims

This prospective cohort study aimed to evaluate rates of violent behaviour among young people with mental disorders, compared with older age groups.

Method

A total of 340 individuals with severe mental disorders (125 living in residential facilities and 215 out-patients) were evaluated at baseline with the SCID-I and II, Brief Psychiatric Rating Scale, Specific Level of Functioning scale, Brown–Goodwin Lifetime History of Aggression scale, Buss–Durkee Hostility Inventory, Barratt Impulsiveness Scale and State–Trait Anger Expression Inventory-2. Aggressive behaviour was rated every 15 days with the Modified Overt Aggression Scale (MOAS).

Results

The sample comprised 28 individuals aged 18–29 years, 202 aged 30–49 and 110 aged 50 and over. Younger age was associated with a personality disorder diagnosis, substance use disorder, being single and employed. These results were confirmed even controlling for the gender effect. The patterns of the cumulative MOAS mean scores showed that younger (18–29 years old) individuals were significantly more aggressive than older (≥50) ones (P < 0.001).

Conclusions

This study highlights how young age in people with severe mental disorders is correlated with higher levels of impulsivity, anger and hostility, confirming previous analyses. Our results may assist clinicians in implementing early interventions to improve anger and impulsivity control to reduce the risk of future aggressive behaviours.

The Development of Externalizing and Internalizing Behaviors Among Youth With or Without a Family History of Substance Use Disorder: The Indirect Effects of Early-Life Stress and Impulsivity

Youth with a family history of substance use disorder (FH+) are more prone to have externalizing and internalizing problems compared to youth without a family history of substance use disorder (FH-), increasing the likelihood of later maladjustment. However, mechanisms for this association remain understudied. In this longitudinal study, we examined if FH+ youth are more likely to experience early-life stressors (ELS), which in turn would increase impulsivity and the expression of externalizing and internalizing behaviors. Data were collected from youth and a parent (n = 386) during a baseline assessment (age 10-12 years) and every six months when the youth was 13-16 years old. In support of the primary hypothesis, FH+ youth reported higher levels of externalizing and internalizing behaviors through ELS to impulsivity providing a developmental pathway through which FH+ youth are more prone to externalizing and internalizing problems.

Time perception and alcohol use: A systematic review

Attentional, executive, and memory processes play a pivotal role in time perception. As acute or chronic alcohol consumption influences these processes, it should also modify time perception. We systematically reviewed and critically assessed all existing studies on time perception among alcohol drinkers, following the PICOS procedure and PRISMA guidelines. We selected 31 articles, distributed across four populations (i.e., alcohol intoxication, binge/heavy drinking, severe alcohol use disorder [SAUD], and Korsakoff syndrome). Several studies suggested the overestimation or underestimation of time during alcohol intoxication. No direct effect of binge/heavy drinking was observed on time perception, while studies on SAUD reported conflicting results. Participants with Korsakoff syndrome exhibited globally impaired time perception and marked deficits in associated cognitive abilities. This systematic review suggests that alcohol consumption affects time perception only when specific cognitive processes are depleted. However, due to the methodological limitations related to existing studies, no firm conclusion can be drawn. Guidelines and perspectives to advance the field are proposed.

Experimental tasks of behavioral risk taking in alcohol administration studies: A systematic review

Research on emerging adults shows this population exhibits the highest rates of alcohol use and engages in the riskiest of behaviors (Boyer, 2006; Fromme, Corbin, & Kruse, 2008). Among experimental paradigms, prior reviews have established an increase in behavioral risk taking while under the influence of alcohol (Moskowitz & Robinson, 1988; Martin et al., 2013; Weafer & Fillmore, 2016). Previous research highlighted the importance of alcohol dose on behavioral risk taking and the lack of agreement on which psychometric tools are most accurate in assessing behavioral risk taking (Beulow & Blaine, 2015; King, Toule, De Wit, & Holdstock, 2002). This systematic review of experimental paradigms assessing the effects of the dose of alcohol on various behavioral risk taking tasks suggest that higher alcohol doses (0.6 g/kg and above) produces the most robust increase in behavioral risk taking across tasks, compared to lower doses of alcohol (<0.6 g/kg). Results suggest the BART is the most sensitive behavioral risk task used to detect increases in risk taking in moderate/higher doses compared to lower doses of alcohol. This review also highlights the difficulty in measuring behavioral risk taking, as behavioral risk taking is a complex, multifaceted phenomenon that may involve multiple constructs and means to capture it. Future research is needed to standardize experimental administration protocols, to aid in advancing the field of alcohol administration experiments, and to determine the most accurate measurement of behavioral risk taking. PUBLIC HEALTH SIGNIFICANCE: Past experimental paradigms measuring behavioral risk taking under the influence of alcohol in emerging adults have used various alcohol administration paradigms, experimental protocols, and behavioral risk tasks. Key to examining behavioral risk taking via experimental paradigms should use at higher alcohol doses. Future interventions need to assess for levels of blood alcohol concentration when assessing for at-risk populations for alchol use disorders.

Deter the emotions: Alexithymia, impulsivity and their relationship to binge drinking

Introduction

The relevance of both emotion processing and impulsivity to alcohol use and misuse is increasingly recognised, yet there is a scarcity of studies addressing their reciprocal interaction. The present study aimed to examine the role that difficulties in emotion processing and trait impulsivity play in explaining binge drinking pattern of alcohol use in student population. We looked at binge drinking, as it is a risk factor to later alcohol abuse and is a common alcohol drinking habit among students. Alexithymia (from Greek as "deter/repel emotions"), a difficulty in identifying and describing feelings in self and others is increasingly recognised as a feature of alcohol misuse.

Methods

One-hundred and seventy-four student alcohol drinkers were assessed for their drinking habits (Alcohol Use Questionnaire), as well as for alexithymia (Toronto Alexithymia Scale) and impulsivity trait (Barratt Impulsiveness Scale); facial emotional expression judgements were also tested.

Results

A direct relationships between, both, alexithymia and impulsivity, and binge drinking was found. When combined, trait impulsivity partially mediated the relationship between alexithymia and binge drinking. Facial emotional expression judgements also showed a relationship with binge drinking.

Conclusions

These findings highlight the importance of both emotion processing and impulsivity in understanding binge drinking and indicate potential routes for prevention and intervention techniques, especially towards those who may be at risk of later alcohol abuse.

The Development of Impulsivity and Sensation Seeking: Associations with Substance Use among At-Risk Adolescents

We investigated if the dual systems model could explain the increased rates of substance use among at-risk youth. This study sampled 365 adolescents, 289 of which had a family history of substance use disorder, assessed biannually between the ages 13-16 years old. Growth curve analyses revealed that higher levels of impulsivity were related to higher levels of sensation seeking and a slower rate of decline in impulsivity was related to a faster rate of increase in sensation seeking. Only family history status and sensation seeking were directly associated with substance use (marijuana, alcohol) at age 16, though family history status was also indirectly related to substance use through higher levels of impulsivity to higher levels of sensation seeking.

Network failures: When incentives trigger impulsive responses

Adequate control of impulsive urges to act is demanded in everyday life but is impaired in neuropsychiatric conditions such as stimulant use disorder. Despite intensive research it remains unclear whether failures in impulse control are caused by impaired suppression of behavior or by the over invigoration of behavior by stimuli associated with salient incentives such as drugs, food, and money. We investigated failures in impulse control using functional magnetic resonance imaging (fMRI) to map the neural correlates of premature (impulsive) responses during the anticipation phase of the Monetary Incentive Delay (MID) task in healthy controls (HC), stimulant-dependent individuals (SDIs), and their unaffected first-degree siblings (SIB). We combined task-based fMRI analyses with dynamic causal modeling to show that failures of impulse control were associated with interactions between cingulo-opercular and dorsal striatal networks regardless of group status and incentive type. We further report that group-specific incentive salience plays a critical role in modulating impulsivity in SDIs since drug-related incentives specifically increased premature responding and shifted task modulation away from the dorsal striatal network to the cingulo-opercular network. Our findings thus indicate that impulsive actions are elicited by salient personally-relevant incentive stimuli and those such slips of action recruit a distinct fronto-striatal network.

Are hazardous drinkers more impulsive than light drinkers? A comprehensive assessment in young adults

Those with alcohol dependence are characteristically impulsive. It is unclear whether the same is true of hazardous drinkers (i.e., women routinely drinking more than 14 units in a typical week but fewer than 35, and men drinking more than 14 units but fewer than 50). Yet, it is important to understand the mechanisms involved in such drinking, since it places the drinker at risk for future harm. The present study thus comprehensively assessed whether impulsivity was elevated in hazardous drinkers, compared to lighter drinkers. An opportunity sample of 57 light and 49 hazardous drinkers was assessed on the following impulsivity subdomains (via the measures in parentheses): (i) trait impulsivity (the Barratt Impulsiveness Scale, Version 11); (ii) temporal impulsivity (the Monetary Choice Questionnaire); (iii) stopping impulsivity (the Stop-Signal Task); (iv) waiting impulsivity (the Continuous Performance Task or CPT); (v) reward-sensitivity (the Behavioural Activation Scales); and (vi) risk-taking (the Balloon Analogue Risk Task). Alcohol- and other drug-dependent individuals were excluded from the study, while socio-demographics (age, gender, and socio-economic status), mood, binge drinking, and nicotine intake were all controlled for. The groups were compared via a series of Bonferroni-corrected, independent-measures t tests. The results revealed that hazardous drinkers were more impulsive than light drinkers on the CPT; there were no other statistically significant group differences. Consistent with the above, a logistic regression, with drinking group as the dependent variable and the impulsivity indices as independent variables, revealed that only CPT performance was a significant predictor of drinking status. Other than gender, none of the control variables significantly correlated with CPT performance. A sequential linear regression revealed that drinking status continued to predict CPT performance, after first accounting for gender. Thus, from a battery of impulsivity measures, only waiting impulsivity (i.e., CPT score) was elevated in hazardous drinkers, relative to lighter drinkers. Waiting impulsivity may thus be important in the maintenance of hazardous drinking.

Ethanol induces maladaptive impulse control and decreased seeking behaviors in mice

Waiting impulsivity is a risk factor for many psychiatric disorders including alcohol use disorder (AUD). Highly impulsive individuals are vulnerable to alcohol abuse. However, it is not well understood whether chronic alcohol use increases the propensity for impulsive behavior. Here, we establish a novel experimental paradigm demonstrating that continuous binge-like ethanol exposure progressively leads to maladaptive impulsive behavior. To test waiting impulsivity, we employed the 5-choice serial reaction time task (5-CSRTT) in C57BL/6J male mice. We assessed premature responses in the fixed and variable intertrial interval (ITI) 5-CSRTT sessions. We further characterized our ethanol-induced impulsive mice using Open Field, y-maze, two-bottle choice, and an action-outcome task. Our results indicate that continuous binge-like ethanol exposure significantly increased premature responses when mice were tested in variable ITI sessions even during a prolonged abstinent period. Ethanol-induced impulsive mice exhibited anxiety-like behavior during chronic exposures. This behavior was also observed in a separate cohort that was subjected to 20 days of abstinence. Ethanol-treated mice were less motivated for a sucrose reward compared with air-exposed control mice, while also demonstrating reduced responding during action-outcome testing. Overall, ethanol-treated mice demonstrated increased impulsive behavior, but a reduced motivation for a sucrose reward. Although waiting impulsivity has been hypothesized to be a trait or risk factor for AUD, our findings indicate that maladaptive impulse control can also be potentiated or induced by continuous chronic ethanol exposure in mice.

Impulsivity is a heritable trait in rodents and associated with a novel quantitative trait locus on chromosome 1

Impulsivity describes the tendency to act prematurely without appropriate foresight and is symptomatic of a number of neuropsychiatric disorders. Although a number of genes for impulsivity have been identified, no study to date has carried out an unbiased, genome-wide approach to identify genetic markers associated with impulsivity in experimental animals. Herein we report a linkage study of a six-generational pedigree of adult rats phenotyped for one dimension of impulsivity, namely premature responding on the five-choice serial reaction time task, combined with genome wide sequencing and transcriptome analysis to identify candidate genes associated with the expression of the impulsivity trait. Premature responding was found to be heritable (h² = 13-16%), with significant linkage (LOD 5.2) identified on chromosome 1. Fine mapping of this locus identified a number of polymorphic candidate genes, however only one, beta haemoglobin, was differentially expressed in both the founder strain and F6 generation. These findings provide novel insights into the genetic substrates and putative neurobiological mechanisms of impulsivity with broader translational relevance for impulsivity-related disorders in humans.

Neural circuitry and mechanisms of waiting impulsivity: relevance to addiction

Impatience-the failure to wait or tolerate delayed rewards (e.g. food, drug and monetary incentives)-is a common behavioural tendency in humans. However, when rigidly and rapidly expressed with limited regard for future, often negative consequences, impatient or impulsive actions underlie and confer susceptibility for such diverse brain disorders as drug addiction, attention-deficit hyperactivity disorder (ADHD) and major depressive disorder. Consequently, 'waiting' impulsivity has emerged as a candidate endophenotype to inform translational research on underlying neurobiological mechanisms and biomarker discovery for many of the so-called impulse-control disorders. Indeed, as reviewed in this article, this research enterprise has revealed a number of unexpected targets and mechanisms for intervention. However, in the context of drug addiction, impulsive decisions that maximize short-term gains (e.g. acute drug consumption) over longer-term punishment (e.g. unemployment, homelessness, personal harm) defines one aspect of impulsivity, which may or may not be related to rapid, unrestrained actions over shorter timescales. We discuss the relevance of this distinction in impulsivity subtypes for drug addiction with reference to translational research in humans and other animals. This article is part of the theme issue 'Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications'.

The Role of Impulsivity Facets on the Incidence and Development of Alcohol Use Disorders

Alcohol Use Disorder (AUD) is a chronic relapsing disorder defined according to the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5; American Psychiatric Association 2013), "by a cluster of behavioural and physical symptoms, which can include, withdrawal, tolerance and craving". Social, emotional, behavioural and cognitive factors are important contributors to AUD. Impulsivity, a multifaceted behavioural concept, defined as a predisposition for rapid and unplanned actions, without considering potential negative consequences of these actions, represents an important such factor. In this chapter, research on the role of distinct impulsivity dimensions in different severity stages of alcohol use is presented.Increased self-reported (trait) impulsivity and an inability to wait, as well as difficulty to adjust behaviour appropriately following a failure to withhold a response are observed across the spectrum of alcohol-use severities. Research on temporal impulsivity (inability to delay gratification) consistently shows deficits in more severe alcohol users. Data on temporal impulsivity in early stages of alcohol use are less consistent, with some studies showing no differences between high and moderate drinkers, while others indicating increased impulsivity in high alcohol users. Data on reflexion impulsivity are currently limited to draw conclusions. Recent research is also presented suggesting the importance of perception and interpretation of physiological and emotional signals on alcohol use behaviour highlighting the necessity of comprehensive integration of the field of the study of emotion and interoception with impulsivity research.

Intoxicated aggression: Do alcohol and stimulants cause dose-related aggression? A review

RATIONALE

Violence and drug use are significant public health challenges that are strongly linked. It is known that alcohol plays a major role in the causation of unnatural deaths and that stimulants like cocaine and amphetamine are often implicated in aggressive acts or violence. However, a clear causal relationship between these substances and aggression, and more specifically a blood concentration threshold at which intoxicated aggression emerges is lacking. In case of a crime and subsequent law enforcement, knowledge about dose-response relationships could be of pivotal importance when evaluating the role of alcohol and drugs in aggressive offences.

AIMS

The present review aimed to determine whether there is a causal relation between intoxication with these psychoactive substances and aggression, and to define blood concentration thresholds above which these substances elicit aggression.

METHODS

Empirical articles published between 2013 and 2017 and review papers containing the predefined search strings were identified through searches in the PubMed and Embase databases and additional reference list searches. The complete search query yielded 1578 publications. Initially all articles were manually screened by title and abstract. Articles with irrelevant titles, given the selected search terms and review aims were discarded. Remaining articles were carefully studied and those that did not comply with the main objectives of this review were discarded. At the end of this process, 167 titles were found eligible for review.

FINDINGS AND CONCLUSION

While placebo-controlled experimental studies clearly showed a causal link between alcohol and aggression, it is evident that such a link has not yet been established for cocaine and amphetamines. In case of alcohol, it is clear that there are various individual and contextual factors that may contribute to the occurrence of an aggressive act during intoxication. A clear threshold blood alcohol concentration has not been defined yet for alcohol, but a statistically significant increase of aggression has been demonstrated at a dose of 0.75 g/kg and higher. Future studies into intoxicated aggression should include multiple doses of alcohol and stimulants and take into account individual and contextual factors.

Method effects of the relation between family history of alcoholism and parent reports of offspring impulsive behavior

There is an extensive, albeit inconsistent, literature on the relation between parental alcoholism and offspring impulsive behavior. The reasons for this inconsistency are likely multiple but it seems probable that method effects due to different methodological approaches might explain some of the inconsistencies. Offspring behavior is typically assessed based on informant reports. However, no specific method has been demonstrated as optimal for analyzing informant reports, and conclusions may differ depending on the method used. The present study compared findings derived from a multi-informant method proposed by Bauer et al. (2013) to other structural equation models. Participants came from Wave 7 of the Alcohol, Health and Behavior study and included mother and father reports of offspring impulsive behavior on the Health and Behavior Questionnaire (Armstrong, Goldstein, & the MacArthur Working Group on Outcome Assessment, 2003). There were 368 offspring (50% female, age range 3-17 years, meanage = 6.78, SDage = 3.07) from 205 families. The multi-informant model and the single-reporter models each provided a good fit of the data; however, findings differed based on the approach employed. Specifically, the mother-only report model found that offspring with a family history of alcoholism (FHA) were more impulsive compared to offspring without a FHA; no effect of FHA was found in the other single-reporter models. Ratings of offspring impulsive behavior were higher on the father perspective factor suggesting alcoholic fathers were biased in their reports. These findings highlight the relation between FHA and impulsive behavior varies depending on the analytic method used.

Facets of impulsivity and alcohol use: What role do emotions play?

Alcohol misuse is a major public concern. Impulsivity has been recognised as a significant risk factor predisposing for the initiation of alcohol use, continuation and excessive alcohol use. Evidence suggests that impulsivity is also a result of both acute alcohol intoxication and long-term alcohol abuse. The multifaceted character of impulsivity and the various ways of assessing it in humans and animal models, hampers the full understanding of how impulsivity relates to alcohol use and misuse. Therefore, in this review we evaluate recent developments in the field, trying to disentangle the contribution of different impulsivity subtypes as causes and effects of alcohol use. Moreover, we review a growing body of evidence, including brain imaging, suggesting the importance of emotional states in engaging in alcohol consumption, particularly in highly impulsive individuals. We also present recent insights into how emotional processing is manifested in alcoholism and binge drinking and suggest novel approaches to treatment and prevention opportunities which target emotional-regulation as well as emotional perception and insight.

Alcohol affects the P3 component of an adaptive stop signal task ERP

BACKGROUND

The P3 component of the event-related potential (ERP) has been particularly useful in alcohol research for identifying endophenotypes of alcohol-use disorder (AUD) risk in sober subjects. However, practice and/or fatigue reduce P3 amplitude, limiting the ability to ascertain acute and adaptive effects of alcohol exposure. Here, we report acute alcohol effects on P3 amplitude and latency using an adaptive stop signal task (aSST).

METHODS

One hundred forty-eight non-dependent moderate to heavy social drinkers, ages 21 to 27, participated in two single-blind, alcohol or placebo, counterbalanced sessions approximately 1 week apart. During each session, subjects performed an adaptive stop signal task (aSST) at 1) baseline, 2) upon reaching the target 60 mg/dL breath alcohol concentration or at the equivalent time during the placebo session, and 3) approximately 135 min later while the breath alcohol concentration was clamped. Here, we report on differences between baseline and first subsequent measurements across the experimental sessions. During each aSST run, the stop signal delay (SSD, the time between stop and go signals) adjusted trial-by-trial, based on the subject's performance.

RESULTS

The aSST reliably generated a STOP P3 component that did not change significantly with repeated task performance. The pre-infusion SSD distribution was bimodal, with mean values several hundred msec apart (FAST: 153 msec and SLOW: 390 msec). This suggested different response strategies: FAST SSD favoring "going" over "stopping", and SLOW SSD favoring "stopping" over "going". Exposure to alcohol at 60 mg/dL differentially affected the amplitude and latency of the STOP P3 according to SSD group. Alcohol significantly reduced P3 amplitude in the SLOW SSD compared to the FAST SSD group, but significantly increased P3 latency in the FAST SSD compared to the SLOW SSD group.

CONCLUSIONS

The aSST is a robust and sensitive task for detecting alcohol-induced changes in inhibition behavior as measured by the P3 component in a within-subject design. Alcohol was associated with P3 component changes, which varied by SSD group, suggesting a differential effect as a function of task strategy. Overall, the data support the potential utility of the aSST in the detection of alcohol response-related AUD risk.

The association between impulsivity, emotion regulation, and symptoms of alcohol use disorder

Emotion dysregulation and impulsivity are important factors influencing the development and course of alcohol dependence. However, few empirical studies investigate the association between different aspects of impulsivity (cognitive, attentional, behavioral), emotion regulation, and alcohol use disorder symptoms in the same model. The goal of this study was to assess the association between emotion regulation and different facets of impulsivity among patients with an alcohol use disorder and healthy controls. The sample was comprised of 273 individuals: 180 participants with an alcohol use disorder undergoing inpatient alcohol treatment and 93 healthy controls. Emotion regulation was assessed using the Schutte Self-Report Emotional Intelligence Test subscale. Impulsivity was assessed with Barratt's Impulsiveness Scale (BIS-11). Statistical models tested both the BIS-11 total score, as well as three secondary factors (non-planning, attentional, and motor impulsivity). Findings indicate that individuals with alcohol use disorder symptoms were characterized by poor emotion regulation and high levels of impulsivity in all analyzed domains. Moreover, path analytic models indicated that after accounting for demographic factors (i.e., biological sex, age, education) there was evidence for a significant indirect effect of alcohol use disorder symptomatology on non-planning and attentional impulsivity via emotion regulation. There was no association between emotion regulation and motor impulsivity. These findings indicate the importance of targeting emotion regulation skills as well as behavioral control when treating patients with alcohol use disorder.

Cognitive and behavioural dispositions in offspring at high risk for alcoholism

OBJECTIVES

Offspring with family history of alcoholism are considered to be at high risk for alcoholism. The present study sought to expand our understanding of cognitive and behavioural dispositions associated with executive control and self-regulation in alcohol naïve offspring with and without family history of alcoholism.

METHODS

Sample comprised of alcohol naive offspring in two groups: (i) at high risk (n = 34) and (ii) at low risk for alcoholism (n = 34). Both groups were matched on age (+/-1 year), education (+/-1 year) and gender. Measures used were: Mini-International Neuropsychiatric Interview, Family Interview for Genetic Studies, Socio-demographic Data Sheet, Annett's Handedness Questionnaire, Barratt's Impulsiveness Scale-version 11, Digit Span Test, Spatial Span Test, Tower of London, Wisconsin Card Sorting Test, Iowa Gambling Task (IGT) and Game of Dice Task (GDT).

RESULTS

Results showed that alcohol naive offspring at high risk for alcoholism reported significantly high impulsivity and demonstrated significant differences on executive functions and decision making tasks. Correlation analysis revealed that high impulsivity was significantly associated with poor performance on explicit decision making task (GDT) and executive function task (WCST). There was no significant correlation between two decision making tasks (IGT and GDT) in both groups and performance on IGT was not significantly associated with impulsivity and executive functions.

CONCLUSIONS

The present study indicates cognitive and behavioural dispositions in alcohol naive offspring at high risk for alcoholism and support the sub-optimal balance between reflective and impulsive system responsible for addiction. Furthermore, present study supports separability between two different types of decision making tasks.

Psychosocial and neural indicators of resilience among youth with a family history of substance use disorder

BACKGROUND

Little is known regarding the combined influence of psychosocial and neural protective mechanisms against substance use. The present study examined the extent to which neuroimaging measures of disinhibition predicted resilience against binge drinking and marijuana use among youth with a family history of substance use disorder (SUD; FH+), accounting for psychosocial measures of behavioral control.

METHODS

Participants were 57 FH+ youth from the Michigan Longitudinal Study categorized into resilient and high-risk groups based on patterns of weekly binge drinking and monthly marijuana use during early adulthood. Psychosocial measures of behavioral control (reactive control and externalizing behavior during early and late adolescence) and neural measures of disinhibition (Go/No-Go task and Monetary Incentive Delay Task (MIDT) measured through functional magnetic resonance imaging (fMRI)) were entered sequentially in hierarchical logistic regression models to predict resilient versus high-risk groups.

RESULTS

Greater activation in the right dorsolateral prefrontal cortex (DLPFC) during correctly inhibited trials on the Go/No-Go task was a significant predictor of resilience (OR = 2.46, p < 0.05), over and above greater reactive control in early adolescence (OR = 4.96, p < 0.05) and lower externalizing behavior in late adolescence (OR = 0.64, p < 0.05). Neural activation in the ventral striatum associated with reward anticipation during the MIDT was not a significant predictor of resilience.

CONCLUSIONS

Brain function in the right DLPFC associated with inhibitory control may be a neural indicator of resilience against elevated substance use among FH+ youth, even after accounting for psychosocial measures of behavioral control.

The association between parental history and delay discounting among individuals in recovery from addiction

BACKGROUND

Family history of addiction is a risk factor for substance use disorders. Delay discounting (DD) is associated with the risk of substance use and dependence, and is predictive of the likelihood of successful abstinence and treatment outcomes; thus, we investigated the extent to which having parents with addiction (parental history of addiction) and number of addicted parents affect DD among individuals in recovery from addiction.

METHODS

Data from 177 individuals in recovery from addiction from The International Quit and Recovery Registry (IQRR), an ongoing online data collection program that aims to understand addiction and how people succeed in recovery, were included in the analysis. Participants with no, one, or two parents with addiction were compared on measures of DD using an adjusting-amount task.

RESULTS

Parental history of addiction was significantly associated with delay discounting. After controlling for age and gender, which were significantly different between groups, participants reporting two biological parents with addiction had significantly higher DD rates compared to those reporting one or no parents with addiction.

CONCLUSIONS

Participants with two parents with addiction had significantly higher rates of discounting compared to those with no or only one parent with addiction. This information can serve as a foundation to better identify and target important subgroups that need additional or non-traditional intervention strategies to address their larger degree of impulsivity and help maintain abstinence or achieve better treatment outcomes.

Sex differences in the interacting roles of impulsivity and positive alcohol expectancy in problem drinking: A structural brain imaging study

Alcohol expectancy and impulsivity are implicated in alcohol misuse. However, how these two risk factors interact to determine problem drinking and whether men and women differ in these risk processes remain unclear. In 158 social drinkers (86 women) assessed for Alcohol Use Disorder Identification Test (AUDIT), positive alcohol expectancy, and Barratt impulsivity, we examined sex differences in these risk processes. Further, with structural brain imaging, we examined the neural bases underlying the relationship between these risk factors and problem drinking. The results of general linear modeling showed that alcohol expectancy best predicted problem drinking in women, whereas in men as well as in the combined group alcohol expectancy and impulsivity interacted to best predict problem drinking. Alcohol expectancy was associated with decreased gray matter volume (GMV) of the right posterior insula in women and the interaction of alcohol expectancy and impulsivity was associated with decreased GMV of the left thalamus in women and men combined and in men alone, albeit less significantly. These risk factors mediated the correlation between GMV and problem drinking. Conversely, models where GMV resulted from problem drinking were not supported. These new findings reveal distinct psychological factors that dispose men and women to problem drinking. Although mediation analyses did not determine a causal link, GMV reduction in the insula and thalamus may represent neural phenotype of these risk processes rather than the consequence of alcohol consumption in non-dependent social drinkers. The results add to the alcohol imaging literature which has largely focused on dependent individuals and help elucidate alterations in brain structures that may contribute to the transition from social to habitual drinking.

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Alcohol expectancy (AE) and impulsivity are risk factors for problem drinking.

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AE mediates the correlation between right insula GMV and problem drinking in women.

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AE and impulsivity interacts to mediate left thalamus GMV and problem drinking in all.

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Models where changes in GMV as a result of problem drinking are not supported.

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.