Lack of tolerance to the disinhibiting effects of alcohol in heavy drinkers

Meta-analysis of acute alcohol effects on response inhibition

Alcohol intoxication impairs response inhibition; however, discrepant findings have been reported regarding the magnitude and moderators of this effect. This meta-analysis of human laboratory studies aimed to quantify acute effects of alcohol on response inhibition and evaluate moderators of this effect. Eligible studies examined alcohol's effects on response inhibition with the Go/No-Go (GNG) task (n = 1616 participants) or Stop Signal Task (SST) (n = 1310 participants). Results revealed a detrimental effect of acute alcohol on response inhibition overall (g = 0.411, 95 % CI [0.350, 0.471]), with similar effects in studies using GNG (g = 0.431, SE = 0.031) and SST (g = 0.366, SE = 0.063). Effect sizes were larger in studies involving higher breath alcohol concentration levels and under GNG conditions that established a prepotent response set. These findings establish the magnitude, precision, and potential moderators of alcohol's effects on inhibitory control, furthering understanding of a key neurobehavioral mechanism proposed to underlie alcohol-related impulsivity and impaired control over consumption.

Haven't lost the positive feeling: a dose-response, oral alcohol challenge study in drinkers with alcohol use disorder

Models of addiction are based on neurobiological, behavioral, and pharmacological studies in animals, but translational support from human studies is limited. Studies are lacking in examining acute responses to alcohol in drinkers with alcohol use disorder (AUD), particularly in terms of relevant intoxicating doses and measurement of stimulating and rewarding effects throughout the breath alcohol concentration (BrAC) time curve. Participants were N = 60 AUD drinkers enrolled in the Chicago Social Drinking Project and examined in three random-order and blinded sessions for subjective and physiological responses to a beverage containing 0.0 g/kg, 0.8 g/kg, and 1.2 g/kg alcohol. BrAC in the alcohol sessions at 60 min was 0.09 g/dL and 0.13 g/dL, respectively. Both doses of alcohol produced significant biphasic effects on subjective measures of stimulation, euphoria, reward (liking and wanting), sedation, and neuroendocrine and cardiovascular factors. Increased pleasurable effects of alcohol were pronounced during the rising limb-to-peak BrAC and sedating effects emerged during the declining limb. Alcohol dose-dependently increased feel drug ratings and rewarding effects at peak BrAC or early declining limb, and physiological responses at the rising limb. Thus, rather than the notion of an overall tolerance, results show an alcohol response phenotype characterized by sensitivity to alcohol's stimulating, rewarding and physiological effects. The results of this study may aid in the conceptualization of alcohol addiction as a disorder characterized by the persistence of enhanced hedonic alcohol responses rather than chronic tolerance and reward deficiency.

Anti-saccade as a Tool to Evaluate Neurocognitive Impairment in Alcohol Use Disorder

It has been widely shown that chronic alcohol use leads to cognitive dysfunctions, especially inhibitory control. In an extension of the traditional approach, this research field has benefited from the emergence of innovative measures, among which is an anti-saccade, allowing direct and sensitive measure of the eye movements indexing attention bias to alcohol-related cues and the capability of inhibiting the reflexive saccades to the cues. During the past decade, there are numerous reports showing that drinkers make more unwanted reflexive saccades and longer latency in the anti-saccade task. These increased errors are usually explained by the deficits in inhibitory control. It has been demonstrated that inhibitory control on eye movement may be one of the earliest biomarkers of the onset of alcohol-related cognitive impairments. This review summarizes how an anti-saccade task can be used as a tool to investigate and assess the cognitive dysfunctions and the early detection of relapsing risk of alcohol dependence.

Contrast sensitivity and retinal straylight after alcohol consumption: effects on driving performance

In this study, we aimed to investigate the effects of alcohol intake on visual function and driving performance, as well as on the relationship between these. A total of 40 healthy participants took part in three experimental sessions: one baseline session and two further sessions after consuming two different quantities of alcohol (300 ml and 450 ml of red wine). The breath alcohol content (BrAC) was measured using a breath analyzer. The contrast sensitivity and retinal straylight due to the forward intraocular scattering were measured to characterize visual function, and driving performance was assessed in three different scenarios using a driving simulator. The results showed a deterioration in contrast sensitivity and retinal straylight after drinking alcohol, in addition to an impaired ability to drive, especially for the highest alcohol intake. We also observed that the deteriorated driving performance was a function of the contrast sensitivity and retinal straylight under the effects of alcohol, indicating that these visual variables can partially predict driving performance in these conditions.

DUI offenders display reduced perception of intoxication and heightened impulsive choice in response to alcohol

Driving under the influence (DUI) of alcohol continues to be a major contributor in traffic fatalities. There is growing evidence for heightened trait impulsivity in DUI offenders, but little is known about how impulsivity could interact with alcohol intoxication in a manner that would increase the likelihood of driving while intoxicated. This placebo-controlled study examined the acute effects of 0.65g/kg alcohol on 2 facets of impulsivity (impulsive choice and response inhibition), simulated risky driving behavior, and subjective intoxication in a group of 20 DUI offenders and 20 control drivers with no history of DUI. It was predicted that compared with controls, DUI offenders would self-report greater impulsivity, and display greater impulsive choice and driver risk taking, particularly in response to alcohol. Results showed that alcohol impaired drivers' inhibitory control and increased their impulsive choice behavior and risky driving behavior. Alcohol selectively increased impulsive choice of DUI offenders, as control drivers showed no alcohol-induced increase in their impulsive choices. Results also showed that, compared with controls, offenders reported feeling less intoxicated and were more willing to drive after drinking. Laboratory studies are beginning to show that DUI offenders differ from nonoffenders in their acute responses to alcohol. This study identified two alcohol response characteristics of DUI offenders that indicate their lack of risk awareness during intoxication: heightened impulsivity and reduced subjective intoxication. Strategies and treatments to alter these response characteristics in DUI offenders could enhance their risk awareness during the intoxicated state and possibly reduce risk of DUI recidivism. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Alcohol effects on response inhibition: Variability across tasks and individuals

Considerable research has investigated the acute effects of alcohol on response inhibition, but a number of issues remain unresolved. Given that most studies use only a single laboratory task to assess inhibition, it is often difficult to determine whether alcohol's effects are task specific or generalize across measures of the same construct. Moreover, relatively few studies have directly compared effects of alcohol under ascending and descending blood alcohol concentrations (BACs), and those that have often failed to disentangle BAC limb effects from the effects of repeated testing. This study was intended to provide a test of alcohol's effects on behavioral inhibition using multiple laboratory measures in a relatively large sample and comparing effects under ascending and descending BAC. Young adults (N = 216) completed three commonly used inhibition tasks (Stroop, antisaccade, and stop-signal) at baseline and again 1-3 weeks later under one of three beverage conditions (alcohol, placebo or control) and one of two BAC limb conditions (ascending/descending or descending only). Findings indicated considerable specificity in alcohol's effects. Relative to control and placebo conditions, antisaccade performance suffered under both ascending and descending BAC and stop-signal reaction time (RT) suffered only under descending BAC. The Stroop RT interference effect was not affected by alcohol, though alcohol did impair response accuracy on incongruent Stroop trials. Baseline performance moderated effects of alcohol on both antisaccade accuracy and Stroop interference, suggesting the importance of individual differences. The current findings suggest that more specificity is required in characterizing acute effects of alcohol on inhibitory control. (PsycINFO Database Record

Alcohol-Induced Impairment of Balance is Antagonized by Energy Drinks

BACKGROUND

The acute administration of alcohol reliably impairs balance and motor coordination. While it is common for consumers to ingest alcohol with other stimulant drugs (e.g., caffeine, nicotine), little is known whether prototypical alcohol-induced balance impairments are altered by stimulant drugs. The purpose of this study was to examine whether the coadministration of a high-caffeine energy drink with alcohol can antagonize expected alcohol-induced increases in body sway.

METHODS

Sixteen social drinkers (of equal gender) participated in 4 separate double-blind dose administration sessions that involved consumption of alcohol and energy drinks, alone and in combination. Following dose administration, participants completed automated assessments of balance stability (both eyes open and eyes closed) measured using the Biosway Portable Balance System. Participants completed several subjective measures including self-reported ratings of sedation, stimulation, fatigue, and impairment. Blood pressure and pulse rate were recorded repeatedly.

RESULTS

The acute administration of alcohol increased body sway, and the coadministration of energy drinks antagonized this impairment. When participants closed their eyes, alcohol-induced body sway was similar whether or not energy drinks were ingested. While alcohol administration increased ratings of sedation and fatigue, energy drink administration increased ratings of stimulation and reduced ratings of fatigue. Modest increases in systolic and diastolic blood pressure following energy drink administration were also observed.

CONCLUSIONS

Visual assessment of balance impairment is frequently used to indicate that an individual has consumed too much alcohol (e.g., as part of police-standardized field sobriety testing or by a bartender assessing when someone should no longer be served more alcohol). The current findings suggest that energy drinks can antagonize alcohol-induced increases in body sway, indicating that future work is needed to determine whether this observation regarding neuromotor functioning applies to alcohol in combination with all types of stimulant drugs.

Alcohol-induced performance impairment: a 5-year re-examination study in heavy and light drinkers

BACKGROUND

The theory of behavioral tolerance to alcohol posits that greater experience with drinking to intoxication leads to less impaired cognitive and psychomotor performance. However, the degree to which behavioral tolerance develops or changes over time in adults due to repeated heavy alcohol drinking has not been clearly demonstrated.

METHOD

We examined data from the first 6 years of the Chicago Social Drinking Project to test whether chronic heavy drinkers (HDs; n = 86) and light drinkers (LDs; n = 69) exhibit behavioral tolerance or changes in perceived impairment at two testing phases in early adulthood. Tasks were the Grooved Pegboard and Digit Symbol Substitution Test (DSST) given at initial testing and then repeated in a re-examination phase 5 years later. Alcohol (0.8 g/kg) and placebo were administered at separate sessions in each phase for a total of 620 individual laboratory sessions.

RESULTS

HDs exhibited less impairment over time on the Pegboard task but not on the DSST, while LDs did not exhibit behavioral tolerance on either task. HDs reported persistently lower perceived impairment compared to LDs.

CONCLUSIONS

These findings demonstrate that behavioral tolerance in HDs is evident over time on rote fine motor skills (Pegboard) but not more complex skills integrating motor speed, encoding, and short-term memory (DSST). The results have implications for our understanding of alcohol-induced impairments across neurobehavioral processes in heavy drinkers and their ongoing risks for alcohol-related consequences over time.

The sensitivity of laboratory tests assessing driving related skills to dose-related impairment of alcohol: A literature review

Laboratory tests assessing driving related skills can be useful as initial screening tools to assess potential drug induced impairment as part of a standardized behavioural assessment. Unfortunately, consensus about which laboratory tests should be included to reliably assess drug induced impairment has not yet been reached. The aim of the present review was to evaluate the sensitivity of laboratory tests to the dose dependent effects of alcohol, as a benchmark, on performance parameters. In total, 179 experimental studies were included. Results show that a cued go/no-go task and a divided attention test with primary tracking and secondary visual search were consistently sensitive to the impairing effects at medium and high blood alcohol concentrations. Driving performance assessed in a simulator was less sensitive to the effects of alcohol as compared to naturalistic, on-the-road driving. In conclusion, replicating results of several potentially useful tests and their predictive validity of actual driving impairment should deserve further research. In addition, driving simulators should be validated and compared head to head to naturalistic driving in order to increase construct validity.

Searching for Mr. Hyde: A Five-Factor Approach to Characterizing "Types of Drunks"

Some individuals "change" more dramatically than others when intoxicated, and the nature and magnitude of these changes can result in harmful outcomes. This study utilized reports (N¼374) of participants' "typical" five-factor model (FFM) characteristics across sober and intoxicated states and assessed the degree to which these reports could be grouped into meaningful clusters, as well as the association of cluster membership with negative alcoholrelated consequences. Results from finite mixture model clustering revealed a four cluster solution. Cluster 1, "Hemingway," was the largest and defined by intoxication-related decreases in Conscientiousness and Intellect that were below average; Cluster 2, "Mary Poppins," was defined by being high in Agreeableness when sober, decreasing less than average in Conscientiousness and Intellect and increasing more than average in Extraversion when drunk; Cluster 3, "Mr. Hyde," reported larger drunk decreases in Conscientiousness and Intellect and smaller increases in Extraversion; Cluster 4, "The Nutty Professor," was defined by being low in Extraversion when sober, increasing more than average in Extraversion and decreasing less than average in Conscientiousness when drunk. Cluster membership was associated with experiencing more alcohol consequences. These results support use of the FFM to characterize clinically meaningful subgroups of sober-to-drunk differences in trait expression.

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.

Protracted impairment of impulse control under an acute dose of alcohol: a time-course analysis

Alcohol is well-known for impairing impulse control as well as its disruptive effects on other aspects of behavioral functioning, such as motor control. Time-course analyses during a single dose show rapid development of acute tolerance to impairment of motor coordination, reaction time, and levels of subjective intoxication, but no acute tolerance to impairment of the ability to inhibit responses. Evidence for a possible lag in tolerance development to the impairing effects of alcohol on inhibitory control suggests that, as drinkers' blood alcohol concentration (BAC) declines, they might exhibit prolonged impulsivity despite having an unimpaired ability to initiate action. The present study extended the time-course analysis to examine the recovery of inhibitory control under a dose of alcohol as drinkers' BAC descended from a peak of 80 mg/100ml to a zero level. Twenty-four healthy adults were tested following 0.65 g/kg alcohol and a placebo in a counterbalanced order. They performed a cued go/no-go task that measured response inhibition. They also performed tasks that assessed reaction time, motor coordination, and completed ratings of their subjective levels of intoxication. Alcohol initially impaired inhibitory control, response time, and motor coordination and increased subjective ratings of intoxication. However, acute tolerance to the impairing effects of alcohol was observed for measures of response time, motor coordination, and ratings of intoxication and these measures returned to sober (i.e., placebo) levels by the time BAC fell to near zero. By contrast, impairment of inhibitory control showed no acute tolerance and remained impaired even when drinkers' BAC returned to near zero. Taken together, these results indicate that the disinhibiting effects of alcohol are present even when the impairing effects of alcohol on other aspects of behavior have diminished under the dose. These findings could provide a greater understanding of impulsive behaviors during the descending limb of intoxication.

Drunk personality: reports from drinkers and knowledgeable informants

Existing literature supports the five-factor model (FFM) of personality (i.e., Extraversion, Agreeableness, Conscientiousness, Emotional Stability, and Intellect or Openness) as a comprehensive representation of stable aspects of mood, affect, and behavior. This study evaluated the FFM as a framework for both self-perceptions of drunkenness (i.e., individual changes in mood, affect, and behavior associated with one's own intoxication), as well "drinking buddies'" perceptions of their friends' drunkenness (i.e., changes in mood, affect, and behavior associated with friends' intoxication) and the association of reported sober-to-drunk differences with negative alcohol-related consequences. College-student drinkers (N = 374; 187 drinking buddy pairs) reported on their sober and drunk levels of the 5 factors, as well as those of their drinking buddies. Buddies completed parallel assessments for themselves and their friends to ensure rater agreement. All participants completed assessments of harmful alcohol outcomes experienced within the past year. Regardless of reporter, differences between drunken and sober states were found across all 5 factors and agreement between self and informant reports was consistently significant and comparable across sober and drunk conditions. Low levels of drunk Conscientiousness and drunk Emotional Stability were associated with experiencing more alcohol-related consequences, even when controlling for sober factor levels and binge-drinking frequency. Findings support the use of the FFM as a clinically relevant framework for organizing differences in personality expression associated with intoxication and the validity of self-reports of drunk personality.

Can the use of multiple stop signals reduce the disinhibiting effects of alcohol?

BACKGROUND

Research has consistently demonstrated that alcohol impairs the ability to divide attention across 2 or more stimuli. However, under certain circumstances, the presentation of multiple stimuli can actually facilitate performance. The "redundant signal effect" (RSE) refers to the phenomenon by which individuals respond more quickly and accurately when information is presented as redundant, bimodal stimuli (e.g., visually and aurally), rather than as a single stimulus presented to either modality alone. Recent work has shown that reaction time (RT) to redundant signals is hastened under alcohol, ameliorating the slowing effects of the drug. However, no research has examined whether RSE can reduce the impairing effects of alcohol on the ability to inhibit behavior.

METHODS

This study examined whether the impairing effects of alcohol on inhibitory control might be altered by the presentation of redundant inhibitory signals. Inhibitory control was assessed by a go/no-go task which included single and redundant inhibitory signals. Performance was tested following placebo (0.0 g/kg) and alcohol (0.65 g/kg). The effect of redundant activation signals on alcohol impairment of response activation was also measured.

RESULTS

The results showed evidence for RSE on the activation of behavior, but not for inhibitory control. Compared with placebo, alcohol slowed RT and reduced response inhibition. Redundant signals had a robust speeding effect on RT, even following alcohol. By contrast, redundant signals failed to improve inhibitory control following placebo or alcohol.

CONCLUSIONS

These findings have important implications for understanding how drinkers respond to multimodal signals in their everyday environments and highlight the vulnerability of inhibitory control to alcohol's impairing effects.

Article Commentary: Calling for Help? Considering Function and Meaning when Patients Drunk-Dial Psychotherapists

Drunk-dialing is a term documented in both popular culture and academic literatures to describe a behavior in which a person contacts another individual by phone while intoxicated. In our collective clinical experience we have found that clients drunk-dial their clinicians too, particularly while in substance use treatment, and yet there is a noticeable absence of research on the topic to guide clinical decision-making within a process-based understanding of these events. As the parameters within which psychotherapy takes place become increasingly technologized, a literature base to document clients’ idiosyncratic use of technology will become increasingly necessary and useful. We provide a brief review of the existing research on drunk-dialing and conclude with specific questions to guide future research and practice.