A virtual reality platform for the measurement of drinking topography

Contextual and psychosocial factors influencing drug reward in humans: The importance of non-drug reinforcement

The reinforcing efficacy, or behavior-strengthening effect, of a substance is a critical determinant of substance use typically quantified by measuring behavioral allocation to the substance under schedules of reinforcement with escalating response requirements. Although responses on these tasks are often used to indicate stable reinforcing effects or trait-level abuse potential for an individual, task designs often demonstrate within-person variability across varying degrees of a constraint within experimental procedures. As a result, quantifying behavioral allocation is an important way to measure the impact of contextual and psychosocial factors on substance reward. We review studies using laboratory self-administration, behavioral economic purchase tasks, and ambulatory assessments to quantify the impact of various contextual and psychosocial factors on behavioral allocation toward consumption of a substance. We selected these assessment approaches because they cover the translational spectrum from experimental control to ecological relevance, with consistent support across these approaches representing greater confidence in the effect. Conceptually, we organized factors that influence substance value into two broad categories: factors that influence the cost/benefit ratio of the substance (social context, stress and affect, cue exposure), and factors that influence the cost/benefit ratio of an alternative (alternative non-drug reinforcers, alternative drug reinforcers, and opportunity costs). We conclude with an overview of future research directions and considerations for clinical application.

Trait impulsivity moderates rate of alcohol consumption in daily life

INTRODUCTION

Rate of alcohol consumption, the speed with which people drink, has been linked to a range of outcomes, including alcohol use disorder symptoms and increased positive affect. However, minimal work has identified who is most likely to drink at elevated rates. Impulsivity is associated with increased attention to positive reinforcers specifically (e.g., positive affect). We therefore examined whether people higher in trait impulsivity engage in faster consumption during drinking episodes.

METHODS

Participants were current drinkers (N = 113; 54 people with borderline personality disorder [BPD], a disorder that involves elevated impulsivity, and 59 community people) who completed a 21-day ecological momentary assessment (EMA) protocol. Multilevel models of drinking episodes (Nobservations = 3,444) examined whether self-reported trait impulsivity, measured at baseline, was associated with faster rise in estimated blood alcohol concentration (eBAC) at each follow-up period.

RESULTS

All UPPS sub-scales were associated with faster rise in eBAC across a drinking episode. In a multivariate model including all sub-scales as simultaneous predictors, sensation seeking and (lack of) perseverance were independently positively associated with rate of consumption. Additional analyses indicated that greater negative urgency and sensation seeking were associated with faster rises in eBAC in participants with BPD, relative to community comparisons.

CONCLUSION

In a sample that captured a wide spectrum of impulsivity, greater impulsivity was associated with drinking alcohol at a faster rate. People higher in sensation seeking and (lack of) perseverance may be prone to drink at faster rates out of a desire to maximize the hedonic effects of alcohol.

PUBLIC SIGNIFICANCE STATEMENT

This study finds that people who are more impulsive tend to drink alcohol faster, putting them at greater risk for negative consequences. This may explain, in part, why impulsivity is linked to experiencing alcohol-related problems.

Alcohol's Role in Campus Sexual Assault Bystander Behavior: A Systematic Review

Between 50% and 70% of campus sexual assaults (SA) involve alcohol and campuses frequently promote bystander intervention strategies to prevent SA in student party contexts. This systematic review evaluates the measurement and outcomes of quantitative studies on how alcohol affects campus SA bystander outcomes. Using four search strategies and rigorous systematic review methods, we conducted a review of 36 studies. We included studies published after 2,000 conducted with college students in the United States, its territories, and Canada which contained information on alcohol use and SA bystander outcomes (behaviors and upstream proxies). Only a third of included studies measured bystander behavior directly, the majority measured upstream proxies (e.g., intentions, self-efficacy). Most studies considered the influence of victim intoxication on bystander outcomes. No studies assessed the pharmacological or physiological effects of alcohol on bystander outcomes. A single study examined hypothetical bystander responses when intoxicated, one-third examined bystander's typical alcohol use in relation to bystander outcomes. Many findings are contradictory, including fundamental details such as how often students encounter SA involving alcohol or whether bystanders' alcohol use predicts outcomes. Findings suggest that students are less likely help intoxicated victims compared to sober victims, but there are clear moderating factors. Perpetrator intoxication was not studied in relation to bystander behavior and did not influence any upstream proxies. Evaluations of interventions on alcohol and bystander topics are promising yet more research is required. This review illuminates key gaps in the literature, including the need for validated measures and scenarios, event-level studies, and alcohol administration trials.

Effect of typical alcohol use and expectancies on the social manipulation of drinking behavior in a virtual bar pilot study

BACKGROUND

Recent work indicates that increasing the drinking rate of a virtual bar-goer (VB) increases the rate of drinking for participants in a virtual reality (VR) bar environment. Here, we test the hypothesis that biopsychosocial factors including typical drinking pattern and expectancy that alcohol enhances social interactions would moderate this effect.

METHODS

We assessed the drinking topography (DT) of participants (N=20) in a VR environment with a programmable VB during two testing sessions: one with a fast-drinking VB (30-60s sip interval) and one in which the VB drank slowly (60-120s sip interval). In this secondary analysis, linear mixed models were used to characterize potential interactions of typical daily alcohol intake (quantity-frequency index [QFI]), maximal alcohol consumed in one bout over the past six months (maxQ), Alcohol Use Disorder Identification Test (AUDIT) score, and expectancy that alcohol enhances social and physical pleasures (SPP) with time in simulation and condition on sip interval and volume.

RESULTS

Individuals with higher MaxQ showed a reduced effect of time on sip volume such that more intense recent binge episodes were associated with consistent drinking. Greater AUDIT scores were associated with lower sip intervals. In addition, greater SPP expectancy was associated with higher sip volumes, but only in the fast-drinking VB condition.

CONCLUSIONS

Greater drinking behavior and social expectancies were associated with more rapid drinking topography. In addition, findings suggest challenging alcohol outcome expectancies related to social enhancement could reduce alcohol-related risks by slowing the rate of alcohol intake in social situations.

Binge and high-intensity drinking-Associations with intravenous alcohol self-administration and underlying risk factors

Some styles of alcohol consumption are riskier than others. How the level and rate of alcohol exposure contribute to the increased risk of alcohol use disorder is unclear, but likely depends on the alcohol concentration time course. We hypothesized that the brain is sensitive to the alcohol concentration rate of change and that people at greater risk would self-administer faster. We developed a novel intravenous alcohol self-administration paradigm to allow participants direct and reproducible control over how quickly their breath alcohol concentration changes. We used drinking intensity and the density of biological family history of alcohol dependence as proxies for risk. Thirty-five alcohol drinking participants aged 21-28 years provided analytical data from a single, intravenous alcohol self-administration session using our computer-assisted alcohol infusion system rate control paradigm. A shorter time to reach 80 mg/dl was associated with increasing multiples of the binge drinking definition (p = 0.004), which was in turn related to higher density of family history of alcoholism (FHD, p = 0.04). Rate-dependent changes in subjective response (intoxication and stimulation) were also associated with FHD (each p = 0.001). Subsequently, given the limited sample size and FHD range, associations between multiples of the binge drinking definition and FHD were replicated and extended in analyses of the Collaborative Study on the Genetics of Alcoholism database. The rate control paradigm models binge and high-intensity drinking in the laboratory and provides a novel way to examine the relationship between the pharmacokinetics and pharmacodynamics of alcohol and potentially the risk for the development of alcohol use disorders.