Effect of setting on the reinforcing and subjective effects of ethanol in social drinkers

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 effective approach for measuring 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.

Social setting interacts with hyper dopamine to boost the stimulant effect of ethanol

Alcohol consumption occurring in a social or solitary setting often yields different behavioural responses in human subjects. For example, social drinking is associated with positive effects while solitary drinking is linked to negative effects. However, the neurobiological mechanism by which the social environment during alcohol intake impacts on behavioural responses remains poorly understood. We investigated whether distinct social environments affect behavioural responses to ethanol and the role of the dopamine system in this phenomenon in the fruit fly Drosophila melanogaster. The wild-type Canton-S (CS) flies showed higher locomotor response when exposed to ethanol in a group setting than a solitary setting, and there was no difference in females and males. Dopamine signalling is crucial for the locomotor stimulating effect of ethanol. When subjected to ethanol exposure alone, the dopamine transport mutant flies fumin (fmn) with hyper dopamine displayed the locomotor response similar to CS. When subjected to ethanol in a group setting, however, the fmn's response to the locomotor stimulating effect was substantially augmented compared with CS, indicating synergistic interaction of dopamine signalling and social setting. To identify the dopamine signalling pathway important for the social effect, we examined the flies defective in individual dopamine receptors and found that the D1 receptor dDA1/Dop1R1 is the major receptor mediating the social effect. Taken together, this study underscores the influence of social context on the neural and behavioural responses to ethanol.

Effects of social housing on alcohol intake in mice depend on the non-social environment

Background

Excessive alcohol consumption leads to serious health problems. Mechanisms regulating the consumption of alcohol are insufficiently understood. Previous preclinical studies suggested that non-social environmental and social environmental complexities can regulate alcohol consumption in opposite directions. However, previous studies did not include all conditions and/or did not include female rodents. Therefore, in this study, we examined the effects of social versus single housing in standard versus non-standard housing conditions in male and female mice.

Methods

Adult C57BL/6 J mice were housed in either standard shoebox cages or in automated Herdsman 2 (HM2) cages and exposed to a two-bottle choice procedure with 3% or 6% ethanol versus water for 5 days. The HM2 cages use radiotracking devices to measure the fluid consumption of individual mice in an undisturbed and automated manner. In both housing conditions, mice were housed either at one or at four per cage.

Results

In standard cages, group housing of animals decreased alcohol consumption and water consumption. In HM2 cages, group housing significantly increased ethanol preference and decreased water intake. There were no significant differences in these effects between male and female animals. These observations were similar for 3 and 6% ethanol solutions but were more pronounced for the latter. The effects of social environment on ethanol preference in HM2 cages were accompanied by an increase in the number of approaches to the ethanol solution and a decrease in the number of approaches to water. The differences in ethanol intake could not be explained by differences in locomotor or exploratory activity as socially housed mice showed fewer non-consummatory visits to the ethanol solutions than single-housed animals. In addition, we observed that significant changes in behaviors measuring the approach to the fluid were not always accompanied by significant changes in fluid consumption, and vice versa, suggesting that it is important to assess both measures of motivation to consume alcohol.

Conclusion

Our results indicate that the direction of the effects of social environment on alcohol intake in mice depends on the non-social housing environment. Understanding mechanisms by which social and non-social housing conditions modulate alcohol intake could suggest approaches to counteract environmental factors enhancing hazardous alcohol consumption.

Role of social context in addiction etiology and recovery

While social context has long been considered central to substance use disorder prevention and treatment and many drug-taking events occur in social settings, experimental research on social context has historically been limited. Recent years have seen an emergence of concerted preclinical and human laboratory research documenting the direct impact of social context on substance use, delineating behavioral and neurobiological mechanisms underlying social influence's role. We review this emerging preclinical and human laboratory literature from a theoretical lens that considers distinct stages of the addiction process including drug initiation/acquisition, escalation, and recovery. A key conclusion of existing research is that the impact of the social environment is critically moderated by the drug-taking behavior and drug use history of a social peer. Specifically, while drug-free social contexts can reduce the likelihood of drug use initiation and act as a competitive non-drug alternative preventing escalation, drug-using peers can equally facilitate initiation and escalation through peer modeling as a contingent reward of use. Likewise, social context may facilitate recovery or serve as a barrier that increases the chances of a return to regular use. We conclude by discussing evidence-based treatments and recovery support services that explicitly target social mechanisms or that have identified social context as a mechanism of change within treatment. Ultimately, new areas for research including the expansion of drug classes studied and novel human laboratory designs are needed to further translate emerging findings into clinical practice.

A social contextual review of the effects of alcohol on emotion

Drinking and drinking problems are complex phenomena. Understanding the etiology of alcohol use disorder requires consideration of biological, psychological, and social processes. It is our view that the last of these dimensions is just beginning to receive adequate scrutiny. In this selective review, we discuss the concept of a biopsychosocial analysis of the effects of alcohol. After briefly addressing biological and psychological research on alcohol's emotional effects, we bid to make a case for the vital role that social processes play in understanding why people drink. The bulk of the paper describes research illustrating the contributions that a social psychological perspective can make to advance understanding of the rewarding effects of alcohol. Overall, studies incorporating social contexts have revealed reliable evidence that alcohol enhances emotional experience in many social environments and have identified socio-contextual variables that moderate responses to alcohol. Further, these studies have broadened the scope of constructs thought to be socially rewarding, including social bonding, relationship functioning, and humor enjoyment. Our analysis concludes by identifying research areas we believe would profit from additional research.

Social Interaction With Relapsed Partner Facilitates Cocaine Relapse in Rats

Social factors strongly contribute to drug use and relapse, and epidemiological studies have found that members of peer groups influence each other to use drugs. However, previous animal models mostly failed to incorporate social factors and demonstrate the effects of social partners on drug addiction and relapse. In the present study, we investigated the transfer of relapse to cocaine seeking between drug-addicted partners in rats. Male Sprague-Dawley rats were pair-housed and subjected to training and extinction of cocaine self-administration and conditioned place preference (CPP). 24 h after extinction test, the targeted rats interacted with a cocaine-primed (relapsed) partner or stranger, or saline-injected (unrelapsed) partner for 30 min, after which the targeted rats were tested for drug seeking behavior. We found that social interaction with a relapsed partner increased drug seeking behavior in cocaine self-administration and CPP models in rats, while social interaction with an unrelapsed partner or relapsed stranger had no effect on cocaine seeking. Moreover, the effect of social interaction on cocaine seeking could last for at least 1 day. Our findings demonstrate a facilitation effect of relapsed social partners on drug relapse in rats and provide a novel animal model for social transfer of drug relapse.

Opposite Roles for Cannabidiol and δ-9-Tetrahydrocannabinol in Psychotomimetic Effects of Cannabis Extracts: A Naturalistic Controlled Study

BACKGROUND

Although δ-9-tetrahydrocannabinol (THC), the main cannabinoid from the cannabis plant, is responsible for the psychotomimetic effects of cannabis, cannabidiol (CBD), the second most abundant cannabinoid in the cannabis plant, does not show any psychotomimetic effect. Cannabidiol has even been proposed to be antipsychotic and to counteract some of the psychotomimetic effects of THC. The aim of this study was to test the potential antipsychotomimetic effects of CBD.

METHOD

Eighteen members from a cannabis social club were tested for subjective and psychotomimetic effects under the effects of different full-spectrum cannabis extracts containing either THC, CBD, THC + CBD, or placebo in a naturalistic, randomized, double-blind, crossover, placebo-controlled study.

RESULTS

Results showed that participants under the effects of THC + CBD showed lower psychotomimetic scores in subjective scales when compared with THC alone. Subjective scores were lower under the effects of CBD and placebo when compared with THC + CBD. Cannabidiol and placebo did not show any psychotomimetic effect.

CONCLUSIONS

This study provides evidence for both the psychotomimetic effects of THC and the antipsychotomimetic effects of CBD when it is coadministered with THC in real-world situations, which can be very relevant for the clinical practice of medical cannabis. Ultimately, this study substantiates the link between the endocannabinoid system and psychotic-like symptoms and has important implications for the understanding of schizophrenia and the therapeutic potential of CBD as an antipsychotic. Lastly, we demonstrate how reliable methodologies can be implemented in real situations to collect valid ecological evidence outside classic laboratory settings.

Social facilitation of alcohol subjective effects in adolescents: Associations with subsequent alcohol use

RATIONALE

Laboratory research in adults indicates that alcohol-related subjective effects are enhanced under some social conditions. However, it is unknown whether this "social facilitation" of alcohol effects occurs in adolescents and is associated with alcohol use in the natural ecology.

OBJECTIVES

We examined associations of social facilitation of alcohol-related subjective effects with subsequent alcohol use among a relatively high-risk group of adolescents who reported drinking alcohol both with friends and alone.

METHODS

Los Angeles high school students from a prospective study (N = 142; 51% female; 10th graders) completed a baseline survey that assessed alcohol-related "positive" and "negative" subjective effects in two contexts: social (alcohol with friends) and solitary (alcohol alone); social facilitation was calculated as the difference between social and solitary. Students then completed five semi-annual surveys spanning 30 months (2014-2017) assessing 30-day alcohol use (days used, number of drinks, binge drinking).

RESULTS

Greater social facilitation of positive effects was significantly associated with greater number of alcohol use days (RR [95% CI] = 1.48 [1.19, 1.82]; p < .001), greater number of drinks (RR [95% CI] = 1.38 [1.14, 1.66]; p = .001), and greater odds of binge drinking (OR [95% CI] = 1.75 [1.20, 2.57]; p = .004). Similar associations were found with social positive effects. There were no significant associations between solitary positive effects-or any negative effects-and alcohol use outcomes.

CONCLUSIONS

Social facilitation can be measured outside of the laboratory. Relatively high-risk drinking adolescents who are more susceptible to the social facilitation of subjective alcohol effects are more likely to use more alcohol and binge drink.

Antecedents, concurrent correlates, and potential consequences of young adult solitary alcohol use

OBJECTIVE

Research on young adults has found solitary alcohol use to be positively associated with negative emotions, coping motives for drinking, and negative alcohol-related consequences, but most research has been cross-sectional and based on samples of college students. We examined associations across multiple time points within a sample that was diverse with respect to educational status and age.

METHODS

A community sample (N = 754, ages 18-26; 56% female) completed surveys at baseline, monthly for 2 years, and at 30-month postbaseline. Multilevel and single-level regression models assessed longitudinal and concurrent associations between solitary drinking and potential correlates, adjusting for frequency of alcohol use.

RESULTS

Moderate depressive symptoms at baseline were associated with a greater likelihood of solitary drinking in drinking months in the subsequent 2 years (Adjusted Odds Ratio [AOR] = 2.22, 95% CI [1.54-3.20]). During those 2 years, both depressive symptoms and coping motives were positively concurrently associated with solitary drinking at the between- and within-person level. Although solitary drinking in a particular month had a small and nonsignificant association with negative alcohol-related consequences, the proportion of drinking months that involved solitary drinking was positively associated with negative alcohol-related consequences across months. More solitary drinking during monthly data collection was associated with greater likelihoods of hazardous drinking and moderate depressive symptoms at 30-month follow-up, but these associations were not statistically significant after adjusting for earlier measures of drinking and depressive symptoms.

CONCLUSIONS

The findings point to the importance of considering the drinking context when screening and providing treatment for alcohol misuse. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Striatal activation to monetary reward is associated with alcohol reward sensitivity

One well-known phenotypic risk factor for the development of alcohol use disorder is sensitivity to the rewarding effects of alcohol. In the present study, we examined whether individuals who are sensitive to alcohol reward are also sensitive to nondrug rewards, thereby reflecting a broader individual difference risk factor. Specifically, we tested the hypothesis that subjective response to acute rewarding effects of alcohol would be related to neural activation during monetary reward receipt relative to loss (in the absence of alcohol). Community-recruited healthy young social drinkers (N = 58) completed four laboratory sessions in which they received alcohol (0.8 g/kg) and placebo in alternating order under double-blind conditions, providing self-report measures of subjective response to alcohol at regular intervals. At a separate visit 1-3 weeks later, they completed a reward-guessing game, the 'Doors' task, during fMRI in a drug-free state. Participants who reported greater motivation (i.e., wanting) to consume more alcohol after a single moderate dose of alcohol also exhibited greater neural activation in the bilateral ventral caudate and the nucleus accumbens during reward receipt relative to loss. Striatal activation was not related to other subjective ratings including alcohol-induced sedation, stimulation, or pleasure (i.e., feeling, liking). Our study is the first to show that measures of alcohol reward are related to neural indices of monetary reward in humans. These results support growing evidence that individual differences in responses to drug and nondrug reward are linked and together form a risk profile for drug use or abuse, particularly in young adults.

Associations between solitary drinking and increased alcohol consumption, alcohol problems, and drinking to cope motives in adolescents and young adults: a systematic review and meta-analysis

BACKGROUND AND AIMS

Emerging evidence suggests that solitary drinking may be an important early risk marker for alcohol use disorder. The current paper is the first meta-analysis and systematic review on adolescent and young adult solitary drinking to examine associations between solitary drinking and increased alcohol consumption, alcohol problems, and drinking to cope motives.

METHODS

PsychINFO, PubMed, and Google Scholar were searched using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology and a pre-registered International Prospective Register of Systematic Reviews (PROSPERO) protocol (no. CRD42020143449). Data from self-report questionnaires regarding negative correlates of solitary drinking (e.g. alcohol problems) and solitary drinking motives (e.g. drinking to cope) were pooled across studies using random-effects models. Studies included adolescents (aged 12-18 years) and young adults (mean age between 18 and 30 years or samples with the majority of participants aged 30 years or younger).

RESULTS

Meta-analytical results from 21 unique samples including 28,372 participants showed significant effects for the associations between solitary drinking and the following factors: increased alcohol consumption, r = 0.23, 95% confidence interval (CI) = 0.12, 0.33; drinking problems, r = 0.23, 95% CI = 0.13, 0.32; negative affect, r = 0.21, 95% CI = 0.16, 0.26; social discomfort, r = 0.17, 95% CI = 0.06, 0.27; negative reinforcement, r = 0.28, 95% CI = 0.24, 0.31; and positive reinforcement, r = 0.10, 95% CI = 0.03, 0.17. These associations were not moderated by age group (i.e. adolescent versus young adult), study quality, or differing solitary drinking definitions. Accounting for publication bias increased the effect sizes from r = 0.23 to 0.34 for alcohol consumption and from r = 0.23 to 0.30 for drinking problems, and lowered it from r = 0.10 to 0.06 and r = 0.17 to 0.11 for positive reinforcement and social discomfort, respectively.

CONCLUSIONS

Solitary drinking among adolescents and young adults appears to be associated with psychosocial/alcohol problems and drinking to cope motives.

The Feasibility, Tolerability, and Safety of Administering a Very High Alcohol Dose to Drinkers with Alcohol Use Disorder

INTRODUCTION

There remains a paucity of research quantifying alcohol's effects in drinkers with alcohol use disorder (AUD), particularly responses to very high alcohol doses (≥0.8 g/kg). As drinkers with AUD frequently engage in very heavy drinking (8 to 10 drinks/occasion), doses of ≤0.8 g/kg may lack ecological validity. The present study examined the feasibility, tolerability, and safety of administering a very high alcohol dose (1.2 g/kg) to non-treatment-seeking AUD participants.

METHODS

Sixty-one young adult AUD drinkers enrolled in the Chicago Social Drinking Project and completed 3 laboratory sessions at which they consumed a beverage with 1.2, 0.8, and 0.0 g/kg alcohol. Physiological responses (vital signs, nausea and vomiting, breath alcohol concentrations [BrAC]) were monitored throughout the sessions. After each session, participants completed a next-day survey of substance use, engagement in risky behaviors, and related consequences.

RESULTS

Overall, the sample demonstrated good compliance with study procedures; 93% of participants adhered to presession alcohol abstinence requirements (indicated by BrAC < 0.003 g/dl), with no participants exhibiting serious alcohol withdrawal symptoms at arrival to study visits. The 1.2 g/kg alcohol dose achieved an expected mean peak BrAC of 0.13 g/dl at 60 minutes after drinking, which was well tolerated; the majority of the sample did not experience nausea (70%) or vomiting (93%), and dose effects on vital signs were not clinically significant. Finally, we demonstrated that the 1.2 g/kg alcohol dose is safe and not associated with postsession consequences, including reduced sleep time, atypical substance use, accidents or injuries, and severe hangovers.

CONCLUSION

Results support the feasibility, tolerability, and safety of administering a very high alcohol dose to young adult drinkers with AUD within the context of a well-validated laboratory alcohol challenge paradigm. Utilizing an alcohol dose more consistent with naturalistic drinking patterns may foster greater ecological validity of laboratory paradigms for persons with moderate to severe AUD.

Female drinkers are more sensitive than male drinkers to alcohol-induced heart rate increase

The present study examined the acute effect of alcohol and its cues on autonomic and cardiovascular physiology, as indexed by changes in heart rate (HR), in a relatively large sample of healthy young adult men and women. Participants (27-31 years old, final N = 145) were administered an alcoholic beverage (n = 88; 52 women) or a placebo beverage (n = 57; 35 women) in a simulated bar. Target breath alcohol concentration (BrAC) was .08 g%. HR was recorded while participants were seated alone during an initial baseline assessment in a lab room; seated with others during preparation and administration of 2 beverages in a simulated bar; and seated alone in the lab room at ascending, peak, and descending BrAC. HR increased over time for participants in both beverage groups during beverage preparation. During beverage consumption, HR decreased over time in those who drank placebo whereas HR increased over time in those who drank alcohol, increasing at a faster rate in women compared to men. HR remained elevated at the ascending, peak, and descending limb assessments only in participants who drank alcohol with HR increasing over time at ascending BrAC in the women but not men. Sex differences in HR under alcohol were not explained by sex differences in body mass index, BrAC, recent alcohol use, or subjective stimulation. Our findings suggest that women may be more sensitive to alcohol-induced increases in HR, especially in environments where alcohol cues are abundant. This may have implications for cardiovascular risks associated with alcohol. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Considering Drug-Associated Contexts in Substance Use Disorders and Treatment Development

Environmental contexts that are reliably associated with the use of pharmacologically active substances are hypothesized to contribute to substance use disorders. In this review, we provide an updated summary of parallel preclinical and human studies that support this hypothesis. Research conducted in rats shows that environmental contexts that are reliably paired with drug use can renew extinguished drug-seeking behavior and amplify responding elicited by discrete, drug-predictive cues. Akin to drug-associated contexts, interoceptive drug stimuli produced by the psychopharmacological effects of drugs can also influence learning and memory processes that play a role in substance use disorders. Findings from human laboratory studies show that drug-associated contexts, including social stimuli, can have profound effects on cue reactivity, drug use, and drug-related cognitive expectancies. This translationally relevant research supports the idea that treatments for substance use disorders could be improved by considering drug-associated contexts as a factor in treatment interventions. We conclude this review with ideas for how to integrate drug-associated contexts into treatment-oriented research based on 4 approaches: pharmacology, brain stimulation, mindfulness-based relapse prevention, and cognitive behavioral group therapy. Throughout, we focus on alcohol- and tobacco-related research, which are two of the most prevalent and commonly misused drugs worldwide for which there are known treatments.

A Dynamic Analysis of the Effect of Alcohol Consumption on Humor Enjoyment in a Social Context

Many social interactions involve alcohol consumption, and drinking alcohol can lead to powerful increases in enjoyment in these social contexts. Yet we know almost nothing of the means by which alcohol enhances social experience. Importantly, since individuals in social contexts not only respond to environmental conditions, but can also actively generate these conditions, understanding alcohol's social enhancement within wholly unstructured social interaction presents challenges. To address this issue, the current study examines responses of individuals participating in a structured pleasurable experience in social context (humor presentation)-a drinking context with ecological-validity that permits us to test theories of alcohol-related social-enhancement through isolating responses to the controlled presentation of pleasurable stimuli (i.e., comedy punchlines). Participants (N = 513) were randomly-assigned to consume an alcoholic, placebo, or control beverage in the laboratory. Participants were video-recorded during presentation of a comedy routine in 3-person groups, and participants' Duchenne smiles were recorded on a frame-by-frame basis using the Facial Action Coding System. Comedy punchlines were coded by five raters and validated via an independently collected sample of participants (N = 30). Results of nested frailty survival models, controlling for the smiles of other group members, indicated a significant interaction between punchlines and alcohol in predicting smiles. Specifically, alcohol selectively increased smiling during times when no humorous stimuli were being presented, whereas there was no significant effect of alcohol on smiling in response to the humorous stimuli themselves. Findings highlight the importance of less intrinsically entertaining social moments for understanding alcohol-related social enhancement.

A multimodal investigation of contextual effects on alcohol's emotional rewards

Regular alcohol consumption in unfamiliar social settings has been linked to problematic drinking. A large body of indirect evidence has accumulated to suggest that alcohol's rewarding emotional effects-both negative-mood relieving and positive-mood enhancing-will be magnified when alcohol is consumed within unfamiliar versus familiar social contexts. But empirical research has never directly examined links between contextual familiarity and alcohol reward. In the current study, we mobilized novel ambulatory technology to examine the effect of social familiarity on alcohol reward in everyday drinking contexts while also examining how alcohol reward observed in these field contexts corresponds to reward observed in the laboratory. Heavy social drinking participants (N = 48, 50% male) engaged in an intensive week of ambulatory assessment. Participants wore transdermal alcohol sensors while they reported on their mood and took photographs of their social contexts in response to random prompts. Participants also attended 2 laboratory beverage-administration sessions, during which their emotional responses were assessed and transdermal sensors were calibrated to estimate breathalyzer readings (eBrACs). Results indicated a significant interaction between social familiarity and alcohol episode in everyday drinking settings, with alcohol enhancing mood to a greater extent in relatively unfamiliar versus familiar social contexts. Findings also indicated that drinking in relatively unfamiliar social settings was associated with higher eBrACs. Finally, results indicated a correspondence between some mood effects of alcohol experienced inside and outside the laboratory. This study presents a novel methodology for examining alcohol reward and indicates social familiarity as a promising direction for research seeking to explain problematic drinking. (PsycINFO Database Record

The Impact of Alcohol and Social Context on the Startle Eyeblink Reflex

BACKGROUND

Researchers have long sought to understand how individuals respond to alcohol in social settings with the aim of elucidating pathways of risk for alcohol use disorder (AUD). But studies that incorporate a social context are still outnumbered by those that examine alcohol's subjective effects among participants drinking alcohol in isolation. Further, perhaps due to the challenges of capturing automatic affective processes in these settings, prior studies of alcohol response in social context have relied mainly on self-report measures, and so relatively little is known about alcohol's psychophysiological effects in social settings.

METHODS

Using a novel paradigm that integrated alcohol-administration procedures, startle methodology, and social context, this study examined the impact of alcohol and social context on startle eyeblink reflex among 40 social drinkers.

RESULTS

Results indicated that there was a significant effect of group presence, indicating that startle magnitude was larger when people were alone than with others. There was a significant group presence-by-alcoholic beverage interaction, with the effect of alcohol being significantly larger when people were alone versus with others. These effects were found both for the startle habituation data and during the picture-viewing task.

CONCLUSIONS

Results of this study highlight the importance of considering the presence of other individuals for understanding alcohol response and mechanisms of AUD risk. Findings are discussed in light of both emotional and cognitive correlates of startle reflex magnitude. Future research should examine these effects within larger samples of participants and further explore mechanisms that might underlie these effects.

Perception of physical attractiveness when consuming and not consuming alcohol: a meta-analysis

BACKGROUND AND AIMS

Elucidating why people drink and why drinking can lead to negative psychosocial consequences remains a crucial task for alcohol researchers. Because drinking occurs typically in social settings, broader investigation of the associations between alcohol and social experience is needed to advance understanding of both the rewarding and hazardous effects of alcohol use. This review aimed to (a) estimate alcohol's relation to the perception of others' physical attractiveness and (b) suggest theoretical and methodological considerations that may advance the study of this topic.

METHODS

Systematic review of Scopus and PsycInfo databases was conducted to identify experimental and quasi-experimental studies, with either between- or within-subjects designs, that assessed attractiveness ratings provided by individuals who had and had not consumed alcohol (k = 16 studies, n = 1811). A meta-analysis was conducted to evaluate alcohol's aggregate association with physical attractiveness perceptions. Separate a priori secondary analyses examined alcohol's associations with perception of opposite-sex (k = 12 studies) and same-sex (k = 7 studies) attractiveness.

RESULTS

The primary analysis indicated that alcohol was related significantly to enhanced attractiveness perceptions [d = 0.19, 95% confidence interval (CI) = 0.05-0.32, P = 0.01; I2  = 5.28, 95% CI = 0.00-39.32]. Analysis of alcohol's association with perception of opposite-sex attractiveness similarly yielded a small, significant positive association (d = 0.30, 95% CI = 0.16-0.44, P < 0.01; I2  = 17.49, 95% CI = 0.00-57.75). Alcohol's relation to perception of same-sex attractiveness was not significant (d = 0.04, 95% CI = -0.18 to 0.26, P = 0.71; I2  = 54.08, 95% CI = 0.00-81.66).

CONCLUSIONS

Experimental and quasi-experimental studies suggest that consuming alcohol may have a small effect of increasing perceived attractiveness of people of the opposite sex.

Intra- and Interindividual Variability in the Behavioral, Affective, and Perceptual Effects of Alcohol Consumption in a Social Context

BACKGROUND

We examined the influence of interindividual differences in alcohol use on the intraindividual associations of drinking occurrence with interpersonal behaviors, affect, and perceptions of others during naturally occurring social interactions.

METHODS

For 14 consecutive days, 219 psychology freshmen (55% female; M_age  = 20.7 years, SD = 2.18) recorded their behaviors, affect, and perceptions in social interactions soon after an interpersonal event occurred. Interpersonal behaviors and perceptions were assessed in terms of dominance-submissiveness and agreeableness-quarrelsomeness. Participants also reported the number of alcoholic drinks consumed within 3 hours of each interaction. We considered the intraindividual associations of (i) having a drinking episode and (ii) the number of drinks during an episode with behaviors, affect, and perceptions and examined interindividual differences in drinking frequency and intensity during social interactions as potential moderators of these associations.

RESULTS

Social drinking frequency and intensity moderated the associations between drinking episode and behaviors, affect, and perceptions in social interactions. During a drinking episode, more frequent social drinkers perceived others as more dominant than less frequent social drinkers. During a drinking episode in which more alcohol was consumed than usual, more frequent social drinkers also reported behaving more dominantly and experiencing less pleasant affect.

CONCLUSIONS

As more frequent social drinkers had different interpersonal responses to drinking than less frequent social drinkers, including when they had consumed larger amounts of alcohol than usual, our results suggest a differential susceptibility to the effects of alcohol during naturally occurring social interactions among drinkers with varying drinking frequency.

Considering the context: social factors in responses to drugs in humans

BACKGROUND

Drugs are typically used in social settings. Here, we consider two factors that may contribute to this observation: (i) the presence of other people may enhance the positive mood effects of a drug, and conversely, (ii) drugs may enhance the value of social stimuli.

METHODS

We review evidence from controlled laboratory studies with human volunteers, which investigated either of these interactions between social factors and responses to drugs. We examine the bidirectional effects of social stimuli and single doses of alcohol, stimulants, opioids, and cannabis.

RESULTS

All four classes of drugs interact with social contexts, but the nature of these interactions varies across drugs, and depends on whether the context is positive or negative.

CONCLUSIONS

Alcohol and stimulant drugs enhance the attractiveness of social stimuli and the desire to socialize, and social contexts, in turn, enhance these drugs' effects. In contrast, opioids and cannabis have subtler effects on social interactions and their effects are less influenced by the presence of others. Overall, there is stronger evidence that drugs enhance positive social contexts than that they dampen the negativity of unpleasant social settings. Controlled research is needed to understand the interactions between drugs of abuse and social contexts, to model and understand the determinants of drug use outside the laboratory.

Animal models of drug addiction: Where do we go from here?

Compulsion and impulsivity are both primary features of drug addiction. Based on decades of animal research, we have a detailed understanding of the factors (both environmental and physiological) that influence compulsive drug use, but still know relatively little about the impulsive aspects of drug addiction. This review outlines our current knowledge of the relationship between impulsivity and drug addiction, focusing on cognitive and motor impulsivity, which are particularly relevant to this disorder. Topics to be discussed include the influence of chronic drug administration on impulsivity, the mechanisms that may explain drug-induced impulsivity, and the role of individual differences in the development of impulsive drug use. In addition, the manner in which contemporary theories of drug addiction conceptualize the relationship between impulsivity and compulsion is examined. Most importantly, this review emphasizes a critical role for animal research in understanding the role of impulsivity in the development and maintenance of drug addiction.

The effects of alcohol on emotion in social drinkers

Understanding why people drink alcohol and in some cases develop drinking problems has long puzzled researchers, clinicians, and patients alike. In the mid-1940s and early 1950s, experimental research began to systematically investigate alcohol's hedonic properties. Presumably, alcohol consumption would prove reinforcing as a consequence of its capacity either to relieve stress or to brighten positive emotional experiences. This article reviews experimental research through the years examining the impact of alcohol on both the relief of negative affect and the enhancement of positive affect. It covers initial accounts that emphasized direct pharmacological effects of ethanol on the central nervous system. These early studies offered surprisingly tepid support for the premise that alcohol improved emotional states. Next, studies conducted in the 1970s are considered. Informed by social learning theory and employing advances derived from experimental psychology, this research sought to better understand the complex effects of alcohol on emotion. Coverage of this work is followed by discussion of current formulations, which integrate biological and behavioral approaches with the study of cognitive, affective, and social processes. These current perspectives provide insight into the particular conditions under which alcohol can boost emotional experiences. Finally, future research directions and clinical implications are considered.

Extraversion and the Rewarding Effects of Alcohol in a Social Context

The personality trait of extraversion has been linked to problematic drinking patterns. Researchers have long hypothesized that such associations are attributable to increased alcohol-reward sensitivity among extraverted individuals, and surveys suggest that individuals high in extraversion gain greater mood enhancement from alcohol than those low in extraversion. Surprisingly, however, alcohol administration studies have not found individuals high in extraversion to experience enhanced mood following alcohol consumption. Of note, prior studies have examined extraverted participants-individuals who self-identify as being highly social-consuming alcohol in isolation. In the present research, we used a group drinking paradigm to examine whether individuals high in extraversion gained greater reward from alcohol than did those low in extraversion and, further, whether a particular social mechanism (partners’ Duchenne smiling) might underlie alcohol reward sensitivity among extraverted individuals. Social drinkers (n 720) consumed a moderate dose of alcohol, placebo, or control beverage in groups of 3 over the course of 36 min. This social interaction was video-recorded, and Duchenne smiling was coded using the Facial Action Coding System. Results indicated that participants high in extraversion reported significantly more mood enhancement from alcohol than did those low in extraversion. Further, mediated moderation analyses focusing on Duchenne smiling of group members indicated that social processes fully and uniquely accounted for alcohol reward-sensitivity among individuals high in extraversion. Results provide initial experimental evidence that individuals high in extraversion experience increased mood-enhancement from alcohol and further highlight the importance of considering social processes in the etiology of alcohol use disorder.

The impact of social context on cigarette self-administration in nondependent smokers

Tobacco use in nondependent smokers (i.e. chippers) is believed to be largely determined by situational factors including social context. However, little empirical research has examined how different social contexts impact chippers' smoking behaviour. Twenty-eight (16 men) chippers completed two laboratory sessions where they were offered an opportunity to self-administer puffs of their preferred tobacco brand using a progressive ratio task. During an individual session, participants self-administered cigarettes alone and during a paired session, they self-administered cigarettes with a coparticipant who was also smoking. The strongest predictors for number of self-administered puffs and breakpoint during the paired session were coparticipants' number of puffs and breakpoint, respectively (P<0.001), followed by puffs taken and breakpoint during the individual session (P<0.01). Current smoking frequency (cigarettes/week) did not significantly predict puffs taken or breakpoint during the paired session. Latency to cigarette self-administration during the paired session was correlated positively with coparticipants' latency (P<0.05), but not with latency during the individual session or cigarettes per week. The findings suggest that the presence of another smoker exerts an important influence on the quantity of chippers' smoking behaviour, such that chippers match their smoking behaviour to that of other smokers in their proximate environment.

Drug effects on responses to emotional facial expressions: recent findings

Many psychoactive drugs increase social behavior and enhance social interactions, which may, in turn, increase their attractiveness to users. Although the psychological mechanisms by which drugs affect social behavior are not fully understood, there is some evidence that drugs alter the perception of emotions in others. Drugs can affect the ability to detect, attend to, and respond to emotional facial expressions, which in turn may influence their use in social settings. Either increased reactivity to positive expressions or decreased response to negative expressions may facilitate social interaction. This article reviews evidence that psychoactive drugs alter the processing of emotional facial expressions using subjective, behavioral, and physiological measures. The findings lay the groundwork for better understanding how drugs alter social processing and social behavior more generally.

The Alcohol Sensitivity Questionnaire: Evidence for Construct Validity

BACKGROUND

Variability in sensitivity to the acute effects of alcohol is an important risk factor for the development of alcohol use disorder (AUD). The most commonly used retrospective self-report measure of sensitivity, the Self-Rating of the Effects of Alcohol (SRE) form, queries a limited number of alcohol effects and relies on respondents' ability to recall experiences that might have occurred in the distant past. Here, we investigated the construct validity of an alternative measure that queries a larger number of alcohol effects, the Alcohol Sensitivity Questionnaire (ASQ), and compared it to the SRE in predicting momentary subjective responses to an acute dose of alcohol.

METHODS

Healthy young adults (N = 423) completed the SRE and the ASQ and then were randomly assigned to consume either alcohol or a placebo beverage (between-subjects manipulation). Stimulation and sedation (Biphasic Alcohol Effects Scale) and subjective intoxication were measured multiple times after drinking.

RESULTS

Hierarchical linear models showed that the ASQ reliably predicted each of these outcomes following alcohol but not placebo consumption, provided unique prediction beyond that associated with differences in recent alcohol involvement, and was preferred over the SRE (in terms of model fit) in direct model comparisons of stimulation and sedation.

CONCLUSIONS

The ASQ compared favorably with the better-known SRE in predicting increased stimulation and reduced sedation following an acute alcohol challenge. The ASQ appears to be a valid self-report measure of alcohol sensitivity and therefore holds promise for identifying individuals at-risk for AUD and related problems.

A Preliminary Investigation of Individual Differences in Subjective Responses to D-Amphetamine, Alcohol, and Delta-9-Tetrahydrocannabinol Using a Within-Subjects Randomized Trial

Polydrug use is common, and might occur because certain individuals experience positive effects from several different drugs during early stages of use. This study examined individual differences in subjective responses to single oral doses of d-amphetamine, alcohol, and delta-9-tetrahydrocannabinol (THC) in healthy social drinkers. Each of these drugs produces feelings of well-being in at least some individuals, and we hypothesized that subjective responses to these drugs would be positively correlated. We also examined participants’ drug responses in relation to personality traits associated with drug use. In this initial, exploratory study, 24 healthy, light drug users (12 male, 12 female), aged 21–31 years, participated in a fully within-subject, randomized, counterbalanced design with six 5.5-hour sessions in which they received d-amphetamine (20mg), alcohol (0.8 g/kg), or THC (7.5 mg), each paired with a placebo session. Participants rated the drugs’ effects on both global measures (e.g. feeling a drug effect at all) and drug-specific measures. In general, participants’ responses to the three drugs were unrelated. Unexpectedly, “wanting more” alcohol was inversely correlated with “wanting more” THC. Additionally, in women, but not in men, “disliking” alcohol was negatively correlated with “disliking” THC. Positive alcohol and amphetamine responses were related, but only in individuals who experienced a stimulant effect of alcohol. Finally, high trait constraint (or lack of impulsivity) was associated with lower reports of liking alcohol. No personality traits predicted responses across multiple drug types. Generally, these findings do not support the idea that certain individuals experience greater positive effects across multiple drug classes, but instead provide some evidence for a “drug of choice” model, in which individuals respond positively to certain classes of drugs that share similar subjective effects, and dislike other types of drugs.

Speech volume indexes sex differences in the social-emotional effects of alcohol

Men and women differ dramatically in their rates of alcohol use disorder (AUD), and researchers have long been interested in identifying mechanisms underlying male vulnerability to problem drinking. Surveys suggest that social processes underlie sex differences in drinking patterns, with men reporting greater social enhancement from alcohol than women, and all-male social drinking contexts being associated with particularly high rates of hazardous drinking. But experimental evidence for sex differences in social-emotional response to alcohol has heretofore been lacking. Research using larger sample sizes, a social context, and more sensitive measures of alcohol's rewarding effects may be necessary to better understand sex differences in the etiology of AUD. This study explored the acute effects of alcohol during social exchange on speech volume--an objective measure of social-emotional experience that was reliably captured at the group level. Social drinkers (360 male; 360 female) consumed alcohol (.82 g/kg males; .74 g/kg females), placebo, or a no-alcohol control beverage in groups of 3 over 36-min. Within each of the 3 beverage conditions, equal numbers of groups consisted of all males, all females, 2 females and 1 male, and 1 female and 2 males. Speech volume was monitored continuously throughout the drink period, and group volume emerged as a robust correlate of self-report and facial indexes of social reward. Notably, alcohol-related increases in group volume were observed selectively in all-male groups but not in groups containing any females. Results point to social enhancement as a promising direction for research exploring factors underlying sex differences in problem drinking.

Animal models of social contact and drug self-administration

Social learning theories of drug abuse propose that individuals imitate drug use behaviors modeled by social peers, and that these behaviors are selectively reinforced and/or punished depending on group norms. Historically, animal models of social influence have focused on distal factors (i.e., those factors outside the drug-taking context) in drug self-administration studies. Recently, several investigators have developed novel models, or significantly modified existing models, to examine the role of proximal factors (i.e., those factors that are immediately present at the time of drug taking) on measures of drug self-administration. Studies using these newer models have revealed several important conclusions regarding the effects of social learning on drug abuse: 1) the presence of a social partner influences drug self-administration, 2) the behavior of a social partner determines whether social contact will increase or decrease drug intake, and 3) social partners can model and imitate specific patterns of drug self-administration. These findings are congruent with those obtained in the human laboratory, providing support for the cross-species generality and validity of these preclinical models. This mini-review describes in detail some of the preclinical animal models used to study social contact and drug self-administration to guide future research on social learning and drug abuse.

MDMA: a social drug in a social context

RATIONALE

The drug ±3,4-methylenedioxymethamphetamine (MDMA, "ecstasy," "molly") is thought to produce prosocial effects and enhance social interaction. However, in most laboratory studies to date, the participants have been tested under nonsocial conditions, which may not simulate the effects the drug produces in more naturalistic social settings.

METHODS

Healthy experienced MDMA users participated in three laboratory sessions in which they received MDMA (0.5 or 1.0 mg/kg or placebo, double blind). They were randomly assigned to one of three social conditions, in which they were tested alone (solitary (SOL); N = 10), in the presence of a research assistant (research assistant present (RAP); N = 11) or in the presence of another participant who also received the drug (other participant present (OPP); N = 11).

RESULTS

As expected, MDMA increased heart rate and blood pressure and produced positive subjective effects in all the three groups. It also increased ratings of attractiveness of another person and increased social interaction in RAP and OPP. The social context affected certain responses to the drug. The effects of MDMA were greater in the OPP condition, compared to the SOL or RAP conditions, on measures of "feel drug," "dizzy," and on cardiovascular. But responses to the drug on other measures, including social behavior, did not differ across the conditions.

CONCLUSIONS

These findings provide some support for the idea that drugs produce greater effects when they are used in the presence of other drug users. However, the influence of the social context was modest, and it remains to be determined whether other variables related to social context would substantially alter the effects of MDMA or other drugs.

A family history of Type 1 alcoholism differentiates alcohol consumption in high cortisol responders to stress

BACKGROUND

The differentiation between high and low cortisol responders to stress is of interest in determining the risk factors which may, along with genetic vulnerability, influence alcohol intake.

STUDY 1

METHODS

Thirty-two healthy volunteers, family history positive to alcoholism (FHP, n = 16) and family history negative (FHN, n = 16) attended two laboratory sessions during which alcohol or placebo was offered.

RESULTS

There were no differences in consumption of alcohol or placebo between FHP and FHN subjects. STUDY 2:

METHODS

Fifty-eight healthy social drinkers, FHP (n = 27) and FHN (n = 31) attended two laboratory sessions. They were administered either alcohol or placebo in both sessions they attended. All subjects underwent either a stress task (the Trier Social Stress Test, TSST) or a stress-free period, at two separate occasions, before being offered beverage. After the salivary cortisol analysis, subjects in each group were divided into high (HCR) or low (LCR) cortisol responders.

RESULTS

After stress, subjects who were FHP-HCR consumed more alcohol than FHN-HCR. There were no differences in the placebo intake between FHP and FHN subjects regardless of their cortisol response.

CONCLUSIONS

This result indicates that stress promotes alcohol consumption only in subjects with a family history of Type 1 alcoholism who show an increase in cortisol response to stress. This behaviour is similar to that previously observed in alcohol dependent individuals after stress and thus could represent an endophenotype posing a risk for future development of alcohol use disorders.

MDMA effects consistent across laboratories

RATIONALE

Several laboratories have conducted placebo-controlled drug challenge studies with 3,4-methylenedioxymethamphetamine (MDMA), providing a unique source of data to examine the reliability of the acute effects of the drug across subject samples and settings. We examined the subjective and physiological responses to the drug across three different laboratories and investigated the influence of prior MDMA use.

METHODS

Overall, 220 healthy volunteers with varying levels of previous MDMA experience participated in laboratory-based studies in which they received placebo or MDMA orally (1.5 mg/kg or 125-mg fixed dose) under double-blind conditions. Cardiovascular and subjective effects were assessed before and repeatedly after drug administration. The studies were conducted independently by investigators in Basel, San Francisco, and Chicago.

RESULTS

Despite methodological differences between the studies and differences in the subjects' drug use histories, MDMA produced very similar cardiovascular and subjective effects across the sites. The participants' prior use of MDMA was inversely related to feeling "Any Drug Effect" only at sites testing more experienced users.

CONCLUSIONS

These data indicate that the pharmacological effects of MDMA are robust and highly reproducible across settings. There was also modest evidence for tolerance to the effects of MDMA in regular users.

A social-attributional analysis of alcohol response

Conventional wisdom and survey data indicate that alcohol is a social lubricant and is consumed for its social effects. In contrast, the experimental literature examining alcohol's effects within a social context reveals that alcohol does not consistently enhance social-emotional experience. We identify a methodological factor that might explain inconsistent alcohol-administration findings, distinguishing between studies featuring unscripted interactions among naïve participants (k = 18) and those featuring scripted social interactions with individuals identified as study confederates (k = 18). While 89% of naïve-participant studies find positive effects of alcohol on mood (d = 0.5), only 11% of confederate studies find evidence of significant alcohol-related mood enhancement (d = -0.01). The naïve-participant versus confederate distinction remains robust after controlling for various moderators including stress manipulations, gender, group size, anxiety outcome measure, and within-group consistency of beverage assignment. Based on the findings of our review, we propose a multidimensional, social-attributional framework for understanding alcohol-related reward. Borrowing organizing principles from attribution theory, the social-attributional approach predicts that alcohol will enhance mood when negative outcomes are perceived to be unstable and/or self-relevant. Our framework proposes that alcohol's effects within a social context are largely explained by its tendency to free individuals from preoccupation with social rejection, allowing them to access social rewards. The social-attributional approach represents a novel framework for integrating distinct, well-validated concepts derived from several theories of alcohol's effects. It further presents promising lines of inquiry for future research examining the role of social factors in alcohol reward and addiction susceptibility.

Effects of MDMA and Intranasal oxytocin on social and emotional processing

MDMA (± 3,4-methylenedioxymethamphetamine, 'ecstasy') is used recreationally, reportedly because it increases feelings of empathy, sociability, and interpersonal closeness. One line of evidence suggests that MDMA produces these effects by releasing oxytocin, a peptide involved in social bonding. In the current study, we investigated the acute effects of MDMA and oxytocin on social and emotional processing in healthy human volunteers. MDMA users (N = 65) participated in a 4-session, within-between-subjects study in which they received oral MDMA (0.75, 1.5 mg/kg), intranasal oxytocin (20 or 40 IU), or placebo under double-blind conditions. The primary outcomes included measures of emotion recognition and sociability (desire to be with others). Cardiovascular and subjective effects were also assessed. As expected, MDMA dose-dependently increased heart rate and blood pressure and feelings of euphoria (eg, 'High' and 'Like Drug'). On measures of social function, MDMA impaired recognition of angry and fearful facial expressions, and the larger dose (1.5 mg/kg) increased desire to be with others, compared with placebo. Oxytocin produced small but significant increases in feelings of sociability and enhanced recognition of sad facial expressions. Additionally, responses to oxytocin were related to responses to MDMA with subjects on two subjective measures of sociability. Thus, MDMA increased euphoria and feelings of sociability, perhaps by reducing sensitivity to subtle signs of negative emotions in others. The present findings provide only limited support for the idea that oxytocin produces the prosocial effects of MDMA.

Alcohol challenge responses predict future alcohol use disorder symptoms: a 6-year prospective study

BACKGROUND

Propensity for alcohol misuse may be linked to an individuals' response to alcohol. This study examined the role of alcohol response phenotypes to future drinking problems.

METHODS

One hundred four young heavy social drinkers participated in a within-subject, double-blind, placebo-controlled laboratory alcohol challenge study with 6-year follow-up. Participants were examined for subjective responses before and after receiving an intoxicating dose of alcohol (.8 g/kg) or a placebo beverage, given in random order. Follow-up was conducted in 5 waves over 6 years after the sessions to assess drinking behaviors and alcohol use disorder (AUD) symptoms. Retention was high with 98% (509 of 520) of possible follow-ups completed.

RESULTS

Greater sensitivity to alcohol, in terms of stimulation and rewarding effects (like, want more) and lower sensitivity to alcohol sedation predicted greater number of AUD symptoms through 6 years of follow-up. Cluster analyses revealed that for half the sample, increasing levels of stimulation and liking were predictors of more AUD symptoms with the other half divided between those showing like and want more and want more alone as significant predictors.

CONCLUSIONS

The findings extend previous findings and offer new empirical insights into the propensity for excessive drinking and alcohol problems. Heightened alcohol stimulation and reward sensitivity robustly predicted more alcohol use disorder symptoms over time associated with greater binge-drinking frequency. These drinking problems were maintained and progressed as these participants were entering their third decade of life, a developmental interval when continued alcohol misuse becomes more deviant.

The biphasic effects of moderate alcohol consumption with a meal on ambiance-induced mood and autonomic nervous system balance: a randomized crossover trial

Background

The pre-drinking mood state has been indicated to be an important factor in the mood effects of alcohol. However, for moderate alcohol consumption there are no controlled studies showing this association. Also, the mood effects of consuming alcohol combined with food are largely unknown. The aim of this study was to investigate the effects of moderate alcohol combined with a meal on ambiance-induced mood states. Furthermore effects on autonomic nervous system activity were measured to explore physiological mechanisms that may be involved in changes of mood state.

Methods

In a crossover design 28 women (age 18–45 y, BMI 18.5–27 kg/m²) were randomly allocated to 4 conditions in which they received 3 glasses of sparkling white wine (30 g alcohol) or alcohol-free sparkling white wine while having dinner in a room with either a pleasant or unpleasant created ambiance. Subjects filled out questionnaires (B-BAES, POMS and postprandial wellness questionnaire) at different times. Skin conductance and heart rate variability were measured continuously.

Results

Moderate alcohol consumption increased happiness scores in the unpleasant, but not in the pleasant ambiance. Alcohol consumption increased happiness and stimulation feelings within 1 hour and increased sedative feelings and sleepiness for 2.5 hour. Skin conductance was increased after alcohol within 1 hour and was related to happiness and stimulation scores. Heart rate variability was decreased after alcohol for 2 hours and was related to mental alertness.

Conclusion

Mood inductions and autonomic nervous system parameters may be useful to evaluate mood changes by nutritional interventions. Moderate alcohol consumption elevates happiness scores in an unpleasant ambiance. However, drinking alcohol during a pleasant mood results in an equally positive mood state.

Trial Registration

Clinicaltrials.gov NCT01426022.

In the company of others: social factors alter acute alcohol effects

RATIONALE

Alcohol is usually consumed in social contexts. However, the drug has been studied mainly under socially isolated conditions, and our understanding of how social setting affects response to alcohol is limited.

OBJECTIVES

The current study compared the subjective, physiological, and behavioral effects of a moderate dose of alcohol in moderate social drinkers who were tested in either a social or an isolated context and in the presence of others who had or had not consumed alcohol.

METHODS

Healthy men and women were randomly assigned to either a social group tested in pairs (SOC; N = 24), or an isolated group tested individually (ISO; N = 20). They participated in four sessions, in which they received oral alcohol (0.8 g/kg) or placebo on two sessions each, in quasi-randomized order under double-blind conditions. In the SOC condition, the drug conditions of the co-participants were varied systematically: on two sessions, both participants received the same substance (placebo or alcohol) and on the other two sessions one received alcohol while the other received placebo. Cardiovascular measures, breath alcohol levels, and mood were assessed at regular intervals, and measures of social interaction were obtained in the SOC group.

RESULTS

Alcohol produced greater effects on certain subjective measures in the SOC condition compared with the ISO condition, including feelings of intoxication and stimulation, but not on other measures such as feeling sedated or high, or on cardiovascular measures. Within the SOC condition, participants rated themselves as more intoxicated when their partner received alcohol, and paired subjects interacted more when at least one participant received alcohol.

CONCLUSIONS

The presence of others enhances some of the subjective and behavioral effects of alcohol, especially the presence of another intoxicated individual. This enhancement of alcohol effects may explain, in part, why it is used in a social context.

The differential contributions of teen drinking homophily to new and existing friendships: An empirical assessment of assortative and proximity selection mechanisms

Alcohol use is pervasive in adolescence. Though most research is concerned with how friends influence drinking, alcohol is also important for connecting teens to one another. Prior studies have not distinguished between new friendship creation, and existing friendship durability, however. We argue that accounting for distinctions in creation-durability processes is critical for understanding the selection mechanisms drawing drinkers into homophilous friendships, and the social integration that results. In order to address these issues, we appliedstochastic actor based models of network dynamics to National Longitudinal Study of Adolescent Health data. Adolescents only modestly prefer new friendships with others who drinker similarly, but greatly prefer friends who indirectly connect them to homophilous drinkers. These indirect homophilous drinker relationships are shorter lived, however, and suggest that drinking is a social focus that connects adolescents via proximity, rather than assortativity. These findings suggest that drinking leads to more situational and superficial social integration.

The effects of alcohol on the emotional displays of Whites in interracial groups

Discomfort during interracial interactions is common among Whites in the U.S. and is linked to avoidance of interracial encounters. While the negative consequences of interracial discomfort are well-documented, understanding of its causes is still incomplete. Alcohol consumption has been shown to decrease negative emotions caused by self-presentational concern but increase negative emotions associated with racial prejudice. Using novel behavioral-expressive measures of emotion, we examined the impact of alcohol on displays of discomfort among 92 White individuals interacting in all-White or interracial groups. We used the Facial Action Coding System and comprehensive content-free speech analyses to examine affective and behavioral dynamics during these 36-min exchanges (7.9 million frames of video data). Among Whites consuming nonalcoholic beverages, those assigned to interracial groups evidenced more facial and speech displays of discomfort than those in all-White groups. In contrast, among intoxicated Whites there were no differences in displays of discomfort between interracial and all-White groups. Results highlight the central role of self-presentational concerns in interracial discomfort and offer new directions for applying theory and methods from emotion science to the examination of intergroup relations.

Effects of delta-9-tetrahydrocannabinol on evaluation of emotional images

There is growing evidence that drugs of abuse alter processing of emotional information in ways that could be attractive to users. Our recent report that Δ⁹-tetrahydrocannabinol (THC) diminishes amygdalar activation in response to threat-related faces suggests that THC may modify evaluation of emotionally-salient, particularly negative or threatening, stimuli. In this study, we examined the effects of acute THC on evaluation of emotional images. Healthy volunteers received two doses of THC (7.5 and 15 mg; p.o.) and placebo across separate sessions before performing tasks assessing facial emotion recognition and emotional responses to pictures of emotional scenes. THC significantly impaired recognition of facial fear and anger, but it only marginally impaired recognition of sadness and happiness. The drug did not consistently affect ratings of emotional scenes. THC's effects on emotional evaluation were not clearly related to its mood-altering effects. These results support our previous work, and show that THC reduces perception of facial threat. Nevertheless, THC does not appear to positively bias evaluation of emotional stimuli in general.

Subjective perceptions associated with the ascending and descending slopes of breath alcohol exposure vary with recent drinking history

BACKGROUND

The differentiator model predicts that individuals with a positive family history of alcoholism (FHA) or heavy alcohol consumers will feel more sensitive to the effects of alcohol on the ascending phase of the blood alcohol content while feeling less sedated on the descending phase. This study tested whether subjective perceptions are sensitive to the slope of breath alcohol concentration (BrAC) and whether that sensitivity is associated with an FHA and/or recent drinking history (RDH).

METHODS

Family-history-positive (FHP, n = 27) and family-history-negative (FHN, n = 27) young adult nondependent drinkers were infused intravenously with alcohol in 2 sessions separated by 1 week. After 20 minutes, one session had an ascending BrAC (+3.0 mg%/min), while the other session had a descending BrAC (-1 mg%/min). The BrAC for both sessions at this point was approximately 60 mg%, referred to as the crossover point. Subjective perceptions of intoxication, high, stimulated, and sedation were sampled frequently and then interpolated to the crossover point. Within-subject differences between ascending and descending responses were examined for associations with FHA and/or RDH.

RESULTS

Recent moderate drinkers reported increased perceptions of feeling intoxicated (p < 0.023) and high (p < 0.023) on the ascending slope compared with the descending slope. In contrast, recent light drinkers felt more intoxicated and high on the descending slope.

CONCLUSIONS

Subjective perceptions in young adult social drinkers depend on the slope of the BrAC when examined in association with RDH. These results support the differentiator model hypothesis concerning the ascending slope and suggest that moderate alcohol consumers could be at risk for increased alcohol consumption because they feel more intoxicated and high on the ascending slope. Subjects did not feel less sedated on the descending slope, contrary to the differentiator model but replicating several previous studies.

DRD4 polymorphism moderates the effect of alcohol consumption on social bonding

Development of interpersonal relationships is a fundamental human motivation, and behaviors facilitating social bonding are prized. Some individuals experience enhanced reward from alcohol in social contexts and may be at heightened risk for developing and maintaining problematic drinking. We employed a 3 (group beverage condition) ×2 (genotype) design (N = 422) to test the moderating influence of the dopamine D4 receptor gene (DRD4 VNTR) polymorphism on the effects of alcohol on social bonding. A significant gene x environment interaction showed that carriers of at least one copy of the 7-repeat allele reported higher social bonding in the alcohol, relative to placebo or control conditions, whereas alcohol did not affect ratings of 7-absent allele carriers. Carriers of the 7-repeat allele were especially sensitive to alcohol's effects on social bonding. These data converge with other recent gene-environment interaction findings implicating the DRD4 polymorphism in the development of alcohol use disorders, and results suggest a specific pathway by which social factors may increase risk for problematic drinking among 7-repeat carriers. More generally, our findings highlight the potential utility of employing transdisciplinary methods that integrate genetic methodologies, social psychology, and addiction theory to improve theories of alcohol use and abuse.

Solitary versus social drinking: an experimental study on effects of social exposures on in situ alcohol consumption

BACKGROUND

Whereas the effects of modeling and of drinking contexts on alcohol use are documented, studies are lacking regarding the effect of given social exposures on actual alcohol consumption during drinking episodes (i.e., in situ alcohol consumption, the quantity of alcohol actually ingested in given occasion, e.g., in grams).

METHODS

Applying the experimental paradigms, our study investigates the impact of social condition (alone vs. with others) on in situ alcohol consumption (analog measurements) of 123 young adults who participated in 2 wine-tasting sessions (one together with others, i.e., group condition; 1 solitary, i.e., individual condition: the sequence of participation was assigned at random). Bivariate and multivariate analyses, that is, paired- and independent-samples t-tests and repeated measure analysis of variance, were applied to investigate the effects through both transversal and longitudinal perspectives.

RESULTS

In the first session, higher average amounts of alcohol were consumed in the group condition compared with the individual one. Conversely, higher average consumption was recorded in the individual compared with the group condition in the second session. Considering simultaneously data from the 2 experimental sessions demonstrated that subjects consumed higher amounts of alcohol in individual condition when this condition was organized subsequent and not prior to the group condition. Yet, alcohol consumption in group condition appeared to not vary between the 2 sessions.

CONCLUSIONS

Results first highlight the effects of social condition on in situ alcohol consumption. However, they also suggest that in situ exposition to others drinking is possibly involved in shaping the perception of context-related drinking norms, which might further influence subsequent drinking behaviors in an analogous context. Beyond the issues of imitation effects, these findings raise the issues of the development of preventive initiatives aiming to induce changes in individuals' perception of context-specific drinking norms.

Methamphetamine self-administration by humans subjected to abrupt shift and sleep schedule changes

RATIONALE

Methamphetamine attenuates disruptions that occur after changes in work shifts. The reinforcing effects of the drug during shift work have yet to be characterized.

OBJECTIVES

This study examined methamphetamine-related mood, performance, and reinforcing effects during simulated shift work.

MATERIALS AND METHODS

Ten volunteers (four women and six men) completed this 19-day study. Participants were given an opportunity to self-administer oral methamphetamine (10 mg) or receive a $1 voucher before and after an 8-h work period for four consecutive days under two shift conditions: (1) "day shift" in which they went to bed at 2400 hours and woke up at 0800 hours and (2) "night shift" when they went to bed at 1600 hours and woke up at 2400 hours. Thus, participants completed task batteries either from 0815 to 1715 hours or from 0015 to 0915 hours. Shift conditions alternated three times during the study and were separated by an "off" day.

RESULTS

Night-shift work disrupted psychomotor task performance and some ratings of mood, especially on the first night. Consistent with this, participants chose to take methamphetamine significantly more often on the first night-shift night compared with the first day-shift day. Regardless of shift condition, however, participants selected markedly more methamphetamine doses before the work period than after it (73% versus 34%).

CONCLUSIONS

These data show that methamphetamine self-administration occurred more often before work rather than after work, suggesting that the use of stimulants by shift workers may be one strategy employed to meet behavioral demands especially under conditions engendering poor performance, fatigue, and/or sleep disruptions.

Marijuana and tobacco exposure predict affect-regulation expectancies in dual users

In order to better compare affect-related expectancies for tobacco and marijuana smoking, associations of marijuana and tobacco exposure to negative affect reduction (NAR), positive affect enhancement (PAE), and related smoking outcome expectancies were assessed in young individuals who reported smoking both marijuana and tobacco on a regular basis (dual users). More frequent smoking of a given substance was associated with expectations of greater NAR and PAE by that substance while duration of exposure did not reliably predict NAR or PAE drug expectancies. Contrary to expectations, individuals anticipating greater NAR and/or PAE for one substance did not exhibit corresponding expectancies for the other drug. These findings suggest that exposure duration may be less important than current usage levels in influencing affect expectancies and that the affect-related expectancies for tobacco and marijuana are largely independent of each other.

Human drug addiction is more than faulty decision-making

We commend Redish et al. for the progress they have made in bringing a measure of theoretical order to the processes that underlie drug addiction. However, incorporating information about situations in which drug users do not exhibit faulty decision-making into the theory would greatly enhance its generality and practical value. This commentary draws attention to the relevant human substance abuse literature.