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

The impact of alcohol on affiliative verbal behavior: A systematic review and meta-analysis

BACKGROUND

Language is a fundamental aspect of human social behavior that is linked to many rewarding social experiences, such as social bonding. Potential effects of alcohol on affiliative language may therefore be an essential feature of alcohol reward and may elucidate pathways through which alcohol is linked to social facilitation. Examinations of alcohol's impact on language content, however, are sparse. Accordingly, this investigation represents the first systematic review and meta-analysis of alcohol's effects on affiliative language. We test the hypothesis that alcohol increases affiliative verbal approach behaviors and discuss future research directions.

METHODS

PsycInfo and Web of Science were systematically searched in March 2023 according to our preregistered plan. Eligible studies included social alcohol administration experiments in which affiliative verbal language was assessed. We present a random-effects meta-analysis that examines the effect of alcohol compared to control on measures of affiliative verbal behavior.

RESULTS

Our search identified 16 distinct investigations (comprising 961 participants) that examined the effect of alcohol on affiliative verbal behavior. Studies varied greatly in methods and measures. Meta-analytic results demonstrated that alcohol is modestly associated with increases in affiliative verbal behavior (Hedges' g = 0.164, 95% CI [0.027, 0.301], p = 0.019). Study quality was rated using an adapted version of the Quality Assessment Tool for Quantitative Studies and did not significantly moderate alcohol's effects.

CONCLUSIONS

This study provides preliminary evidence that alcohol can increase affiliative verbal behaviors. This effect may be an important feature of alcohol reward. Given heterogeneity in study features, low study quality ratings, and limited reporting of effect size data, results simultaneously highlight the promise of this research area and the need for more work. Advances in language processing methodologies that could allow future work to systematically expand upon this finding are discussed.

Subjective intoxication predicts alcohol-related consequences at equivalent alcohol concentrations in young adults using ecological momentary assessment and alcohol sensors

OBJECTIVE

Subjective intoxication (SI) when drinking may serve as an internal barometer of whether to continue drinking or engage in potentially unsafe behavior. Mobile assessments offer the potential to use SI as a prospective risk indicator during drinking episodes; little evidence exists for the validity of real-time SI measures. We test the correspondence of SI with estimated blood alcohol concentration and transdermal alcohol concentration (TAC) in young adults' natural settings. We provide a novel test of whether SI features (peak and mean SI) uniquely predict consequences adjusting for alcohol concentration.

METHOD

Two hundred twenty-two heavy-drinking young adults (Mage = 22.3, 64% female, 79% non-Hispanic White, 84% undergraduates) participated in a 6-day study that used ecological momentary assessment of drinking and TAC sensors. SI was assessed every 30 min during drinking episodes. Multilevel modeling was used to test hypotheses.

RESULTS

Momentary SI and estimated blood alcohol concentration had moderate associations at the moment and day levels (standardized βs = 0.5-0.6); SI was moderately associated with TAC at the day level (βs = 0.5). Associations between SI and alcohol concentration varied widely between persons and across days. Day-level SI features predicted consequences when adjusting for alcohol concentration (incidence rate ratios, IRRs = 1.29-1.70).

CONCLUSIONS

Our two-item SI measure shows evidence of validity in real-world settings with heavy-drinking young adults. SI was significantly correlated with alcohol concentration and was a unique predictor of consequences. The strength of these associations varied greatly across persons and days. Real-time SI measurement may be useful in preventive interventions, but continued research is needed into when and for whom momentary SI is most predictive of risk. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Alcohol and common ground: The effects of intoxication on linguistic markers of shared understanding during social exchange

OBJECTIVE

Most alcohol consumption takes place in social contexts, and the belief that alcohol enhances social interactions has been identified as among the more robust predictors of alcohol use disorder (AUD) development. Yet, we know little of how alcohol affects mental representations of others-what we share and do not share-nor the extent to which intoxication might impact the development of shared understanding (i.e., common ground) between interaction partners. Employing a randomized experimental design and objective linguistic outcome measures, we present two studies examining the impact of alcohol consumption on the development and use of common ground.

METHOD

In Study 1, groups of strangers or friends were administered either alcohol (target Breath Alcohol Content = .08%) or a control beverage, following which they completed a task requiring them to develop a shared language to describe ambiguous images and then describe those images to either a knowledgeable or a naïve partner. The same procedures were completed in Study 2 using a within-subjects alcohol administration design and all-stranger groups.

RESULTS

Study 1 findings did not reach significance but suggested that alcohol may facilitate common ground development selectively among stranger groups. This effect emerged as significant in the context of the within-subjects design of Study 2, b = -0.19, p = .007, with participants demonstrating greater facility in establishing common ground during alcohol versus control sessions.

CONCLUSIONS

Results suggest that alcohol facilitates the development of shared linguistic understanding in novel social spaces, indicating common ground as one potential mechanism to consider in our broader examination of alcohol reinforcement and AUD etiology. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Associations Between Social Context and Mood During Alcohol Consumption in Young Adult Smokers

OBJECTIVE

Differences in the subjective effects of alcohol in different social contexts have been well documented, but little research examines affect during drinking in real-world social contexts. This study examined differences by social context in negative affect and positive affect during alcohol consumption. We hypothesized that negative affect and positive affect with drinking would vary as a function of social context (alone or with others).

METHOD

A total of 257 young adults (M age = 21.3, 53.3% female) who were enrolled in a longitudinal, observational study assessing risk for smoking completed 7 days of ecological momentary assessment assessing alcohol use, affect, and social context at two time points of the study. Mixed-effects location scale analyses examined effects of being alone versus with others on positive affect and negative affect after drinking and compared with nondrinking times.

RESULTS

Positive affect was higher when drinking with others versus alone, and negative affect was higher when drinking alone versus with others. Both negative affect and positive affect variability were higher when participants were drinking alone compared to with others, and negative affect variability was higher at low amounts of alcohol but decreased with increased drinking.

CONCLUSIONS

These findings demonstrate that solitary drinking is less consistently reinforcing because of greater and more variable negative affect, as well as more variable positive affect. When drinking with others, increased and less variable positive affect suggests that social drinking may be particularly reinforcing in young adulthood.

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.

Drinking context, alcohol use, and subjective responses during binge drinking episodes measured by high-resolution ecological momentary assessment (HR-EMA)

OBJECTIVE

Subjective responses to alcohol play a key role in the development and maintenance of risky drinking and alcohol use disorder (AUD). The social and environmental context where drinking occurs may moderate alcohol's subjective effects, but ecologically valid studies of these associations are limited. The present study used high-resolution ecological momentary assessment (HR-EMA) targeting real-world binge drinking episodes to examine associations among drinking context, alcohol consumption, and subjective responses to alcohol.

METHOD

Young adult heavy drinkers (N = 61; 57% male) completed two smartphone-based, 3-hr HR-EMA of drinking context (social context and location), alcohol use, and subjective responses (alcohol stimulation, sedation, feeling, liking, and wanting more). Analyses examined the associations between drinking context and subjective alcohol responses, accounting for demographic characteristics and individual differences in alcohol consumption.

RESULTS

Most (85%) participants reported binge drinking during real-world drinking events. Estimated blood alcohol concentration (eBAC) and alcohol stimulation and reward (liking, wanting) were greater when participants drank with others (vs. alone) and in a bar/restaurant (vs. other location). Sedation was higher when drinking alone versus with others.

CONCLUSIONS

The present study extends prior laboratory-based research and shows that subjective responses during naturalistic binge drinking episodes may be influenced by drinking context. Drinking with others and in bars and restaurants may increase alcohol consumption, enhance alcohol's rewarding effects, and lead to more alcohol-related harm in at-risk drinkers. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Interactive associations between abstinence plans and romantic partner conflict and support with cigarette smoking

BACKGROUND

While most individuals who smoke cigarettes desire to quit, quit motivation can change daily and sustained abstinence is rarely achieved in quit attempts. Assessment of psychosocial factors that moderate associations between daily abstinence intentions and smoking behavior is necessary to inform effective cessation efforts.

METHODS

A secondary analysis was conducted using data from a 28-day ecological momentary assessment study among individuals who smoke and who were not actively planning a long-term quit attempt (N = 81 individuals; N = 1585 days). We examined main effect and interaction associations between primary predictors (daily abstinence plans and within- and between-person estimates of perceived romantic relationship conflict and support) and daily number of cigarettes smoked, as well as baseline emotion regulation difficulties as a moderator of these associations.

RESULTS

Smoking was reduced on days with an abstinence plan (β=-0.57,p<.001), especially among individuals with lower average levels of conflict (plan × between-person conflict interaction: β=0.98, p < .001), and higher average levels of support (plan × between-person support interaction: β=0.26, p < .001). Additionally, smoking was increased on days when participants had higher levels of conflict than usual (β=0.07, p < .01), but only on days when participants did not have a plan (plan × within-person conflict interaction:β=-0.10, p < .05). Emotion regulation difficulties did not moderate any associations.

CONCLUSION

This study adds to the literature on the influence of negative aspects of social experience on smoking behavior. Further, the present study underlines the importance of assessing the influence of both positive and negative aspects of - and within- and between-person differences in - social experiences.

A strong alcoholic drink does not influence self-assessments of the big five personality traits

cAlohol affects how people think, feel, and behave, and how they perceive the physical and social world around them. But does alcohol also influence how people perceive themselves? Past work points to a number of possibilities, suggesting intoxication could lead to positive biases, to negative biases, or have no effects on self-assessments at all. Here we tested whether alcoholic intoxication affects self-assessments of personality within the Big Five personality framework. We hypothesized that intoxicated participants would see themselves more positively than non-intoxicated individuals would. We conducted a preregistered laboratory experiment on participants divided into three groups: alcohol intoxication (n = 106), placebo (n = 114), and control conditions (n = 109). Contrary to predictions, we found no differences in self-assessments of personality across conditions. Findings point to the possibility that self-assessments of personality may be too stable to be affected by the momentary changes in thoughts and feelings caused by alcoholic intoxication.

Meta-analysis of associations between empathy and alcohol use and problems in clinical and non-clinical samples

AIMS

To (1) measure the aggregated effect size of empathy deficits in individuals with alcohol use disorder (AUD) compared with healthy controls, (2) measure the aggregated effect sizes for associations between lower empathy and heavier alcohol consumption and more alcohol problems in non-clinical samples and (3) identify potential moderators on the variability of effect sizes across studies in these meta-analyses.

METHOD

PsycINFO, PubMed and Google Scholar were searched following a pre-registered International Prospective Register of Systematic Reviews (PROSPERO) protocol (CRD42021225392) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. We meta-analyzed (using random-effects models) mean differences in empathy between individuals with AUD compared with healthy controls and associations between empathy and alcohol consumption and alcohol problems in non-clinical samples. A total of 714 participants were included in the meta-analysis on clinical samples; 3955 were included in the meta-analyses on non-clinical samples.

RESULTS

Individuals with AUD reported significantly lower empathy than healthy controls [Hedges' g = -0.53, 95% confidence interval (CI) = -0.91, -0.16, k = 9, P < 0.01, Q = 40.09, I2  = 80.04]. Study quality [Q = 1.88, degrees of freedom (d.f.) = 1, P = 0.17] and gender (β = -0.006, Z = -0.60, P = 0.55) were not moderators. Increases in age corresponded to an increase in effect size (β = 0.095, Z = 3.34, P < 0.001). Individuals with AUD (versus healthy controls) had significantly lower cognitive (Hedges' g = -0.44, CI = -0.79, -0.10, P < 0.05), but not affective empathy (Hedges' g = -0.19, CI = -0.51, 0.14, P = 0.27), and the difference between these was significant (Z = 2.34, k = 6, P < 0.01). In non-clinical samples, individuals with lower (versus higher) empathy reported heavier alcohol consumption (r = -0.12, CI = -0.15, -0.09, k = 11, P < 0.001, Q = 9.68, I2  = 0.00) and more alcohol problems (r = -0.08, CI = -0.14, -0.01, k = 7, P = 0.021, Q = 6.55, I2  = 8.34). There was no significant heterogeneity across studies.

CONCLUSION

Individuals with alcohol use disorder appear to show deficits in empathy compared with healthy controls. Deficits are particularly pronounced for older individuals and for cognitive (versus affective) empathy. In non-clinical samples, lower empathy appears to be associated with heavier alcohol consumption and more alcohol problems.

Gabapentin increases the abuse liability of alcohol alone and in combination with oxycodone in participants with co-occurring opioid and alcohol use disorder

BACKGROUND

People who have co-occurring Alcohol Use Disorder (AUD) and Opioid Use Disorder (OUD) carry a higher risk of adverse outcomes, including drug overdose. Early clinical and preclinical studies suggested that gabapentin may be effective in treating both disorders. The present study was designed to assess the effects of gabapentin on the subjective and physiological effects of oxycodone (OXY) and alcohol (ALC), alone and in combination.

METHODS

During an 8-week, inpatient, within-subject, randomized, double-blind, placebo-controlled crossover study, non-treatment seeking participants (N = 13; 12 M/1F; 44.1 ± 3 years of age) with OUD and AUD were maintained on oral morphine (120 mg daily). Under gabapentin (1800 mg/day) and placebo (0 mg/day) maintenance, participants completed nine separate test sessions (three sessions per week) during which they received an oral solution containing 0, 15, or 30 mg/70 kg OXY in combination with 0, 0.5, or 0.75 g/kg ALC. During test sessions, subjective effects and physiological responses were assessed repeatedly on 100-mm visual analog scales (VAS). The primary outcome variable was the VAS rating of drug liking after receiving the drug challenge.

RESULTS

Alcohol alone (but not oxycodone alone) produced dose-related increases in several positive subjective responses, including drug liking. Gabapentin significantly increased drug liking when given in combination with ALC and OXY + ALC (p < 0.05). Gabapentin did not clinically compromise respiration or other vital functions.

CONCLUSIONS

Gabapentin may increase the abuse liability of ALC and OXY + ALC in those with co-occurring OUD and AUD.

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.

Drinking with Friends: Measuring the Two-week Ecology of Drinking Behaviors

Objectives: Despite the substantial influence these acute alcohol-related problems cause globally, past research has failed historically to capture the dynamic nature of drinking events, including how multiple factors (ie, individual, group, and environmental) interact to affect event-level intoxication. Fortunately, technology (eg, transdermal alcohol monitors) and smartphone surveys have provided researchers with new avenues to measure the complex nature of alcohol consumption. This paper presents the methods of a pilot study that sought to measure event-level alcohol consumption in a natural drinking group of college students. Methods: Ten groups of friends (N=49) were followed for 2 weeks with daily diary surveys, continuous activity trackers, hourly geographic ecological momentary assessments (EMAs) on 4 separate drinking occasions, and a transdermal alcohol monitor during one group-based social event. Results: On average, participants responded to > 75% of both daily diaries and EMAs and were compliant with activity trackers on 96% of monitoring days. Over 90% of the sample had usable transdermal data and after smoothing, peak transdermal alcohol contents ranged from 0.13 to 0.395 during the observation evening. Conclusion: The lessons learned during this pilot study can provide a building block for future work in this area, especially as data collection in alcohol research rapidly advances.

Prospective Effects of UPPS-P Impulsivity and Typical Drinking Context on Future Drinking Behavior

OBJECTIVE

Research suggests that impulsivity is a risk factor for problem drinking, but prior studies have yet to examine typical drinking context as a potential moderator of relations between impulsivity and drinking outcomes. Guided by Person-Environment Transactions Theory, the current study tested whether five facets of impulsivity (negative urgency, positive urgency, lack of premeditation, lack of perseverance, and sensation seeking) interacted with typical drinking context to prospectively predict drinking quantity.

METHOD

Young adult participants (N = 448; mean age = 22.27) were recruited from a southwestern university and the surrounding community. Data from a baseline survey (Time [T] 1) and a 1-year follow-up (T2) were used for the current analyses. Impulsivity (UPPS-P Impulsive Behavior Scale), typical drinking context, and typical drinking quantity were assessed at T1, and typical drinking quantity at T2.

RESULTS

Context items were loaded onto latent factors comprising high-arousal (e.g., at a tailgate, large house party) and low-arousal (e.g., at a restaurant, on a date) drinking contexts. In univariate (separated by UPPS-P facet) and multivariate (UPPS-P facets together) models, lack of premeditation and positive urgency interacted with high-arousal drinking contexts to predict T2 drinking, such that individuals at high/mean levels of impulsivity drank more heavily the more frequently they drank in high-arousal contexts. Only interactions in univariate models remained significant after a false discovery correction, although effect sizes were very similar across univariate and multivariate models.

CONCLUSIONS

Individuals high in positive urgency and lack of premeditation may be particularly vulnerable to riskier drinking behavior in high-arousal environments. Findings advance the literature on context-specific cues that may be important intervention targets, particularly for individuals high in positive urgency and lack of premeditation.

Prospective Effects of UPPS-P Impulsivity and Typical Drinking Context on Future Drinking Behavior

OBJECTIVE

Research suggests that impulsivity is a risk factor for problem drinking, but prior studies have yet to examine typical drinking context as a potential moderator of relations between impulsivity and drinking outcomes. Guided by Person-Environment Transactions Theory, the current study tested whether five facets of impulsivity (negative urgency, positive urgency, lack of premeditation, lack of perseverance, and sensation seeking) interacted with typical drinking context to prospectively predict drinking quantity.

METHOD

Young adult participants (N = 448; mean age = 22.27) were recruited from a southwestern university and the surrounding community. Data from a baseline survey (Time [T] 1) and a 1-year follow-up (T2) were used for the current analyses. Impulsivity (UPPS-P Impulsive Behavior Scale), typical drinking context, and typical drinking quantity were assessed at T1, and typical drinking quantity at T2.

RESULTS

Context items were loaded onto latent factors comprising high-arousal (e.g., at a tailgate, large house party) and low-arousal (e.g., at a restaurant, on a date) drinking contexts. In univariate (separated by UPPS-P facet) and multivariate (UPPS-P facets together) models, lack of premeditation and positive urgency interacted with high-arousal drinking contexts to predict T2 drinking, such that individuals at high/mean levels of impulsivity drank more heavily the more frequently they drank in high-arousal contexts. Only interactions in univariate models remained significant after a false discovery correction, although effect sizes were very similar across univariate and multivariate models.

CONCLUSIONS

Individuals high in positive urgency and lack of premeditation may be particularly vulnerable to riskier drinking behavior in high-arousal environments. Findings advance the literature on context-specific cues that may be important intervention targets, particularly for individuals high in positive urgency and lack of premeditation.

Alcohol and Placebo: The Role of Expectations and Social Influence

The placebo effect is frequently present in our lives when an expectation, associated with any psychoactive material, leads to subjective and physiological changes. The present work studies the role of expectancies associated with ethanol/alcohol in changes to the subjective state. In experimental situations, we examine how these expectations—with or without social influences—affect participants when consuming alcoholic, pseudo-alcoholic, or non-alcoholic cocktails. Psychological and physical changes can, to a significant extent, arise from an expectation-driven placebo effect. We suggest that expectations of inebriation formed by socialization and experiences can explain most of the behavioural changes following alcohol consumption. These effects seem to be stronger if the alcohol consumption happens in a social context and weaker if it is individually. Regarding the information effect, we suppose that the expectations will positively affect the drunkenness, i.e. toward the placebo “direction”: those who believe they are consuming a non-alcoholic cocktail will be less inebriated than those who know their drink contains alcohol. In this study, we successfully demonstrate the expectation-induced classical placebo effect in the misinformed participants who were, in fact, consuming non-alcoholic drinks. The “social” alcohol consumption further enhances the true or believed effects of the alcohol, and thus the participants reported their subjective feelings in lines with their manipulated expectations. As regards the effect of the alcohol, therefore, many other factors contribute in addition to the alcohol itself, the most important of which seem to be group effect, suggestions and expectations.

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.

Ventral striatum regulates behavioral response to ethanol and MDMA combination

Our previous studies consistently showed that MDMA-induced locomotor hyperactivity is dramatically increased by coadministration of ethanol (EtOH) in rats, indicating possible potentiation of MDMA abuse liability. Thus, we aimed to identify the brain region(s) and neuropharmacological substrates involved in the pharmacodynamics of this potentiation. We first showed that potentiation of locomotor activity by the combination of ip administration of EtOH (1.5 g/kg) and MDMA (6.6 mg/kg) is delay sensitive and maximal when both drugs are injected simultaneously. Then, we used the 2-deoxyglucose quantitative autoradiography technique to assess the impact of EtOH, MDMA, or their combination on local cerebral metabolic rates for glucose (CMRglcs). We showed a specific metabolic activation in the ventral striatum (VS) under MDMA + EtOH versus MDMA or EtOH alone. We next tested if reversible (tetrodotoxin, TTX) or permanent (6-hydrodoxyopamine, 6-OHDA) lesion of the VS could affect locomotor response to MDMA and MDMA + EtOH. Finally, we blocked dopamine D1 or glutamate NMDA receptors in the VS and measured the effects of MDMA and MDMA + EtOH on locomotor activity. We showed that bilateral reversible inactivation (TTX) or permanent lesion (6-OHDA) of the VS prevented the potentiation by EtOH of MDMA-induced locomotor hyperactivity. Likewise, blockade of D1 or NMDA receptors in the VS also reduced the potentiation of MDMA locomotor activity by EtOH. These data indicate that dopamine D1 and glutamate NMDA receptor-driven mechanisms in the VS play a key role in the pharmacodynamics of EtOH-induced potentiation of the locomotor effects of MDMA.

Acute administration of oxycodone, alcohol, and their combination on simulated driving-preliminary outcomes in healthy adults

RATIONALE

Epidemiological data indicate that drivers testing positive for an opioid drug are twice as likely to cause a fatal car crash; however, there are limited controlled data available.

OBJECTIVES

The primary aim of this study was to assess the effects of a therapeutic dose range of oxycodone alone and in combination with alcohol on simulated driving performance.

METHODS

Healthy participants (n = 10) completed this within-subject, double-blind, placebo-controlled, randomized outpatient study. Six 7-h sessions were completed during which oxycodone (0, 5, 10 mg, p.o.) was administered 30 min before alcohol (0, 0.8 g/kg (15% less for women), p.o.) for a total of 6 test conditions. Driving assessments and participant-, observer-rated, psychomotor and physiological measures were collected in regular intervals before and after drug administration.

RESULTS

Oxycodone alone (5, 10 mg) did not produce any changes in driving outcomes or psychomotor task performance, relative to placebo (p > 0.05); however, 10 mg oxycodone produced increases in an array of subjective ratings, including sedation and impairment (p < 0.05). Alcohol alone produced driving impairment (e.g., decreased lateral control) (p < 0.05); however, oxycodone did not potentiate alcohol-related driving or subjective effects.

CONCLUSIONS

These preliminary data suggest that acute doses of oxycodone (5, 10 mg) do not significantly impair acuity on laboratory-based simulated driving models; however, 10 mg oxycodone produced increases in self-reported outcomes that are not compatible with safe driving behavior (e.g., sedation, impairment). Additional controlled research is needed to determine how opioid misuse (higher doses; parenteral routes of administration) impacts driving risk.

Psychostimulant use disorder emphasizing methamphetamine and the opioid -dopamine connection: Digging out of a hypodopaminergic ditch

BACKGROUND

Approved food and drug administration (FDA) medications to treat Psychostimulant Use Disorder (PUD) are needed. Both acute and chronic neurological deficits related to the neurophysiological effects of these powerfully addictive drugs can cause stroke and alterations in mood and cognition.

OBJECTIVE

This article presents a brief review of the psychiatric and neurobiological sequelae of methamphetamine use disorder, some known neurogenetic associations impacted by psychostimulants, and explores treatment modalities and outcomes.

HYPOTHESIS

The authors propose that gentle D2 receptor stimulation accomplished via some treatment modalities can induce dopamine release, causing alteration of D2-directed mRNA and thus enhanced function of D2 receptors in the human. This proliferation of D2 receptors, in turn, will induce the attenuation of craving behavior, especially in genetically compromised high-risk populations.

DISCUSSION

A better understanding of the involvement of molecular neurogenetic opioid, mesolimbic dopamine, and psychostimulant connections in "wanting" supports this hypothesis. While both scientific and, clinical professionals search for an FDA approved treatment for PUD the induction of dopamine homeostasis, via activation of the brain reward circuitry, offers treatment for underlying neurotransmitter functional deficits, potential prophylaxis, and support for recovery efforts.

CONCLUSION

Dopamine regulation may help people dig out of their hypodopaminergia ditch.

Neural activation during anticipation of monetary gain or loss does not associate with positive subjective response to alcohol in binge drinkers

BACKGROUND

Alcohol use disorder (AUD) remains an unresolved source of morbidity and mortality. Psychopharmacological challenge studies and neuroimaging experiments are two methods used to identify risk of problematic substance use. The present study combined these two approaches by examining associations between self-reported stimulation, sedation, liking or wanting more after a dose of alcohol and neural-based responses to anticipation of monetary gain and loss.

METHODS

Young adult binge drinkers (N = 56) aged 21-29, with no history of Substance Use Disorder completed five experimental sessions. These included four laboratory sessions in which they rated their subjective responses to alcohol (0.8 g/kg for men, 0.68 g/kg for women) or placebo, and a single functional magnetic resonance imaging session in which they completed a monetary incentive delay task. During the scan, we recorded neural signal related to anticipation of winning $5 or $1.50 compared to winning no money (WinMoney-WinZero), losing $5 or $1.50 compared to losing no money (LoseMoney-LoseZero), and winning $5 or $1.50 compared to losing $5 or $1.50 (WinMoney-LoseMoney), in reward related regions.

RESULTS

There were no significant associations between subjective ratings of "Feel Drug Effect", "Like Drug Effect", "Want More", stimulation or sedation following the acute alcohol challenge and neural activation in reward related regions during anticipation of monetary gain or loss.

CONCLUSIONS

These results suggest that sensitivity of neural reward circuits is not directly related to rewarding subjective experiences from alcohol. Taken together with previous studies, the present findings indicate that the association between the subjective effects of drugs and reward-related brain activity depends on the drugs, tasks or subject samples under study.

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.

Subjective Effects of Alcohol Predict Alcohol Choice in Social Drinkers

INTRODUCTION

Alcohol is among the most commonly used psychoactive drugs, yet it can produce markedly different subjective effects in different people. Certain effects, including both heightened stimulatory effects and lesser sedative effects, are thought to predict repeated or excessive use. However, we do not fully understand the nature of these individual differences or their relationships to alcohol consumption. This controlled laboratory study examined subjective and physiologic responses to a moderate dose of alcohol in social drinkers in relation to the subjects' decision to consume alcohol.

METHODS

Healthy adult volunteers (N = 95) participated in a 5-session double-blind alcohol choice study. On the first 4 sessions, they received alcohol (0.8 g/kg) and placebo in alternating order, and on the fifth session, they chose and consumed whichever of the 2 they preferred. During each session, participants completed the Profile of Mood States (POMS) and Biphasic Alcohol Effects Scale (BAES) questionnaires and had their vitals recorded every 30 minutes. We compared subjective and physiologic response to alcohol during the sampling sessions in participants who chose alcohol or placebo on session 5.

RESULTS

Of the 95 participants, 55 chose alcohol (choosers) and 40 chose placebo (nonchoosers). In the full sample, alcohol produced its expected effects (e.g., increased friendliness, elation, and vigor (POMS), and stimulation and sedation (BAES)). The chooser and nonchooser groups did not differ in demographic characteristics, blood alcohol levels, or cardiovascular measures. However, the choosers experienced greater alcohol-induced increases in positive mood (POMS) and liked the drug more, whereas the nonchoosers experienced greater anger, anxiety (POMS), and sedation (BAES) after alcohol.

CONCLUSION

Both greater positive mood effects and lesser sedative effects after alcohol predicted preference under controlled conditions, suggesting that both factors can predict future consumption of alcohol.

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.

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).

Conceptualizing Health Behaviors as Acute Mood-Altering Agents: Implications for Cancer Control

A massive portion of cancer burden is accounted for by a small collection of highly prevalent cancer risk behaviors (e.g., low physical activity, unhealthy diet, and tobacco use). Why people engage in numerous types of cancer risk behaviors and fail to adopt various cancer prevention behaviors has been poorly understood. In this commentary, we propose a novel scientific framework, which argues that a common affective (i.e., emotion based) mechanism underpins a diversity of such cancer risk and prevention behaviors. The scientific premise is that cancer risk and prevention behaviors produce immediate and robust changes in affective states that are translated into motivations and drives, which promote further pursuit of risk behaviors or avoidance of prevention behaviors. After describing the conceptual and scientific basis for this framework, we then propose central research questions that can address the validity and utility of the framework. Next, we selectively review and integrate findings on the mood-altering effects of various cancer risk and prevention behaviors from the addiction science, exercise science, and behavioral nutrition literatures, focusing on the nature and phenomenology of behavior-elicited mood changes and their value for predicting future behavior change. We conclude by discussing how this framework can be applied to address critical scientific questions in cancer control.

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 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

A review of the effects of nicotine on social functioning

Many smokers are aware that smoking is a dangerous health behavior and eventually try to quit smoking. Unfortunately, most quit attempts end in failure. Traditionally, the addictive nature of smoking has been attributed to the pharmacologic effects of nicotine. In an effort to offer a more comprehensive, biobehavioral analysis of smoking behavior and motivation, some researchers have begun to consider the role of social factors in smoking. In line with recent recommendations to integrate social and pharmacological analyses of smoking, we reviewed the experimental literature examining the effects of nicotine and nicotine withdrawal on social functioning. The review identified 13 studies that experimentally manipulated nicotine and assessed social functioning, 12 of which found support for nicotine's enhancement of social functioning. Although few experiments have investigated social functioning, they nevertheless offer compelling evidence that nicotine enhances social functioning in smokers and suggest that nicotine deprivation may hamper social functioning in those dependent on nicotine. Future directions for investigating social outcomes and context in those who use nicotine products are discussed with a focus on leveraging advances in social and developmental psychology, animal research, sociology, and neuroimaging to more comprehensively understand smoking behavior. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Sex Differences in Motivation to Self-Administer Alcohol After 2 Weeks of Abstinence in Young-Adult Heavy Drinkers

BACKGROUND

Studies in animal models document that forced abstinence from usual consumption of alcohol changes subsequent seeking and consumption, with increases or decreases depending on the species, duration of abstinence, number of deprivations, and sex. Human laboratory-based alcohol deprivation studies are rare.

METHODS

We conducted a 2-session, within-participant, randomized-order comparison of intravenous, progressive ratio, alcohol self-administration during 2.5 hours of progressive work for alcohol and/or vehicle; once while the participants pursued their usual drinking habits and once after 2 weeks of closely monitored, voluntary outpatient abstinence from alcohol. The schedule of work for rewards and the incremental increases in breath alcohol concentration following completion of an alcohol work-set were identical across participants. Fifty young-adult (27 men), heavy-drinking participants completed both sessions. Our primary hypothesis was that motivation to work for alcohol after 2 weeks of abstinence would be greater in participants with a weekly binge pattern of drinking, compared to those who regularly drink heavily, and we intended to explore associations with biological family history of alcoholism and sex.

RESULTS

We detected no change in work for alcohol associated with recent drinking history. However, females, on average, increased their work for alcohol upon resumption after 2 weeks of abstinence (mean ± SEM = +16.3 ± 9.6%), while males decreased that work (-24.8 ± 13.8%). The sex difference was substantial and significant (p < 0.03), with a medium effect size (Cohen's d = 0.63).

CONCLUSIONS

We believe a more comprehensive study of mechanisms underlying the sex differences in the human postabstinence response is warranted.

Using Placebo Beverages in Group Alcohol Studies

BACKGROUND

Placebo beverage conditions remain a key element in the methodological toolkit for alcohol researchers interested in evaluating pharmacological and nonpharmacological factors influencing the effects of alcohol consumption. While interest in experimentally examining alcohol in social context is on the rise, there has been little research examining the effectiveness of placebo manipulations in group settings, when just 1 suspicious participant could potentially jeopardize the effect of the placebo on group members. Moreover, research has rarely considered the association between individual difference factors (e.g., gender) and placebo manipulation effectiveness. The present study, using an uncommonly large sample of placebo-consuming participants, was well suited to investigate fundamental questions regarding placebo efficacy that have not been assessed previously. Specifically, we aimed to examine placebo efficacy and general processes of placebo functioning in a group context. We also assessed potential associations between a variety of individual difference factors and placebo response.

METHODS

A total of 240 participants (50% male) consumed placebo beverages during a triadic drinking period (across 80 three-person groups). Participants reported their subjective intoxication, stimulation, and sedation 8 minutes following drink consumption and estimated the alcohol content of their drink at the end of the study.

RESULTS

Participants consuming placebo beverages in groups were nearly universal in reporting that they had consumed alcohol (>99%) and had experienced an increase in feelings of intoxication [t(239) = 22.03, p < 0.001] and stimulation [t(239) = 5.53, p < 0.001], levels that were similar to those observed in prior studies conducted with participants drinking placebos in isolation. Further, participants' placebo responses were independent of their 2 group members and were largely unaffected by a variety of individual difference factors.

CONCLUSIONS

Placebo response generally operated independently of group-member influences, suggesting that researchers can successfully conduct placebo beverage studies utilizing group drinking designs.

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.

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.

Acute alcohol effects on facial expressions of emotions in social drinkers: a systematic review

Background

As known from everyday experience and experimental research, alcohol modulates emotions. Particularly regarding social interaction, the effects of alcohol on the facial expression of emotion might be of relevance. However, these effects have not been systematically studied. We performed a systematic review on acute alcohol effects on social drinkers' facial expressions of induced positive and negative emotions.

Materials and methods

With a predefined algorithm, we searched three electronic databases (PubMed, PsycInfo, and Web of Science) for studies conducted on social drinkers that used acute alcohol administration, emotion induction, and standardized methods to record facial expressions. We excluded those studies that failed common quality standards, and finally selected 13 investigations for this review.

Results

Overall, alcohol exerted effects on facial expressions of emotions in social drinkers. These effects were not generally disinhibiting, but varied depending on the valence of emotion and on social interaction. Being consumed within social groups, alcohol mostly influenced facial expressions of emotions in a socially desirable way, thus underscoring the view of alcohol as social lubricant. However, methodical differences regarding alcohol administration between the studies complicated comparability.

Conclusion

Our review highlighted the relevance of emotional valence and social-context factors for acute alcohol effects on social drinkers' facial expressions of emotions. Future research should investigate how these alcohol effects influence the development of problematic drinking behavior in social drinkers.

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 effects of MDMA on socio-emotional processing: Does MDMA differ from other stimulants?

±3,4-Methylenedioxymethamphetamine (MDMA) is a popular recreational drug that enhances sociability and feelings of closeness with others. These "prosocial" effects appear to motivate the recreational use of MDMA and may also form the basis of its potential as an adjunct to psychotherapy. However, the extent to which MDMA differs from prototypic stimulant drugs, such as dextroamphetamine, methamphetamine, and methylphenidate, in either its behavioral effects or mechanisms of action, is not fully known. The purpose of this review is to evaluate human laboratory findings of the social effects of MDMA compared to other stimulants, ranging from simple subjective ratings of sociability to more complex elements of social processing and behavior. We also review the neurochemical mechanisms by which these drugs may impact sociability. Together, the findings reviewed here lay the groundwork for better understanding the socially enhancing effects of MDMA that distinguish it from other stimulant drugs, especially as these effects relate to the reinforcing and potentially therapeutic effects of the drug.

Sweetened ethanol drinking during social isolation: enhanced intake, resistance to genetic heterogeneity and the emergence of a distinctive drinking pattern in adolescent mice

With its ease of availability during adolescence, sweetened ethanol ('alcopops') is consumed within many contexts. We asked here whether genetically based differences in social motivation are associated with how the adolescent social environment impacts voluntary ethanol intake. Mice with previously described differences in sociability (BALB/cJ, C57BL/6J, FVB/NJ and MSM/MsJ strains) were weaned into isolation or same-sex pairs (postnatal day, PD, 21), and then given continuous access to two fluids on PDs 34-45: one containing water and the other containing an ascending series of saccharin-sweetened ethanol (3-6-10%). Prior to the introduction of ethanol (PDs 30-33), increased water and food intake was detected in some of the isolation-reared groups, and controls indicated that isolated mice also consumed more 'saccharin-only' solution. Voluntary drinking of 'ethanol-only' was also higher in a subset of the isolated groups on PDs 46-49. However, sweetened ethanol intake was increased in all isolated strain × sex combinations irrespective of genotype. Surprisingly, blood ethanol concentration (BEC) was not different between these isolate and socially housed groups 4 h into the dark phase. Using lickometer-based measures of intake in FVB mice, we identified that a predominance of increased drinking during isolation transpired outside of the typical circadian consumption peak, occurring ≈8.5 h into the dark phase, with an associated difference in BEC. These findings collectively indicate that isolate housing leads to increased consumption of rewarding substances in adolescent mice independent of their genotype, and that for ethanol this may be because of when individuals drink during the circadian cycle.

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.

A Moderate Dose of Alcohol Does Not Influence Experience of Social Ostracism in Hazardous Drinkers

Anecdotal and correlational evidence suggests a relationship between social ostracism and alcohol dependence. Furthermore, a recent fMRI investigation found differences in the neural correlates associated with ostracism in people with alcohol dependence compared to healthy controls. We predicted that acutely administered alcohol would reduce the negative effects of social ostracism. Alcohol (0.4 g/kg) or matched placebo was administered to a sample of 32 hazardous drinkers over two sessions in a randomized, double-blind, cross-over design. In each session, participants were exposed to an ostracism event via the computerized ball passing game, "Cyberball." In order to quantify the effects of ostracism, the fundamental needs questionnaire was completed twice on each testing session; immediately after (i) social inclusion and (ii) social exclusion. Ostracism caused robust changes to scores on the fundamental needs questionnaire, in line with previous literature. Alcohol administration did not influence the effects of simulated social ostracism, which was supported by a Bayesian analysis. Exploratory analyses revealed a negative relationship between age and ostracism induced fundamental needs threat across both sessions. In conclusion, a moderate dose of alcohol did not influence experience of simulated social ostracism in hazardous drinkers. Further research is needed to establish the effects of alcohol administration on social ostracism using different doses and populations of alcohol users.

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.

Effects of acute doses of prosocial drugs methamphetamine and alcohol on plasma oxytocin levels

Many drugs, including alcohol and stimulants, demonstrably increase sociability and verbal interaction and are recreationally consumed in social settings. One drug, 3,4-methylenedioxymethamphetamine (MDMA, ecstasy), seems to produce its prosocial effects by increasing plasma oxytocin levels, and the oxytocin system has been implicated in responses to several other drugs of abuse. Here, we sought to investigate the effects of 2 other "social" drugs on plasma oxytocin levels--methamphetamine and alcohol. Based on their shared capacity to enhance sociability, we hypothesized that both methamphetamine and alcohol would increase plasma oxytocin levels. In study 1, 11 healthy adult volunteers attended 3 sessions during which they received methamphetamine (10 mg or 20 mg) or placebo under double-blind conditions. Subjective drug effects, cardiovascular effects, and plasma oxytocin levels were measured at regular intervals throughout the sessions. In study 2, 8 healthy adult volunteers attended a single session during which they received 1 beverage containing placebo, and then a beverage containing alcohol (0.8 g/kg). Subjective effects, breath alcohol levels, and plasma oxytocin levels were measured at regular intervals. Both methamphetamine and alcohol produced their expected physiological and subjective effects, but neither of these drugs increased plasma oxytocin levels. The neurobiological mechanisms mediating the prosocial effects of drugs such as alcohol and methamphetamine remain to be identified.