Alcohol narrows physical distance between strangers.

Pandemic management is likely to represent a global reality for years to come, but the roadmap for how to approach pandemic restrictions is as yet unclear. Of the restrictions enacted during COVID-19, among the more controversial surround alcohol. Like many infectious diseases, the principal mode of transmission for COVID-19 is direct respiration of droplets emitted during close social contact, and health officials warn that alcohol consumption may lead to decreased adherence to physical distancing guidelines. Governing bodies have acted to close bars before restaurants and have also specifically restricted alcohol sales, while at the same time those in the nightlife industry have labeled such actions unfounded and discriminatory. Complicating such debates is the lack of evidence on alcohol's effects on physical distance. In the current study we employed a randomized alcohol-administration design paired with computer-vision measures, analyzing over 20,000 proximity readings derived from video to examine the effect of alcohol consumption on physical distance during social interaction. Results indicated that alcohol caused individuals to draw significantly closer to an unfamiliar interaction partner during social exchange, reducing physical proximity at a rate with potentially important implications for public health. In contrast, alcohol had no effect on physical distance with a familiar interaction partner. Findings suggest that alcohol might act to overcome a natural caution people feel towards strangers and thus promote virus transmission between previously unconnected social groups.

Temporal Dynamics of Transdermal Alcohol Concentration Measured via New-Generation Wrist-Worn Biosensor.

BACKGROUND: The development of a transdermal alcohol biosensor could represent a tremendous advance toward curbing problematic drinking. But several factors limit the usefulness of extant transdermal technology, including relatively lengthy delays between blood alcohol concentration (BAC) and transdermal alcohol concentration (TAC), as well as the large/bulky designs of currently available transdermal sensors (e.g., ankle monitors). The current research examined the lag time between BAC and TAC using a prototype of BACtrack Skyn-a new-generation wrist-worn transdermal sensor featuring a compact design and smartphone integration. METHODS: Participants (N = 30) received either a dose of alcohol (target BAC 0.08%) or a nonalcoholic beverage in the laboratory while wearing both the AMS SCRAM ankle monitor and a Skyn prototype. Participants were monitored in the laboratory until breath alcohol concentration (BrAC) dropped below 0.025%. RESULTS: Device failure rates for Skyn prototypes were relatively high (18 to 38%) compared with nonprototype SCRAM devices (2%). Among participants with usable data, both Skyn- and SCRAM-measured TAC showed strong correlations with BrAC, and both Skyn and SCRAM devices detected alcohol within 30 minutes of first alcohol administration. Skyn-measured TAC peaked over 1 hour earlier than SCRAM-measured TAC (54 versus 120 minutes after peak BrAC, respectively), and time-series models suggested that, on average across all measured portions of the BrAC curve, Skyn TAC lagged behind BrAC by 24 minutes, whereas SCRAM TAC lagged behind BrAC by 69 minutes-all differences statistically significant at p < 0.001. CONCLUSIONS: Results provide preliminary evidence for the validity of a new-generation wrist-worn transdermal sensor under controlled laboratory conditions and further suggest favorable properties of this sensor as they pertain to the latency of transdermal alcohol detection. The prototype version of Skyn employed here displayed a higher failure rate compared with SCRAM, and, in future, more reliable and robust Skyn prototypes will be required suitable to field testing across diverse environmental conditions.

Estimating the Distribution of Random Parameters in a Diffusion Equation Forward Model for a Transdermal Alcohol Biosensor.

We estimate the distribution of random parameters in a distributed parameter model with unbounded input and output for the transdermal transport of ethanol in humans. The model takes the form of a diffusion equation with the input being the blood alcohol concentration and the output being the transdermal alcohol concentration. Our approach is based on the idea of reformulating the underlying dynamical system in such a way that the random parameters are now treated as additional space variables. When the distribution to be estimated is assumed to be defined in terms of a joint density, estimating the distribution is equivalent to estimating the diffusivity in a multi-dimensional diffusion equation and thus well-established finite dimensional approximation schemes, functional analytic based convergence arguments, optimization techniques, and computational methods may all be employed. We use our technique to estimate a bivariate normal distribution based on data for multiple drinking episodes from a single subject.

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.

Deconvolving the input to random abstract parabolic systems: a population model-based approach to estimating blood/breath alcohol concentration from transdermal alcohol biosensor data.

The distribution of random parameters in, and the input signal to, a distributed parameter model with unbounded input and output operators for the transdermal transport of ethanol are estimated. The model takes the form of a diffusion equation with the input, which is on the boundary of the domain, being the blood or breath alcohol concentration (BAC/BrAC), and the output, also on the boundary, being the transdermal alcohol concentration (TAC). Our approach is based on the reformulation of the underlying dynamical system in such a way that the random parameters are treated as additional spatial variables. When the distribution to be estimated is assumed to be defined in terms of a joint density, estimating the distribution is equivalent to estimating a functional diffusivity in a multi-dimensional diffusion equation. The resulting system is referred to as a population model, and well-established finite dimensional approximation schemes, functional analytic based convergence arguments, optimization techniques, and computational methods can be used to fit it to population data and to analyze the resulting fit. Once the forward population model has been identified or trained based on a sample from the population, the resulting distribution can then be used to deconvolve the BAC/BrAC input signal from the biosensor observed TAC output signal formulated as either a quadratic programming or linear quadratic tracking problem. In addition, our approach allows for the direct computation of corresponding credible bands without simulation. We use our technique to estimate bivariate normal distributions and deconvolve BAC/BrAC from TAC based on data from a population that consists of multiple drinking episodes from a single subject and a population consisting of single drinking episodes from multiple subjects.

Non-alcoholic beverage consumption among US adults who consume alcohol.

BACKGROUND AND AIMS: Non-alcoholic beverages (NABs) that mimic alcohol without inducing intoxication, such as non-alcoholic beers, non-alcoholic wines and spirit-free drinks, are increasing in popularity. It is unknown whether NABs help to mitigate or stimulate alcohol use. The present study aimed to describe NAB consumption practices among US adults consuming alcohol, characterize who is likely to consume NABs and examine whether NAB use influences desire for and perceived consumption of alcohol. DESIGN AND PARTICIPANTS: The survey study used data collected June-July 2023 from an on-line convenience sample. The first survey (n = 1906) assessed frequency of NAB consumption among US adults who consume alcohol. A second more detailed survey on use patterns was conducted with 466 respondents who reported past-year NAB consumption, of whom 153 (32.83%) screened positive on the CAGE questionnaire for alcohol use disorder (AUD). SETTING: This study took place in the United States. MEASUREMENTS: NAB consumption measures included type of NAB consumed, frequency, quantity, first consumption age, consumption reasons, consumption contexts and perceived effect on desire for and consumption of alcohol. Alcohol use measures included frequency, quantity and first consumption age. FINDINGS: Past-year NAB use was endorsed by 28.44% of respondents (61.70% ever used). Non-alcoholic liquor/'mocktails' were the most common NAB type consumed (83.69%). Compared with respondents without AUD, those who screened positive for AUD were significantly more likely to consume NABs in an effort to decrease or abstain from drinking alcohol [adjusted odds ratio (AOR) = 3.54, 95% confidence interval (CI) = 2.24-5.58] and 67.97% endorsed less alcohol consumption (3.23% endorsed more) due to their NAB use. NAB consumption frequency and quantity were significantly positively predicted by alcohol consumption frequency (AOR = 1.46, 95% CI = 1.17-1.83) and quantity (ß = 0.25, 95% CI = 0.15-0.35), respectively. CONCLUSION: Adults who consume alcohol and screen positive for alcohol use disorder report drinking non-alcoholic beverages as a harm reduction strategy.

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).

Examining new-generation transdermal alcohol biosensor performance across laboratory and field contexts.

BACKGROUND: Wrist-worn transdermal alcohol sensors have the potential to change how alcohol consumption is measured. However, hardware and data analytic challenges associated with transdermal sensor data have kept these devices from widespread use. Given recent technological and analytic advances, this study provides an updated account of the performance of a new-generation wrist-worn transdermal sensor in both laboratory and field settings. METHODS: This work leverages machine learning models to convert transdermal alcohol concentration data into estimates of Breath Alcohol Concentration (BrAC) in a large-scale laboratory sample (N = 256, study 1) and a pilot field sample (N = 27, study 2). Specifically, in both studies, the accuracy of the translation is evaluated by comparing BAC estimates yielded by BACtrack Skyn to real-time breathalyzer measurements collected in the laboratory and in the field. RESULTS: The newest version of the Skyn device demonstrates a substantially lower error rate than older hand-assembled prototypes (0% to 7% vs. 29% to 53%, respectively). On average, real-time estimates of BrAC yielded by these transdermal sensors are within 0.007 of true BAC readings in the laboratory context and within 0.019 of true BrAC readings in the field. In both contexts, the distance between true and estimated BrAC was larger when only alcohol episodes were examined (laboratory = 0.017; field = 0.041). Finally, results of power-law-curve projections indicate that, given their accuracy, transdermal BrAC estimates in real-world contexts have the potential to improve markedly (>25%) with adequately sized datasets for model training. CONCLUSION: Findings from this study indicate that the latest version of the transdermal wrist sensor holds promise for the accurate assessment of alcohol consumption in field contexts. A great deal of additional work is needed to provide a full picture of the utility of these devices, including research with large participant samples in field contexts.

Where to Look? Alcohol, Affect, and Gaze Behavior During a Virtual Social Interaction.

COVID-19 forced social interactions to move online. Yet researchers have little understanding of the mental health consequences of this shift. Given pandemic-related surges in emotional disorders and problematic drinking, it becomes imperative to understand the cognitive and affective processes involved in virtual interactions and the impact of alcohol in virtual social spaces. Participants (N=246) engaged in an online video call while their gaze behavior was tracked. Prior to the interaction, participants were randomly assigned to receive an alcoholic or control beverage. Participants' affect was repeatedly assessed. Results indicated that a proportionally larger amount of time spent gazing at oneself (vs. one's interaction partner) predicted significantly higher negative affect after the exchange. Further, alcohol independently increased self-directed attention, failing to demonstrate its typically potent social-affective enhancement in this virtual context. Results carry potential implications for understanding factors that increase risk for hazardous drinking and negative affect in our increasingly virtual world.

Social anxiety and alcohol consumption: The role of social context.

Research has identified social anxiety as a risk factor for the development of alcohol use disorder. However, studies have produced equivocal findings regarding the relationship between social anxiety and drinking behaviors in authentic drinking environments. This study examined how social-contextual features of real-world drinking contexts might influence the relationship between social anxiety and alcohol consumption in everyday settings. At an initial laboratory visit, heavy social drinkers (N = 48) completed the Liebowitz Social Anxiety Scale. Participants were then outfitted with a transdermal alcohol monitor individually-calibrated for each participant via laboratory alcohol-administration. Over the next seven days, participants wore this transdermal alcohol monitor and responded to random survey prompts (6x/day), during which they provided photographs of their surroundings. Participants then reported on their levels of social familiarity with individuals visible in photographs. Multilevel models indicated a significant interaction between social anxiety and social familiarity in predicting drinking, b = -0.004, p =.003 Specifically, among participants higher in social anxiety, drinking increased as social familiarity decreased b = -0.152, p <.001, whereas among those lower in social anxiety, this relationship was non-significant, b = 0.007, p =.867. Considered alongside prior research, findings suggest that the presence of strangers within a given environment may play a role in the drinking behavior of socially anxious individuals.

Alcohol and group formation: a multimodal investigation of the effects of alcohol on emotion and social bonding.

We integrated research on emotion and on small groups to address a fundamental and enduring question facing alcohol researchers: What are the specific mechanisms that underlie the reinforcing effects of drinking? In one of the largest alcohol-administration studies yet conducted, we employed a novel group-formation paradigm to evaluate the socioemotional effects of alcohol. Seven hundred twenty social drinkers (360 male, 360 female) were assembled into groups of 3 unacquainted persons each and given a moderate dose of an alcoholic, placebo, or control beverage, which they consumed over 36 min. These groups' social interactions were video recorded, and the duration and sequence of interaction partners' facial and speech behaviors were systematically coded (e.g., using the facial action coding system). Alcohol consumption enhanced individual- and group-level behaviors associated with positive affect, reduced individual-level behaviors associated with negative affect, and elevated self-reported bonding. Our results indicate that alcohol facilitates bonding during group formation. Assessing nonverbal responses in social contexts offers new directions for evaluating the effects of alcohol.

Validating transdermal alcohol biosensors: a meta-analysis of associations between blood/breath-based measures and transdermal alcohol sensor output.

BACKGROUND AND AIMS: Transdermal alcohol sensors carry immense promise for the continuous assessment of drinking but are inconsistent in detecting more fine-grained indicators of alcohol consumption. Prior studies examining associations between transdermal alcohol concentration (TAC) and blood/breath alcohol concentration (BAC) have yielded highly variable correlations and lag times. The current review aimed to synthesize transdermal validation studies, aggregating results from more than three decades of research to characterize the validity of transdermal sensors for assessing alcohol consumption. METHODS: Databases were searched for studies listed prior to 1 March 2022 that examined associations between transdermal alcohol sensor output and blood and breath-based alcohol measures, resulting in 31 primarily laboratory-derived participant samples (27 precise effect sizes) including both healthy and clinical populations. Correlation coefficients and lag times were pooled using three-level random-effects meta-regression. Independent raters coded study characteristics, including the body position of transdermal sensors (ankle- versus arm/hand/wrist-worn device) and methodological bias (e.g. missing data). RESULTS: Analyses revealed that, in this primarily laboratory-derived sample of studies, the average correlation between TAC and BAC was large in magnitude [r = 0.87, 95% confidence interval (CI) = 0.80, 0.93], and TAC lagged behind BAC by an average of 95.90 minutes (95% CI = 55.50, 136.29). Device body position significantly moderated both TAC-BAC correlation (b = 0.11, P = 0.009) and lag time (b = -69.41, P < 0.001). Lag times for ankle-worn devices were approximately double those for arm/hand/wrist-worn devices, and TAC-BAC correlations also tended to be stronger for arm/hand/wrist-worn sensors. CONCLUSIONS: This meta-analysis indicates that transdermal alcohol sensors perform strongly in assessing blood/breath alcohol concentration under controlled conditions, with particular promise for the newer generation of wrist-worn devices.

The effect of acute alcohol intoxication on alcohol cue salience: An event-related brain potential study.

OBJECTIVE: Alcohol cue salience is considered core to the broader understanding of drinking behaviors. In the present research, we sought to build the knowledge of alcohol cue salience by exploring P3 responses to alcohol images among social drinkers within a large-scale alcohol-administration study. METHOD: Participants (N = 246) were randomly assigned to receive either a moderate dose of alcohol (target BAC = .08%) or a nonalcoholic control beverage. Following beverage administration, participants engaged in image-viewing tasks while EEG was recorded. We examined the impact of alcohol on the amplitude of P3 responses to pictures of alcoholic versus nonalcoholic beverages, exploring both beverage-manipulation and individual-difference moderators of these effects. RESULTS: Results revealed a significant effect of acute alcohol intoxication on P3 responses across stimulus types, with the overall amplitude of P3 being significantly smaller among participants consuming alcohol versus a nonalcoholic beverage. In addition, results revealed a significant main effect of image type, such that P3 amplitude was larger for alcohol images compared to nonalcohol images. No interactions emerged between stimulus type and beverage condition or stimulus type and AUD risk level. CONCLUSIONS: With the aim of better understanding the potential influence of the broader context on responses to individual cues, the present study examined the perceived salience of alcohol cues within a drinking setting. Findings provide evidence for alcohol cue salience that is both robust and also widespread across drinkers. More generally, the present study's findings may offer new directions for understanding neurocognitive processes of alcohol cue salience across contexts. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Mindfulness and acceptance-based interventions with Black Americans: A meta-analysis of intervention efficacy for depressive symptoms.

OBJECTIVE: A growing literature supports mindfulness and acceptance-based interventions (MABIs) for depression prevention and treatment with individuals from dominant cultural groups, and MABIs have been theorized to be well suited to resonate with individuals from nondominant groups. The aim of the current meta-analysis was to determine whether this promise is realized in practice by evaluating the efficacy of MABIs for depression symptoms in Black Americans. METHOD: Thirty studies with an adequate proportion (>20%) of Black Americans were identified using previous reviews and electronic databases, yielding a total of 1,703 participants with an average proportion of 70% Black Americans. Data on moderators (i.e., geographic location, study design, and intervention protocol) and outcomes were extracted and analyzed using metaregression. RESULTS: Results indicated a moderate effect of MABIs on symptom outcomes in the full sample g = 0.48. Effect sizes were similar in study subsets comprising majority (>50%; k = 19) g = 0.39, and predominantly (>90%; k = 10) g = 0.35, Black participants, with no significant moderating effect of racial composition. Effects were moderated by both sample and intervention level characteristics. CONCLUSIONS: The current findings support the conclusion that MABIs are efficacious to varying degrees for Black Americans; with stronger support for use in adult samples than youth samples. These results are promising, and further support efforts to expand research on evidence-based treatments (EBTs) to meet the specific mental health needs of Black Americans. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Mixing Misery and Gin: The Effect of Alcohol Administration on Ostracism Response.

Williams's need-threat model proposes that ostracism responses are reflexive and, because of their evolutionary significance, difficult to diminish. Alcohol is widely consumed in social contexts and for reasons of coping with social stress, and major theories of alcohol propose that intoxication disrupts cognitive appraisal of environmental threats, leading to stress relief. Surprisingly, though, no well-powered experimental research has examined the impact of alcohol intoxication on distress from social ostracism. In three studies across two independent laboratories (N = 438), participants were randomly assigned to receive either an alcoholic or nonalcoholic (i.e., no-alcohol control or placebo) beverage and were exposed to an ostracism (or social inclusion) manipulation. Results, which emerged as remarkably consistent across all studies, indicated strong and consistent effects of ostracism on mood and needs satisfaction among both intoxicated and sober participants. Findings have important implications for ostracism theory and speak to boundary conditions for alcohol's ability to relieve stress.

A new generation of transdermal alcohol biosensing technology: practical applications, machine -learning analytics and questions for future research.

The use of transdermal alcohol monitors has burgeoned in recent years, now encompassing hundreds of thousands of individuals globally. A new generation of sensors promises to expand the range of applications for transdermal technology exponentially, and advances in machine-learning modeling approaches offer new methods for translating the data produced by transdermal devices. This article provides (1) a review of transdermal sensor research conducted to date, including an analysis of methodological features of past studies potentially key in driving reported sensor performance; (2) updates on methodological developments likely to be transformative for the field of transdermal sensing, including the development of new-generation sensors featuring smartphone integration and rapid sampling capabilities as well as developments in machine-learning analytics suited to data produced by these novel sensors and; (3) an analysis of the expanded range of applications for this new generation of sensor, together with corresponding requirements for sensor accuracy and temporal specificity. We also note questions as yet unanswered and key directions for future research.

Alcohol and Neural Dynamics: A Meta-analysis of Acute Alcohol Effects on Event-Related Brain Potentials.

BACKGROUND: An understanding of alcohol's acute neural effects could augment our knowledge of mechanisms underlying alcohol-related cognitive/motor impairment and inform interventions for addiction. Focusing on studies employing event-related brain potential methods, which offer a direct measurement of neural activity in functionally well-characterized brain networks, we present the first meta-analysis to explore acute effects of alcohol on the human brain. METHODS: Databases were searched for randomized laboratory alcohol-administration trials assessing brain activity using event-related potentials. Hedges' g coefficients were pooled using 3-level random-effects meta-regression. RESULTS: Sixty independent randomized controlled trials met inclusion (total N = 2149). Alcohol's effects varied significantly across neural systems, with alcohol leading to reductions in event-related potential components linked with attention (P3b), g = -0.40, 95% CI (-0.50, -0.29), automatic auditory processing (mismatch negativity), g = -0.44, 95% CI (-0.66, -0.22), and performance monitoring (error-related negativity), g = -0.56, 95% CI (-0.79, -0.33). These effects were moderated by alcohol dose, emerging as significant at doses as low as 0.026% blood alcohol concentration and increasing to moderate/large at 0.12%. In contrast, irrespective of dose, relatively small or nonsignificant alcohol effects emerged in other processing domains, including those linked to executive control (N2b responses) and stimulus classification (N2c responses). CONCLUSIONS: Contrary to traditional conceptualizations of alcohol as a "dirty drug" with broad central nervous system depressant effects, results instead support accounts positing targeted alcohol effects in specific processing domains. By identifying alcohol effects on brain systems involved in performance monitoring and attention, results move toward the identification of mechanisms underlying alcohol-related impairment as well as factors reinforcing addiction.

The effect of significant other involvement in treatment for substance use disorders: A meta-analysis.

OBJECTIVE: Substantial research has accrued in support of a key role for social processes in substance use disorders (SUD). Researchers have developed a range of interventions that capitalize on these social processes to bolster treatment outcomes by involving significant others (e.g., romantic partners, family, friends) in SUD treatment. Yet dissemination of these treatments to many contexts has been slow, and information on their broad efficacy is lacking. This meta-analysis aims to quantify the effect of significant other involvement in SUD treatments above and beyond individually-based therapies. METHOD: A total of 4,901 records were screened for randomized controlled trials examining the effect of Significant Other Involved SUD Treatments (SOIT) versus individually-based active comparator treatments. Our search yielded 77 effect sizes based on data from 2,115 individuals enrolled in 16 independent trials. RESULTS: Findings indicated a significant effect of SOIT above and beyond individually-based active comparator treatments for reducing substance use and substance-related problems, d = 0.242, 95% CI [0.148, 0.336], I² = 10.596, Q(15) = 16.778. This effect was consistent across SOIT treatment types and endured 12-18 months after the end of treatment. Analyses of raw mean differences indicated that this effect translates to a 5.7% reduction in substance use frequency-the equivalent of approximately 3 fewer weeks a year of drinking/drug use. CONCLUSION: Findings indicate a significant advantage for SOIT in SUD treatment, and hold interesting conceptual implications for theories of SUD maintenance. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Using machine learning for real-time BAC estimation from a new-generation transdermal biosensor in the laboratory.

BACKGROUND: Transdermal biosensors offer a noninvasive, low-cost technology for the assessment of alcohol consumption with broad potential applications in addiction science. Older-generation transdermal devices feature bulky designs and sparse sampling intervals, limiting potential applications for transdermal technology. Recently a new-generation of transdermal device has become available, featuring smartphone connectivity, compact designs, and rapid sampling. Here we present initial laboratory research examining the validity of a new-generation transdermal sensor prototype. METHODS: Participants were young drinkers administered alcohol (target BAC = .08 %) or no-alcohol in the laboratory. Participants wore transdermal sensors while providing repeated breathalyzer (BrAC) readings. We assessed the association between BrAC (measured BrAC for a specific time point) and eBrAC (BrAC estimated based only on transdermal readings collected in the immediately preceding time interval). Extra-Trees machine learning algorithms, incorporating transdermal time series features as predictors, were used to create eBrAC. RESULTS: Failure rates for the new-generation prototype sensor were high (16 %-34 %). Among participants with useable new-generation sensor data, models demonstrated strong capabilities for separating drinking from non-drinking episodes, and significant (moderate) ability to differentiate BrAC levels within intoxicated participants. Differences between eBrAC and BrAC were 60 % higher for models based on data from old-generation vs new-generation devices. Model comparisons indicated that both time series analysis and machine learning contributed significantly to final model accuracy. CONCLUSIONS: Results provide favorable preliminary evidence for the accuracy of real-time BAC estimates from a new-generation sensor. Future research featuring variable alcohol doses and real-world contexts will be required to further validate these devices.

A multimodal, longitudinal investigation of alcohol's emotional rewards and drinking over time in young adults.

Theories of alcohol use disorder (AUD) have long suggested that alcohol's emotional rewards play a key role in reinforcing problematic drinking. Studies employing survey methods, in which participants recall and aggregate their experiences with alcohol in a single questionnaire, indicate that self-reported expectancies and motivations surrounding alcohol's emotional rewards predict problematic drinking trajectories over time. The current study is the first to combine laboratory alcohol-administration, ambulatory methods, and longitudinal follow-ups to assess whether alcohol's ability to enhance positive mood and reduce negative mood predicts later drinking problems. Sixty young heavy social drinkers (50% female) participated in laboratory-based alcohol-administration, attending both alcohol (target blood alcohol concentration [BAC] .08%) and no-alcohol laboratory sessions. Forty-eight of these participants also wore transdermal alcohol monitors and completed mood surveys outside the laboratory for 7 days. Participants reported on their drinking at 18-month follow-up (90% compliance). Controlling for baseline drinking, greater negative mood reduction from alcohol at baseline predicted more drinking problems at follow-up, an effect that emerged as consistent across methods capturing alcohol's emotional rewards in the laboratory, b = -.24, p = .02, as well as via ambulatory methods, b = -3.14, p = .01. Greater positive mood enhancement from alcohol, captured via laboratory methods, also predicted drinking problems, b = .16, p = .03, and binge drinking, b = 3.22, p = .02, at follow-up. Models examining drinking frequency/quantity were nonsignificant. Results provide support for emotional reward as a potential factor in the development of problematic drinking. (PsycInfo Database Record (c) 2020 APA, all rights reserved).