Acceptability and validity of using the BACtrack skyn wrist-worn transdermal alcohol concentration sensor to capture alcohol use across 28 days under naturalistic conditions - A pilot study

Effects of nicotine-alcohol co-use on alcohol-induced blackouts and other alcohol-related consequences in college students

RATIONALE

Alcohol-induced blackouts (AIBs) are common in college students and are associated with other alcohol-related consequences. Alcohol-nicotine co-use is also common in this population. Nicotine has cognitive-enhancing properties impacting multiple cognitive domains, including those impaired by alcohol (e.g., attention), but it is unclear whether nicotine affects AIB risk or the relationship between AIBs and other alcohol-related consequences.

OBJECTIVES

We examined the moderating effects of nicotine use on the associations between (a) alcohol and AIBs and (b) AIBs and other consequences (total and serious: sexual, legal, or those with potential to cause great harm).

METHODS

College students who reported past semester heavy drinking and at least 1 AIB (N = 79, 55.7% female, 86.1% White) wore alcohol sensors and completed daily diaries over four consecutive weekends (89.9% completion). Multilevel models were conducted to test for moderating effects of nicotine (yes/no) on the alcohol-AIB relationship and the AIB-consequence relationship, adjusting for sex, race/ethnicity, and baseline nicotine use.

RESULTS

Concurrent alcohol and nicotine use did not moderate the alcohol-AIB relationship, but weakened the associations between AIBs and both (1) total consequences and (2) serious consequences. On days with nicotine use, AIBs were associated with approximately 30% fewer total consequences and 50% fewer serious consequences than days without nicotine use.

CONCLUSIONS

College students experienced fewer total and serious consequences on AIB nights when nicotine was used compared to AIB nights when nicotine was not used. Future research should explore potential mechanisms underlying the observed effects.

Stigma and Behavior Change Techniques in Substance Use Recovery: Qualitative Study of Social Media Narratives

BACKGROUND

Existing literature shows that persons with substance use disorder (SUD) experience different stages of readiness to reduce or abstain from substance use, and tailoring intervention change strategies to these stages may facilitate recovery. Moreover, stigma may serve as a barrier to recovery by preventing persons with SUDs from seeking treatment. In recent years, the behavior change technique (BCT) taxonomy has increasingly become useful for identifying potential efficacious intervention components; however, prior literature has not addressed the extent to which these techniques may naturally be used to recover from substance use, and knowledge of this may be useful in the design of future interventions.

OBJECTIVE

We take a three-step approach to identifying strategies to facilitate substance use recovery: (1) characterizing the extent to which stages of change are expressed in social media data, (2) identifying BCTs used by persons at different stages of change, and (3) exploring the role that stigma plays in recovery journeys.

METHODS

We collected discussion posts from Reddit, a popular social networking site, and identified subreddits or discussion forums about 3 substances (alcohol, cannabis, and opioids). We then performed qualitative data analysis using a hybrid inductive-deductive method to identify the stages of change in social media authors' recovery journeys, the techniques that social media content authors used as they sought to quit substance use, and the role that stigma played in social media authors' recovery journeys.

RESULTS

We examined 748 posts pertaining to 3 substances: alcohol (n=316, 42.2%), cannabis (n=335, 44.8%), and opioids (n=135, 18%). Social media content representing the different stages of change was observed, with the majority (472/748, 63.1%) of narratives representing the action stage. In total, 11 categories of BCTs were identified. There were similarities in BCT use across precontemplation, contemplation, and preparation stages, with social support seeking and awareness of natural consequences being the most common. As people sought to quit or reduce their use of substances (action stage), we observed a variety of BCTs, such as the repetition and substitution of healthful behaviors and monitoring and receiving feedback on their own behavior. In the maintenance stage, reports of diverse BCTs continue to be frequent, but offers of social support also become more common than in previous stages. Stigma was present throughout all stages. We present 5 major themes pertaining to the manifestation of stigma.

CONCLUSIONS

Patterns of BCT use and stigmatizing experiences are frequently discussed in social media, which can be leveraged to better understand the natural course of recovery from SUD and how interventions might facilitate recovery from substance use. It may be important to incorporate stigma reduction across all stages of the recovery journey.

Use of Wearable Transdermal Alcohol Sensors for Monitoring Alcohol Consumption After Detoxification With Contingency Management: Pilot Randomized Feasibility Trial

BACKGROUND

Wearable transdermal alcohol sensor (TAS) devices generate continuous data on alcohol consumption through the indiscernible sweat vapors on the skin. This continuous alcohol monitoring capability could provide a new method for alcohol services to monitor service users at various stages of their alcohol treatment.

OBJECTIVE

We aimed to assess the feasibility of using a TAS as part of alcohol treatment with alcohol service users using the device with or without contingency management (CM).

METHODS

A feasibility study was conducted of a convenience sample of 29 current service users from 3 South London alcohol services. Participants were randomized into either a control (treatment as usual) or CM group (treatment as usual+CM). We assessed the feasibility of enrollment, participation, device tampering and return, and device wearability and the accuracy of data capture. These data were reported descriptively where appropriate, the groups were compared, and alcohol self-report data were compared to the transdermal alcohol concentration to assess accuracy.

RESULTS

A total of 34 individuals were approached, and 32 (94%) were enrolled and randomized (n=17, 53% to the control group and n=15, 47% to the CM group) over 5 months. In total, 3 participants withdrew (n=2, 67% from the control group and n=1, 33% from the CM group). There was a total of 203 meetings arranged (29 participants × 7 meetings), and 185 (91.1%) were attended. Only 1 of the 29 participants (3%) admitted to turning the TAS off to avoid monitoring. There were some issues with the TAS not functioning properly and not being able to be cleaned. Removals were recorded, but the definition of TAS removal may need to be improved for future trials. There was a high TAS return rate (28/29, 97% of the participants returned the TAS). Secondary outcomes suggest that the BACtrack Skyn remains an accurate tool to monitor alcohol consumption compared to self-report data and that it is acceptable to wearers over 2 weeks, with many participants (27/28, 96%) answering that they would wear it again and for longer but that the CM procedure could be made clearer.

CONCLUSIONS

The delivery of CM via a TAS was feasible in this study, but recommendations for a future larger trial include that the study design should be changed to provide an operationalized rather than manual method of checking whether TAS data meet CM criteria. This would reduce researcher burden and researcher and participant time. Current recruitment and research meeting design seem suitable for a future larger trial.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number (ISRCTN) ISRCTN46845361; https://www.isrctn.com/ISRCTN46845361.

Serious harm reduction protective behavioral strategies reduce consequences associated with alcohol-induced blackouts in college students

OBJECTIVE

Alcohol-induced blackouts (AIBs) have been associated with increased alcohol-related consequences. Serious harm reduction (SHR) protective behavioral strategies may reduce consequences when students are drinking heavily. We examined whether SHR weakened the relationship between AIBs and a) total consequences and b) serious consequences (e.g., sexual assault) only.

METHODS

Students were eligible if they were aged 18-22  years, in their second or third year of college, reported drinking 4 + drinks on a typical Friday or Saturday, experienced ≥ 1 AIB in the past semester, owned an iPhone, and were willing to wear a sensor for 3  days each weekend. Students (N = 79, 55.7 % female, 86.1 % White, Mage = 20.1) wore sensors and completed daily diaries over four consecutive weekends (852 total surveys; 89.9 % completion rate). Linear multilevel models were conducted to test for moderating effects of SHR.

RESULTS

SHR weakened the association between AIBs and total consequences. At low (-1 SD) SHR, days with an AIB had an additional 1.46 consequences compared to days without an AIB, on average. At high (+1 SD) SHR, days with an AIB had an additional 0.94 consequences compared to days without an AIB, on average. SHR did not change the association between AIBs and serious consequences.

CONCLUSIONS

Students experienced approximately 50% more consequences on nights when they had an AIB and used below average numbers of SHR compared to nights when they had an AIB and used above average numbers of SHR. These findings suggest that student drinking interventions should include SHR to reduce harm associated with drinking and AIBs.

Profiles of alcohol intoxication and their associated risks in young adults' natural settings: A multilevel latent profile analysis applied to daily transdermal alcohol concentration data

OBJECTIVE

Transdermal alcohol concentration (TAC) sensors capture aspects of drinking events that self-reports cannot. The multidimensional nature of TAC data allows novel classification of drinking days and identification of associated behavioral and contextual risks. We used multilevel latent profile analysis (MLPA) to create day-level profiles of TAC features and test their associations with (a) daily behaviors and contexts and (b) risk for alcohol use disorders at baseline.

METHOD

Two hundred twenty-two regularly heavy-drinking young adults (Mage = 22.3) completed the Alcohol Use Disorders Identification Test (AUDIT) at baseline and then responded to mobile phone surveys and wore TAC sensors for six consecutive days. MLPA identified day-level profiles using four TAC features (peak, rise rate, fall rate, and duration). TAC profiles were tested as correlates of daily drinking behaviors, contexts, and baseline AUDIT.

RESULTS

Four profiles emerged: (a) high-fast (8.5% of days), (b) moderate-fast (12.8%), (c) low-slow (20.4%), and (d) little-to-no drinking days (58.2%). Profiles differed in the odds of risky drinking behaviors and contexts. The highest risk occurred on high-fast days, followed by moderate-fast, low-slow, and little-to-no drinking days. Higher baseline AUDIT predicted higher odds of high-fast and moderate-fast days.

CONCLUSIONS

Days with high and fast intoxication are reflective of high-risk drinking behaviors and were most frequent among those at risk for alcohol use disorders. TAC research using MLPA may offer novel and important insights to intervention efforts. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Self-Determined Motivation for Alcohol Use and Drinking Frequency, Intensity, and Consequences

Objective: Drinking motives predict drinking behaviors and outcomes among adults. Drinking motives are rarely studied using self-determination theory (SDT), which aligns with harm-reduction approaches to alcohol use, but SDT can offer a complementary theoretical framework to existing drinking motives frameworks that may help explain the observed heterogeneity in drinking motives and account for more variance in drinking outcomes. This study examined the associations between five SDT-based drinking motives with drinking frequency, intensity, and consequences. Method: A total number of 630 adults (Mage = 21.5, 55% female, 88% undergraduates) rated drinking motives using the Comprehensive Relative Autonomy Index for Drinking (CRAI-Drinking) and the Drinking Motives Questionnaire (DMQ), typical alcohol consumption, and negative and positive drinking consequences. Results: Poisson regressions indicated that intrinsic (IRR = 1.13) and identified (IRR = 1.11) regulations were significantly associated with drinking frequency, identified (IRR = 0.94) and positive introjected (IRR = 1.07) regulations were significantly associated with drinking intensity, and amotivation (IRR = 1.16) and intrinsic regulation (IRR = 1.09) were associated with negative and positive consequences, respectively, after controlling for other CRAI-Drinking and DMQ scores, sex, and drinking intensity. After accounting for DMQ scores and sex, CRAI-Drinking scores accounted for 1.7%-9.9% additional deviance in drinking behaviors and consequences. Conclusions: Adults high in autonomous reasons for drinking reported low-risk, high-enjoyment drinking experiences. In contrast, adults with higher scores for amotivation for drinking reported more negative consequences, even after accounting for drinking intensity, suggesting that high amotivation for drinking may be a novel signal for future alcohol-related risks. These findings support the idea that SDT provides a useful framework for understanding drinking motives, behaviors, and consequences.

Use of Transdermal Alcohol Sensors in Conjunction With Contingency Management to Reduce Alcohol Consumption in People With Alcohol Dependence Attending Alcohol Treatment Services: Protocol for a Pilot Feasibility Randomized Controlled Trial

BACKGROUND

Wearable technology for objective, continuous, and reliable alcohol monitoring has been developed. These are known as transdermal alcohol sensors (TASs). They can be worn on the wrist or ankle with the sensor pressed against the skin and can measure sweat vapors being emitted from the skin, to record transdermal alcohol concentration (TAC). Previous studies have investigated the accuracy and acceptability of the available TAS brands, but there has been little research into their use in people with alcohol use disorders (AUD).

OBJECTIVE

This feasibility randomized controlled trial aims to explore the feasibility, strengths, and limitations of using a TAS to monitor alcohol consumption in individuals in treatment for AUD with or without contingency management (CM) to promote abstinence or low-level alcohol consumption.

METHODS

The target sample size is 30 (15 randomized to each group). Participants will be recruited through poster adverts at alcohol services. Both groups (control and CM) will wear the TAS (BACtrack Skyn) for 2 weeks in the context of their usual treatment, meeting with the researcher every other weekday. In the last meeting, the participants will complete a postwear survey on their experience of wearing the TAS. The CM group will also receive small financial incentives for low or no alcohol consumption, as measured by the TAS. On days where the TAC peak is below a set threshold (<115.660 g/L), CM group participants will be rewarded with a £5 (US $6.38) voucher. There are financial bonuses if this target is achieved on consecutive days. The researcher will monitor TAC for each day of the study at each research visit and allocate financial incentives to participants according to a set reinforcement schedule.

RESULTS

The first participant was enrolled in June 2023, and the last in December 2023. Data analysis is underway and is estimated to be completed by June 2024. A total of 32 participants were enrolled.

CONCLUSIONS

Most TAS brands have had limited application in clinical settings, and most studies have included healthy adults rather than people with AUD. TAS has the potential to enhance treatment outcomes in clinical alcohol treatment. The accuracy, acceptability, and feasibility of TAS for people with AUD in clinical settings need to be investigated. This is the first study to use TAS in specialized alcohol services with diagnosed AUD individuals currently receiving treatment from a south London alcohol service.

TRIAL REGISTRATION

ISRCTN Registry ISRCTN46845361; https://www.isrctn.com/ISRCTN46845361.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/57653.

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).

Transdermal alcohol concentration features predict alcohol-induced blackouts in college students

BACKGROUND

Alcohol-induced blackouts (AIBs) are common in college students. Individuals with AIBs also experience acute and chronic alcohol-related consequences. Research suggests that how students drink is an important predictor of AIBs. We used transdermal alcohol concentration (TAC) sensors to measure biomarkers of increasing alcohol intoxication (rise rate, peak, and rise duration) in a sample of college students. We hypothesized that the TAC biomarkers would be positively associated with AIBs.

METHODS

Students were eligible to participate if they were aged 18-22 years, in their second or third year of college, reported drinking 4+ drinks on a typical Friday or Saturday, experienced ≥1 AIB in the past semester, owned an iPhone, and were willing to wear a sensor for 3 days each weekend. Students (N = 79, 55.7% female, 86.1% White, Mage = 20.1) wore TAC sensors and completed daily diaries over four consecutive weekends (89.9% completion rate). AIBs were assessed using the Alcohol-Induced Blackout Measure-2. Logistic multilevel models were conducted to test for main effects.

RESULTS

Days with faster TAC rise rates (OR = 2.69, 95% CI: 1.56, 5.90), higher peak TACs (OR = 2.93, 95% CI: 1.64, 7.11), and longer rise TAC durations (OR = 4.16, 95% CI: 2.08, 10.62) were associated with greater odds of experiencing an AIB.

CONCLUSIONS

In a sample of "risky" drinking college students, three TAC drinking features identified as being related to rising intoxication independently predicted the risk for daily AIBs. Our findings suggest that considering how an individual drinks (assessed using TAC biomarkers), rather than quantity alone, is important for assessing risk and has implications for efforts to reduce risk. Not only is speed of intoxication important for predicting AIBs, but the height of the peak intoxication and the time spent reaching the peak are important predictors, each with different implications for prevention.

Signal processing and machine learning with transdermal alcohol concentration to predict natural environment alcohol consumption

Wrist-worn alcohol biosensors continuously and discreetly record transdermal alcohol concentration (TAC) and may allow alcohol researchers to monitor alcohol consumption in participants' natural environments. However, the field lacks established methods for signal processing and detecting alcohol events using these devices. We developed software that streamlines analysis of raw data (TAC, temperature, and motion) from a wrist-worn alcohol biosensor (BACtrack Skyn) through a signal processing and machine learning pipeline: biologically implausible skin surface temperature readings (< 28°C) were screened for potential device removal and TAC artifacts were corrected, features that describe TAC (e.g., rise duration) were calculated and used to train models (random forest and logistic regression) that predict self-reported alcohol consumption, and model performances were measured and summarized in autogenerated reports. The software was tested using 60 Skyn data sets recorded during 30 alcohol drinking episodes and 30 nonalcohol drinking episodes. Participants (N = 36; 13 with alcohol use disorder) wore the Skyn during one alcohol drinking episode and one nonalcohol drinking episode in their natural environment. In terms of distinguishing alcohol from nonalcohol drinking, correcting artifacts in the data resulted in 10% improvement in model accuracy relative to using raw data. Random forest and logistic regression models were both accurate, correctly predicting 97% (58/60; AUC-ROCs = 0.98, 0.96) of episodes. Area under TAC curve, rise duration of TAC curve, and peak TAC were the most important features for predictive accuracy. With promising model performance, this protocol will enhance the efficiency and reliability of TAC sensors for future alcohol monitoring research. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Abstinence-contingent wage supplements for adults experiencing homelessness and alcohol use disorder: A randomized clinical trial

This study evaluated the effectiveness of abstinence-contingent wage supplements in promoting alcohol abstinence and employment in adults experiencing homelessness and alcohol use disorder. A randomized clinical trial was conducted from 2019 to 2022. After a 1-month Induction period, 119 participants were randomly assigned to a Usual Care Control group (n = 57) or an Abstinence-Contingent Wage Supplement group (n = 62). Usual Care participants were offered counseling and referrals to employment and treatment programs. Abstinence-Contingent Wage Supplement participants could earn stipends for working with an employment specialist and wage supplements for working in a community job but had to maintain abstinence from alcohol as determined by transdermal alcohol concentration monitoring devices to maximize pay. Abstinence-Contingent Wage Supplement participants reported significantly higher rates of alcohol abstinence than Usual Care participants during the 6-month intervention (82.8% vs. 60.2% of months, OR = 3.4, 95% CI 1.8 to 6.3, p < .001). Abstinence-Contingent Wage Supplement participants were also significantly more likely to obtain employment (51.3% vs. 31.6% of months, OR = 2.6, 95% CI 1.5 to 4.4, p < .001) and live out of poverty (38.2% vs. 16.7% of months, OR = 3.7, 95% CI 2.0 to 7.1, p < .001) than Usual Care participants. These findings suggest that Abstinence-Contingent Wage Supplements can promote alcohol abstinence and employment in adults experiencing homelessness and alcohol use disorder. ClinicalTrials.gov Identifier: NCT03519009.

Use of the BACtrack Skyn alcohol biosensor: Practical applications for data collection and analysis

AIMS

Alcohol biosensors, including the BACtrack Skyn, provide an objective and passive method of continuously assessing alcohol consumption in the natural environment. Despite the many strengths of the Skyn, six key challenges in the collection and processing of data include (1) identifying consumed alcohol; (2) identifying environmental alcohol; (3) identifying and determining the source of missing or invalid data; (4) achieving high participant adherence; (5) integrating Skyn and self-report data; and (6) implications for statistical inference. In this report we outline these challenges, provide recommendations to address them and identify future needs.

DESIGN AND SETTINGS

Procedures from several laboratory and field-based pilot studies are presented to demonstrate practical recommendations for Skyn use. Data from a pilot study including a 7-day ecological momentary assessment period are also presented to evaluate effects of environmental alcohol on BACtrack Skyn readings.

CONCLUSIONS

To address challenges in the collection and processing of data from the BACtrack Skyn alcohol biosensor, researchers should identify goals in advance of data collection to anticipate the processing necessary to interpret Skyn data. The Transdermal Alcohol Sensor Data Macro (TASMAC) version 2.0 software can help to process data rapidly; identify drinking events, missing data and environmental alcohol; and integrate the sensor with self-report data. Thorough participant orientation and regular contact in field studies can reduce missing data and enhance adherence. Many recommended methods for Skyn use are applicable to other alcohol sensors and wearable devices.