Cue-elicited heart rate variability and attentional bias predict alcohol relapse following treatment

Craving on the move: targeting smoking memories with a novel 3MDR-smoking cessation protocol

Introduction

Improved effectiveness and treatment adherence is needed in smoking cessation (SC) therapies. Another important challenge is to disrupt maladaptive drug-related memories. To achieve these goals, we developed a novel treatment strategy on the basis of motion-assisted memory desensitization and reprocessing (3MDR).

Methods

In this study, the added effect of a distractor task following memory recall during a newly designed 3-day SC version of 3MDR (3MDR-SC) protocol on reducing smoking cue-elicited craving was investigated in abstinent chronic smokers. Chronic smokers were randomly allocated to an active 3MDR-SC group (receiving 3MDR-SC with a working memory distractor task) (n = 42) or a control 3MDR-SC group (receiving 3MDR-SC with a non-distracting task) (n = 39). Smoking cue-induced craving and physiological measures were assessed at baseline (T0) and 1 day after the intervention (T4), and smoking behavior was measured at T0 and 2-week (FU1) and 3-month (FU2) follow-up.

Results

Significant decreases in cue-induced craving from T0 to T4 and daily cigarette use from T0 to FU1 and FU2 were observed but not differ between the two experimental groups. Cue-induced changes in heart-rate variability and skin conductance, which did not differ from T0 to T4, and relapse at FU2 were also not different between groups. Dropout rate during intervention was 2.5%.

Conclusions

The 3-day 3MDR-SC intervention resulted in a reduction in cue-induced craving and smoking behavior and showed very good treatment adherence. There was no added effect of the distractor task on 3MDR-SC efficacy. Further studies, including a treatment as usual control, are needed to confirm 3MDR-SC as an effective SC therapy.

Pavlovian cue-evoked alcohol seeking is disrupted by ventral pallidal inhibition

Cues paired with alcohol can be potent drivers of craving, alcohol-seeking, consumption, and relapse. While the ventral pallidum is implicated in appetitive and consummatory responses across several reward classes and types of behaviors, its role in behavioral responses to Pavlovian alcohol cues has not previously been established. Here, we tested the impact of optogenetic inhibition of ventral pallidum on Pavlovian-conditioned alcohol-seeking in male Long Evans rats. Rats underwent Pavlovian conditioning with an auditory cue predicting alcohol delivery to a reward port and a control cue predicting no alcohol delivery, until they consistently entered the reward port more during the alcohol cue than the control cue. We then tested the within-session effects of optogenetic inhibition during 50% of cue presentations. We found that optogenetic inhibition of ventral pallidum during the alcohol cue reduced port entry likelihood and time spent in the port, and increased port entry latency. Overall, these results suggest that normal ventral pallidum activity is necessary for Pavlovian alcohol-seeking.

CT-optimal touch modulates alcohol-cue-elicited heart rate variability in Alcohol Use Disorder patients during early abstinence: a randomized controlled study

Alcohol Use Disorder (AUD) is a chronic brain disorder associated with a high risk of relapse and a limited treatment efficacy. Relapses may occur even after long periods of abstinence and are often triggered by stress or cue induced alcohol craving. C-tactile afferents (CT) are cutaneous nerve fibers postulated to encode pleasant affective touch and known to modulate physiological stress responses. However, their translational potential has not yet been explored extensively in controlled clinical trials. This randomized controlled study aimed to investigate the potential of CT stimulation in modulating relapse predicting biomarkers, physiological cue-reactivity, and subjective alcohol craving in AUD patients in early abstinence. Twenty-one participants meeting DSM-5 criteria for mild to moderate AUD received CT-optimal touch or a non-CT-optimal control treatment while exposed to neutral, stress-inducing, and alcohol-related visual stimuli. The tactile treatment was provided with a robotic device, eliminating the social elements of touch. Heart rate variability (HRV), salivary cortisol, and subjective craving were assessed at the baseline, during and after the treatment and stimuli exposure. The results showed that CT-optimal touch significantly reduced alcohol-cue-elicited standard deviation of normal-to-normal intervals (SDNN) HRV compared to the control group, shifting the HRV reactivity to the direction known to indicate lower relapse susceptibility. Cortisol levels showed no significant differences between the groups, and subjective alcohol craving increased after alcohol cue exposure in both groups. This study found that CT-optimal touch modulates autonomic cue-reactivity in AUD patients, encouraging further research on the therapeutic potential of affective touch. Future research should explore the long-term effects and real-world clinical relevance of CT-optimal touch in alcohol relapse prevention.

Heart rate variability: A primer for alcohol researchers

Problem alcohol drinking remains a major cost and burden for society. Also, rates of problem drinking in women have dramatically increased in recent decades, and women are at risk for more alcohol problems and comorbidities. The purpose of this commentary is to discuss the potential utility of cardiac measures, including heart rate (HR) and HR variability (HRV), as markers of individual and sex differences in the drive to drink alcohol. We recently used cardiac telemetry in female and male adult rats to determine whether different cardiac markers, including HR and HRV, would differently predict alcohol and anxiety-like behavior across the sexes. Indeed, female behaviors related to HRV measures that indicate more parasympathetic (PNS) influence (the "rest and digest" system). In contrast, male behaviors are associated more with sympathetic (SNS) indicators (the activation system). Remarkably, similar sex differences in PNS versus SNS engagement under challenge are seen in several human studies, suggesting strong cross-species convergence in differential autonomic regulation in females and males. Here, we describe the larger challenges that alcohol addiction presents, and how HRV measures may provide new biomarkers to help enhance development of more individualized and sex-specific treatments. We briefly explain the physiological systems underlying cardiac PNS and SNS states, and how specific HRV metrics are defined and validated, especially why particular HRV measures are considered to reflect more PNS versus SNS influence. Finally, we describe hormonal influences and sex differences in brain circuits related to cardiac autonomic regulation. Together, these findings show that HR and HRV have potential for uncovering key underlying mechanisms of sex and individual differences in autonomic drivers, which could guide more personalized treatment.

Pavlovian cue-evoked alcohol seeking is disrupted by ventral pallidal inhibition

Cues paired with alcohol can be potent drivers of craving, alcohol-seeking, consumption, and relapse. While the ventral pallidum is implicated in appetitive and consummatory responses across several reward classes and types of behaviors, its role in behavioral responses to Pavlovian alcohol cues has not previously been established. Here, we tested the impact of optogenetic inhibition of ventral pallidum on Pavlovian-conditioned alcohol-seeking in male Long Evans rats. Rats underwent Pavlovian conditioning with an auditory cue predicting alcohol delivery to a reward port and a control cue predicting no alcohol delivery, until they consistently entered the reward port more during the alcohol cue than the control cue. We then tested the within-session effects of optogenetic inhibition during 50% of cue presentations. We found that optogenetic inhibition of ventral pallidum during the alcohol cue reduced port entry likelihood and time spent in the port, and increased port entry latency. Overall, these results suggest that normal ventral pallidum activity is necessary for Pavlovian alcohol-seeking.

An explorative single-arm clinical study to assess craving in patients with alcohol use disorder using Virtual Reality exposure (CRAVE)-study protocol

BACKGROUND

Alcohol use disorder (AUD) belongs to the most burdensome clinical disorders worldwide. Current treatment approaches yield unsatisfactory long-term effects with relapse rates up to 85%. Craving for alcohol is a major predictor for relapse and can be intentionally induced via cue exposure in real life as well as in Virtual Reality (VR). The induction and habituation of craving via conditioned cues as well as extinction learning is used in Cue Exposure Therapy (CET), a long-known but rarely used strategy in Cognitive Behavioral Therapy (CBT) of AUD. VR scenarios with alcohol related cues offer several advantages over real life scenarios and are within the focus of current efforts to develop new treatment options. As a first step, we aim to analyze if the VR scenarios elicit a transient change in craving levels and if this is measurable via subjective and psychophysiological parameters.

METHODS

A single-arm clinical study will be conducted including n = 60 patients with AUD. Data on severity of AUD and craving, comorbidities, demographics, side effects and the feeling of presence in VR will be assessed. Patients will use a head-mounted display (HMD) to immerse themselves into three different scenarios (neutral vs. two target situations: a living room and a bar) while heart rate, heart rate variability, pupillometry and electrodermal activity will be measured continuously. Subjective craving levels will be assessed before, during and after the VR session.

DISCUSSION

Results of this study will yield insight into the induction of alcohol craving in VR cue exposure paradigms and its measurement via subjective and psychophysiological parameters. This might be an important step in the development of innovative therapeutic approaches in the treatment of patients with AUD.

TRIAL REGISTRATION

This study was approved by the Charité-Universitätsmedizin Berlin Institutional Review Board (EA1/190/22, 23.05.2023). It was registered on ClinicalTrials.gov (NCT05861843).

Severity identification for internet gaming disorder using heart rate variability reactivity for gaming cues: a deep learning approach

Background

The diminished executive control along with cue-reactivity has been suggested to play an important role in addiction. Hear rate variability (HRV), which is related to the autonomic nervous system, is a useful biomarker that can reflect cognitive-emotional responses to stimuli. In this study, Internet gaming disorder (IGD) subjects' autonomic response to gaming-related cues was evaluated by measuring HRV changes in exposure to gaming situation. We investigated whether this HRV reactivity can significantly classify the categorical classification according to the severity of IGD.

Methods

The present study included 70 subjects and classified them into 4 classes (normal, mild, moderate and severe) according to their IGD severity. We measured HRV for 5 min after the start of their preferred Internet game to reflect the autonomic response upon exposure to gaming. The neural parameters of deep learning model were trained using time-frequency parameters of HRV. Using the Class Activation Mapping (CAM) algorithm, we analyzed whether the deep learning model could predict the severity classification of IGD and which areas of the time-frequency series were mainly involved.

Results

The trained deep learning model showed an accuracy of 95.10% and F-1 scores of 0.995 (normal), 0.994 (mild), 0.995 (moderate), and 0.999 (severe) for the four classes of IGD severity classification. As a result of checking the input of the deep learning model using the CAM algorithm, the high frequency (HF)-HRV was related to the severity classification of IGD. In the case of severe IGD, low frequency (LF)-HRV as well as HF-HRV were identified as regions of interest in the deep learning model.

Conclusion

In a deep learning model using the time-frequency HRV data, a significant predictor of IGD severity classification was parasympathetic tone reactivity when exposed to gaming situations. The reactivity of the sympathetic tone for the gaming situation could predict only the severe group of IGD. This study suggests that the autonomic response to the game-related cues can reflect the addiction status to the game.

The Moderating Role of Sex in the Relation between Cue-Induced Craving and Resting-State Functional Connectivity in the Salience Network of Non-Clinically Diagnosed Drinkers

INTRODUCTION

Previous research indicates a relation between craving and increased connectivity in the resting-state salience network. However, the link between cue-induced craving and connectivity in the salience network remains unclear. Further investigation is needed to understand the effect of sex on the relationship between cue-induced craving and the salience network. We investigated the role of sex in the association between the resting-state functional connectivity (RSFC) salience network and subjective cue-induced craving.

METHODS

Twenty-six males (mean age = 25.3) and 23 females (mean age = 26.0), with a score of 12 or higher on the alcohol use disorder identification test, were included in the current study. No significant difference in age was observed between males and females. Participants underwent a resting-state MRI scan for 6 min. Following the MRI scan, participants completed an alcohol cue-exposure task for 5.5 min to assess cue-induced craving using the desire to drink alcohol questionnaire. We applied independent component analysis methods to determine functional connectivity within the salience network. Subsequently, we investigated how cue-induced craving is related to the salience network's RSFC and if this relationship is moderated by sex.

RESULTS

The association between the salience network and cue-induced craving was not statistically significant nor did we find a moderating effect for sex.

CONCLUSION

The null findings in the study may be explained by a lack of power. Alternatively, alcohol use sex disparities may be more prevalent in the recreational/impulsive stage, whereas participants in our study were in the later stage of addiction.

Trial-level bias score versus mean bias score: Comparison of the reliability and external validity using dot-probe task among daily smokers

INTRODUCTION

Attentional bias (AB) is an individual difference risk factor that represents the extent to which cigarette cues capture one's attention. AB is typically indexed by mean bias score (MBS), theoretically assuming that AB is static. However, poor reliability of MBS has threatened valid interpretation of the results on AB. Based on observed trial-by-trial temporal fluctuation and variability of attentional allocation, trial-level bias score (TLBS) has been introduced as an alternative index with evidence of better psychometric properties in various populations, as compared to MBS. However, such evidence is limited among daily smokers. The current study aimed to replicate and extend extant findings in a sample of daily smokers by hypothesizing that TLBS, as compared to MBS, would demonstrate superior reliability and external validity.

METHODS

Forty-eight daily smokers completed self-reports, ad-libitum smoking, and a dot-probe task three times, which was comprised of 36 pairs of pictorial stimuli of cigarette and neutral cues, yielding 144 total trials.

RESULTS

The TLBS demonstrated superior internal (range intra class correlation [ICC] = 0.79-0.95) and test-retest reliability (range ICC = 0.64-0.88) compared to MBS (range ICC = 0.31-0.40 and 0.06-0.16, respectively). However, few significant relations between either the MBS or TLBS and measures of biobehavioral and self-report indices of smoking reinforcement were observed.

CONCLUSIONS

The current findings demonstrate that TLBS, as compared to MBS, is a more reliable measure of AB among daily smokers, while evidence of its external validity is limited.

Mindfulness-based interventions in inpatient treatment for Substance Use Disorders: A systematic review

Inpatient treatment for Substance Use Disorder (SUD), such as Therapeutic Communities and Residential Treatment has been used to test the effect of Mindfulness-Based Interventions (MBI) over different outcomes. Although there is evidence of the effectiveness of MBIs, little is known about the particularities that the place may have in the outcomes. The main objective of this Systematic Review was to evaluate the effectiveness of MBIs for SUDs performed in the inpatient context. PubMed, Web of Science and PsycInfo were used for the search. Quantitative and qualitative studies with no control, usual treatment or other active comparator intervention for SUDs inpatient treatment from 1980 to 2020 were included. From 21 selected studies, 18 were quantitative and 3 qualitative; 12 studies were RCT. Most samples were comprised with women. Based on characteristics of outcomes, we were able to divide them into: Substance Use and Associated Outcomes, Stress, Impulsivity e Evaluation of the MBI protocol. Results suggest that stress assessment is a determining factor for treatment success in these settings. Regarding substance use, although several outcomes have been assessed, the most remarkable results were craving reduction and improvement in treatment adherence. There is evidence that MBIs in inpatient settings benefited those who participated in the experimental groups on some outcomes, such as stress and substance use. Little is mentioned about the impact of the environment over the outcomes and short follow-ups were a relevant limitation of most of the studies. Future assessments must increase follow-up time and evaluate the relationship between the context and the MBI.

Pilot examination of stress, heart rate variability, and alcohol craving and use among female veterans

Rates of alcohol use disorder (AUD) are increasing among civilian and veteran populations of women in the United States, and stress pathophysiology (i.e., abnormal acute and long-term change in physiological responses to stress) is central to the maintenance of alcohol misuse within this population. Heart rate variability (HRV) is one measure of stress regulation that may help to explain the association of stress with alcohol misuse among women. In the current analysis of pilot data, 20 women veterans attended an in-person laboratory session and completed 35 daily assessments of their alcohol use and craving. During the lab session, the effects of a stress induction procedure on self-reported alcohol craving and HRV were assessed. HRV was continuously measured and indexed in the time domain, using the root mean square of successive differences between normal heartbeats (RMSSD). Alcohol craving and use during the longitudinal 35-day study period were measured via self-report questionnaires sent to participants' phones. Results indicated that resting HRV in the lab was positively associated with odds of daily craving. Moreover, HRV during the stressor, as measured in lab, was positively associated with (1) overall alcohol craving in the lab (i.e., with resting and post-stress craving), and (2) number of daily drinks during the 35-day study period. This pilot study suggests the potential role of HRV in response to stressors in predicting alcohol craving and use among female veterans. It provides pilot data for research on stress-reactive HRV as a biomarker for alcohol misuse among women, and discusses directions for future research.

Emotional distress and pain catastrophizing predict cue-elicited opioid craving among chronic pain patients on long-term opioid therapy

BACKGROUND

Individuals who use illicit substances exhibit cue-elicited craving and autonomic cue-reactivity when exposed to cues associated with past drug use. However, little is known about this phenomenon among chronic pain patients on long-term opioid therapy (LTOT). Negative cognitive-emotional reactivity in general (e.g., distress) and cognitive-emotional reactivity specific to pain (e.g., pain catastrophizing) might drive cue-reactivity independent of pain severity. Here we examined emotional distress and pain catastrophizing as predictors of cue-reactivity among a sample of chronic pain patients receiving LTOT. We also tested whether associations between distress, catastrophizing, and cue-reactivity differed as a function of opioid misuse status.

MATERIALS AND METHODS

Patients receiving LTOT (N = 243) were classified as exhibiting aberrant behavior consistent with opioid misuse (MISUSE+, n = 145) or as using opioids as prescribed (MISUSE-, n = 97). Participants completed assessments of pain catastrophizing and emotional distress and then participated in an opioid cue-reactivity task one week later. Cue-elicited opioid craving and autonomic cue-reactivity were measured with craving ratings and high-frequency heart rate variability (HRV), respectively.

RESULTS

Distress and catastrophizing predicted cue-elicited craving and HRV, whereas pain severity did not. Misuser status moderated the relationship between emotional distress and self-reported craving, such that higher levels of distress predicted craving among the MISUSE+ group, but not among the MISUSE- group. No moderating effects were found for catastrophizing.

CONCLUSIONS

Findings suggest that although opioids are prescribed for analgesia, the exacerbating influence of negative cognitive-emotional reactivity, both in general and specific to pain, on cue-elicited opioid craving extends beyond the effects of pain severity alone.

Attentional Bias to Alcohol Information: a Novel Dual-Probe Task

BACKGROUND

Even when motivated to consume less alcohol, attempts to do so are not always successful. Attentional bias to positive and negative alcohol-related information may play a role in shaping unintended drinking behaviour. The present exploratory study adapted a novel attentional bias task, to test whether selective attention to positive relative to negative information about alcohol consumption predicts mismatch between alcohol consumption intention and alcohol consumption behaviour.

METHOD

Thirty-five university students attempting to reduce their alcohol consumption participated in the study. Participants completed a novel attentional bias assessment task where two positive and negative audio-visual messages about alcohol consumption were simultaneously presented. At random intervals during these messages, two different probes were briefly and simultaneously presented, so that only one could be detected. Attention to positive vs. negative messages was inferred from the location of the probe recorded by the participant. Alcohol consumption in relation to participants' goals was measured using a real-time diary over the subsequent 7 days.

RESULTS

An attentional bias towards positive (relative to negative) messages about alcohol consumption predicted the degree to which participants consumed more alcohol than planned, but did not predict alcohol consumption itself.

CONCLUSION

This is the first study to our knowledge that has investigated the relationship between biased attention to alcohol-related information and variation in the success of intended reduction in alcohol consumption, and we suggest that it paves the way for further research into the role of attentional biases in health risk behaviours.

Changes in Drug-Related Implicit Associations during Substance Use Disorder Treatment: The Role of the Therapeutic Context

BACKGROUND

Implicit cognition has been linked to relapse in substance use disorder (SUD). Studies on attentional bias have found different outcomes related to the therapeutic context, finding an association with relapse in inpatients but not in outpatients. There are no similar studies that use associations in semantic memory as a measure of implicit cognition.

OBJECTIVES

(i) to analyze the relationship between a measure of associations in semantic memory and relapse in inpatients and outpatients; (ii) to compare the evolution of these associations between inpatients and outpatients after 3 months of treatment.

METHODS

Eighty nine outpatients and 94 inpatients with SUD for cocaine and alcohol participated in this study. We employed a longitudinal design with a baseline evaluation and follow-up after three months, using the Word Association Task for Drug Use Disorder (WAT-DUD).

RESULTS

The choice of drug-related words predicted relapse in cocaine (odds ratio = 1.97, z = 2.01, p = .045) and alcohol-cocaine (odds ratio = 2.39, z = 2.55, p = .011) use. Follow-up at 3 months revealed a reduction in the choice of drug-related words in inpatients (Z = 2.031, p = .042).

CONCLUSIONS

A greater choice of drug-associated words in the presence of ambiguous images was related to relapse in inpatients but not in outpatients. The inpatients group showed a reduction in the semantic association with drugs during the first three months of treatment.

Raising the bar: improving methodological rigour in cognitive alcohol research

BACKGROUND AND AIMS

A range of experimental paradigms claim to measure the cognitive processes underpinning alcohol use, suggesting that heightened attentional bias, greater approach tendencies and reduced cue-specific inhibitory control are important drivers of consumption. This paper identifies methodological shortcomings within this broad domain of research and exemplifies them in studies focused specifically on alcohol-related attentional bias.

ARGUMENT AND ANALYSIS

We highlight five main methodological issues: (i) the use of inappropriately matched control stimuli; (ii) opacity of stimulus selection and validation procedures; (iii) a credence in noisy measures; (iv) a reliance on unreliable tasks; and (v) variability in design and analysis. This is evidenced through a review of alcohol-related attentional bias (64 empirical articles, 68 tasks), which reveals the following: only 53% of tasks use appropriately matched control stimuli; as few as 38% report their stimulus selection and 19% their validation procedures; less than 28% used indices capable of disambiguating attentional processes; 22% assess reliability; and under 2% of studies were pre-registered.

CONCLUSIONS

Well-matched and validated experimental stimuli, the development of reliable cognitive tasks and explicit assessment of their psychometric properties, and careful consideration of behavioural indices and their analysis will improve the methodological rigour of cognitive alcohol research. Open science principles can facilitate replication and reproducibility in alcohol research.

An Integrated Mechanistic Model of Mindfulness-Oriented Recovery Enhancement for Opioid-Exposed Mother-Infant Dyads

A growing body of neurobiological and psychological research sheds light on the mechanisms underlying the development and maintenance of opioid use disorder and its relation to parenting behavior. Perinatal opioid use is associated with risks for women and children, including increased risk of child maltreatment. Drawing from extant data, here we provide an integrated mechanistic model of perinatal opioid use, parenting behavior, infant attachment, and child well-being to inform the development and adaptation of behavioral interventions for opioid-exposed mother-infant dyads. The model posits that recurrent perinatal opioid use may lead to increased stress sensitivity and reward dysregulation for some mothers, resulting in decreased perceived salience of infant cues, disengaged parenting behavior, disrupted infant attachment, and decreased child well-being. We conclude with a discussion of Mindfulness-Oriented Recovery Enhancement as a means of addressing mechanisms undergirding perinatal opioid use, parenting, and attachment, presenting evidence on the efficacy and therapeutic mechanisms of mindfulness. As perinatal opioid use increases in the United States, empirically informed models can be used to guide treatment development research and address this growing concern.

Initial orientation vs maintenance of attention: Relationship with the severity of dependence and therapeutic outcome in a sample of cocaine use disorder patients

The visual probe paradigm allows for evaluating attentional bias (AB), distinguishing between approach vs avoidance patterns of attention and assessing two different processes when the exposure time to images is manipulated: initial orienting and maintenance of attention. The present study aimed to analyze the predictive capacity of these two processes for substance use disorder severity and therapeutic outcomes of patients with cocaine use disorder in treatment. The sample consisted of 70 outpatients who were starting treatment at a public service. AB was evaluated using a task based on the visual probe (VP) paradigm with images presented under two conditions: 200 ms vs 1000 ms. Cocaine and alcohol use disorder severity, craving, retention in treatment and relapse in consumption were recorded. Cocaine AB in the 1000 ms condition was negatively correlated with the cocaine use disorder severity (r = -0.26), whilst a positive correlation was found between cocaine craving and cocaine AB (r = 0.29). Alcohol use disorder severity negatively correlated with cocaine AB in the 200 ms condition (r = -0.24). Logistic regression analysis revealed that, after controlling for gender, age, and substance use disorder severity, cocaine AB in the 200 ms condition predicted dropout and relapse. Our results suggest that patients who adhere to treatment and remain abstinent tend to show avoidance in the 200 ms condition, with effect sizes of r = 0.29 and 0.30 respectively. The results suggest that training in avoidance strategies could be a valuable way of maintaining adherence and abstinence, as well as improving control of craving.

Use of Mobile Technology Paired with Heart Rate Monitor to Remotely Quantify Behavioral Health Markers among Military Reservists and First Responders

INTRODUCTION

Heart rate variability (HRV) is a biological marker that reflects an individual's autonomic nervous system regulation. Psychological resilience is an individual's ability to recover from an adverse event and return to physiological homeostasis and mental well-being, indicated by higher resting HRV. The Biofeedback Assisted Resilience Training (BART) study evaluates a resilience-building intervention, with or without HRV biofeedback. This article evaluates the feasibility of remote psychophysiological research by validating the HRV data collected.

MATERIALS AND METHODS

The BART platform consists of a mobile health application (BART app) paired to a wearable heart rate monitor. The BART app is installed on the participant's personal phone/tablet to track and collect self-report psychological and physiological data. The platform collects raw heart rate data and processes HRV to server as online biofeedback. The raw data is processed offline to derive HRV for statistical analysis. The following HRV parameters are validated: inter-beat interval, respiratory sinus arrhythmia, low-frequency HRV, biofeedback HRV, and heart period. Bland-Altman and scatter plots are used to compare and contrast online and offline HRV measures. Repeated-measures ANOVA are used to compared means across tasks during the stress (rest, stress, and recovery) and training (rest and paced breathing) sessions in order to validate autonomic nervous system changes to physiological challenges.

RESULTS

The analyses included 245 participants. Bland-Altman plots showed excellent agreement and minimal bias between online and offline unedited inter-beat interval data during the stress session. RMANOVA during the training session indicated a significant strong effect on biofeedback HRV, F(11,390) = 967.96, P < .01. During the stress session, RMANOVA showed significant strong effect on respiratory sinus arrhythmia and low-frequency HRV, and a significant but weak effect on heart period.

CONCLUSIONS

The BART digital health platform supports remote behavioral and physiological data collection, intervention delivery, and online HRV biofeedback.

Instrumental and Pavlovian Mechanisms in Alcohol Use Disorder

Purpose of Review

Current theories of alcohol use disorders (AUD) highlight the importance of Pavlovian and instrumental learning processes mainly based on preclinical animal studies. Here, we summarize available evidence for alterations of those processes in human participants with AUD with a focus on habitual versus goal-directed instrumental learning, Pavlovian conditioning, and Pavlovian-to-instrumental transfer (PIT) paradigms.

Recent Findings

The balance between habitual and goal-directed control in AUD participants has been studied using outcome devaluation or sequential decision-making procedures, which have found some evidence of reduced goal-directed/model-based control, but little evidence for stronger habitual responding. The employed Pavlovian learning and PIT paradigms have shown considerable differences regarding experimental procedures, e.g., alcohol-related or conventional reinforcers or stimuli.

Summary

While studies of basic learning processes in human participants with AUD support a role of Pavlovian and instrumental learning mechanisms in the development and maintenance of drug addiction, current studies are characterized by large variability regarding methodology, sample characteristics, and results, and translation from animal paradigms to human research remains challenging. Longitudinal approaches with reliable and ecologically valid paradigms of Pavlovian and instrumental processes, including alcohol-related cues and outcomes, are warranted and should be combined with state-of-the-art imaging techniques, computational approaches, and ecological momentary assessment methods.

Understanding Attentional Biases in Severe Alcohol Use Disorder: A Combined Behavioral and Eye-Tracking Perspective

RATIONALE

Severe alcohol use disorder (SAUD) is a psychiatric condition linked to cerebral and cognitive consequences. SAUD is notably characterized by an overactivation of the reflexive/reward system when confronted with alcohol-related cues. Such overreactivity generates a preferential allocation of attentional resources toward these cues, labeled as attentional biases (AB). Theoretical assumptions have been made regarding the characteristics of AB and their underlying processes. While often considered as granted, these assumptions remain to be experimentally validated.

AIMS

We first identify the theoretical assumptions made by previous studies exploring the nature and role of AB. We then discuss the current evidence available to establish their validity. We finally propose research avenues to experimentally test them.

METHODS

Capitalizing on a narrative review of studies exploring AB in SAUD, the current limits of the behavioral measures used for their evaluation are highlighted as well as the benefits derived from the use of eye-tracking measures to obtain a deeper understanding of their underlying processes. We describe the issues related to the theoretical proposals on AB and propose research avenues to test them. Four experimental axes are proposed, respectively, related to the determination of (a) the genuine nature of the mechanisms underlying AB; (b) their stability over the disease course; (c) their specificity to alcohol-related stimuli and (d) their reflexive or controlled nature.

CONCLUSIONS

This in-depth exploration of the available knowledge related to AB in SAUD, and of its key limitations, highlights the theoretical and clinical interest of our innovative experimental perspectives capitalizing on eye-tracking measures.

Unseen food images capture the attention of hungry viewers: Evidence from event-related potentials

Motivationally relevant visual targets appear to capture visuospatial attention. This capture is evident behaviorally as faster and more accurate responses, and neurally as an enhanced-amplitude of the N2pc - an index of spatial attention allocation, which is observed even when observers are unaware of the target. In the case of reinforcers such as food or substances of dependence, it is likely that the motivational state of craving accompanying deprivation potentiates this capture. The automaticity of such attentional capture by reward-associated stimuli, as well as its possible interaction with craving, is as yet not completely understood, though it is likely a major explanatory factor in motivated behaviors. For the present experiment, participants completed two EEG recording sessions: one just after eating lunch (sated/non-craving), and the other following a minimum 12-h period of fasting (hungry/craving). For both sessions, participants identified food- and clothing-related targets embedded in an object-substitution masking paradigm, which yielded trials of full target visibility, as well as trials for which targets were present but undetected. Although masking equally disrupted visual awareness of both classes of targets as measured behaviorally, a three-way hunger by visibility by target interaction was observed in the neural data, with unseen food targets eliciting an enhanced N2pc. Interestingly, this subliminal attentional capture by food-related items was observed only during the "hungry" session. No such capture was evident under conditions of full visibility. These findings indicate that attentional capture by food-related images, and reflected in enhancements of the N2pc, is spurred by hunger, and that this effect can be viewed as automatic, or independent of explicit awareness of food-relevant target content.

The role of the vestibular system in value attribution to positive and negative reinforcers

Somatic inputs originating from bioregulatory processes can guide cognition and behavior. One such bodily signal, mostly overlooked so far, is represented by visuo-vestibular coupling and its alteration, which in extreme cases may result in motion sickness. We argued that the inherently perturbed interoceptive state that follows can be a powerful determinant of human motivated behavior, resulting in a blunted response to appetitive stimuli and an exaggerated response to noxious ones. We sought to assess such differential impact of visuo-vestibular mismatches on value through a task involving conflict monitoring. We therefore administered to 42 healthy participants a modified version of the Flankers task, in which distractors (arrows, pointing in either a congruent or incongruent direction) signaled the availability of monetary incentives (gains, losses, or neutral trials). While performing the task, participants received either galvanic vestibular stimulation (GVS), or sham stimulation. We have found impaired behavioral performances when value, which was attached to task-irrelevant information, was at stake. Gains and losses, interestingly, dissociated, and only the latter caused enhanced interference costs in the task, suggesting that negative incentives may be more effective in capturing human attention than positive ones. Finally, we have found some weak evidence for GVS to further increase the processing of losses, as suggested by even larger interference costs in this condition. Results were, however, overall ambiguous, and suggest that much more research is needed to better understand the link between the vestibular system and motivation.

What is the role of stress cardiovascular reactivity in health behaviour change? A systematic review, meta-analysis and research agenda

OBJECTIVE

The stress reactivity hypothesis posits that the extremes of exaggerated and low or blunted cardiovascular reactivity (CVR) to stress may lead to adverse health outcomes via psychophysiological pathways. A potential indirect pathway between CVR and disease outcomes is through health-related behaviour and behaviour change. However, this is a less well understood pathway. Design: A registered systematic review was undertaken to determine the association between cardiovascular reactivity (CVR) and health behaviour change, as well as identify mediators and moderators. Eight papers that met the inclusion criteria, focused on smoking cessation and weight loss, were identified. Results: Pooling data from studies exploring the prospective relationship between CVR (as systolic blood pressure) and smoking cessation found that exaggerated CVR was associated with smoking relapse (Hedges' g = 0.39, SE = 0.00, 95% CI 0.38 - 0.40, p < .001; I2 = 0%; N = 257) but did not find evidence that CVR responses were associated with changes in weight. In order to advance our understanding of reactivity as a modifiable determinant of health behaviour change, our review recommends exploring the association between CVR and other health behaviours, to determine the influence of blunted reactivity versus low motivational effort identify mediators and moderators and determine the focus of interventions.

Eye tracking of smoking-related stimuli in tobacco use disorder: A proof-of-concept study combining attention bias modification with alpha-transcranial alternating current stimulation

BACKGROUND

Tobacco use disorder (TUD) is characterized by the presence of an attentional bias (AB) towards smoking-related stimuli. We investigated whether combining an AB modification paradigm (ABM) with transcranial alternating current stimulation (tACS) applied over the dorsolateral prefrontal cortex (DLPFC) reduces the AB towards smoking-related stimuli, as well as craving level and impulsive choices.

METHODS

In a sham-controlled, crossover preliminary study, 19 subjects with TUD received two stimulation arms: 1) active tACS (10 Hz, 2 mA, 30 min) combined with ABM and 2) sham tACS combined with ABM, in a randomized order, separated by one week. AB towards smoking cues during passive observation of smoking and neutral cues was assessed with an eye-tracking device and reactions times at a visual-probe task. Craving level was measured with the Questionnaire of Smoking Urges. Impulsive choices were assessed with the delay discounting task.

RESULTS

Active tACS combined with ABM reduced the amount of time spent looking at smoking-related pictures (p = 0.03), prevented the increase of self-reported desire to smoke (p = 0.026), and reduced the proportion of impulsive choices (p = 0.049), compared to sham tACS combined with ABM. No significant effects were reported on other craving dimensions and on AB based on reaction times.

CONCLUSIONS

These preliminary findings suggest that combining tACS with ABM may help smokers who wish to quit by reducing the desire to smoke, attention to smoking-cues, and impulsive decision-making.

(Neuro)therapeutic Approaches in the Field of Alcohol Use Disorders

Purpose of Review

Alcohol use disorder (AUD) is a burdening chronic condition that is characterized by high relapse rates despite severe negative consequences. There has been a recent emergence of interest in (neuro)therapeutic intervention strategies that largely involve the detrimental change in mechanisms linked to addiction disorders. Most prominently, the latter include habitual decision-making, cue-induced behavioral tendencies, as well as the amplifying effects of stressful events on drinking behavior. This article discusses these learning mechanisms and modification thereof as possible targets of (neuro)therapeutic interventions for AUD.

Recent Findings

Psychological therapies that target dysregulated neurocognitive processes underlying addictive behavior may hold promise as effective treatments for AUD.

Summary

Despite the progression in psychological and neuroscience research in the field of AUD, many behavioral interventions fail to systematically integrate and apply such findings into treatment development. Future research should focus on the targeted modification of the aforementioned processes.

Craving is everything: An eye-tracking exploration of attentional bias in binge drinking

BACKGROUND

Attentional bias towards alcohol-related stimuli is a core characteristic of severe alcohol use disorders (AUD), directly linked to clinical variables (e.g. alcohol consumption, relapse). Nevertheless, the extent of this bias in subclinical populations remains poorly documented. This is particularly true for binge drinking, an alcohol consumption pattern highly prevalent in youth, characterised by an alternation between excessive intakes and withdrawal periods.

AIMS

We used eye-tracking to: (a) measure attentional bias in binge drinking, (b) determine its time course by dissociating early/late processing stages, (c) clarify its specificity for alcohol-related stimuli compared to other appetitive stimulations and (d) explore its modulation by current craving intensity.

METHODS

Binge drinkers (n=42) and matched controls (n=43) performed a visual probe task, requiring visual targets preceded by pairs of pictures to be processed, with three conditions (i.e. alcohol vs. soft drink, alcohol vs. high-calorie food, high-calorie food vs. low-calorie food).

RESULTS

No group difference was observed for early processing (i.e. first area of interest visited). Dwell times highlighted a bias towards soft drinks and healthy food among controls, without any global bias towards alcohol in binge drinkers. Centrally, a comparison of binge drinkers with low versus high current craving intensity indicated that binge drinking was associated with a bias towards alcohol and high-calorie food only in the presence of a high craving towards these stimuli.

CONCLUSION

Attentional bias towards alcohol reported in severe AUD is only found in binge drinkers in the presence of high craving and is generalised to other appetitive cues.

Baclofen modulates cardiovascular responses to appetitive cues in treatment-seeking alcohol use disorder individuals

OBJECTIVE

To assess whether baclofen-treated alcohol dependent participants show different subjective and psychophysiological responses to appetitive cues during an alcohol cue reactivity task compared to placebo, and whether these responses are associated with prospective drinking outcomes.

METHODS

Forty-two alcohol dependent participants (placebo: n = 12, low-dose baclofen [30 mg/day] n = 18, high-dose baclofen [75 mg/day]: n = 12) completed an alcohol cue reactivity task, whereby water and alcohol beverage cues were presented, with subsequent recovery periods, and subjective alcohol craving and psychophysiological indices (skin conductance; cardiovascular measures: heart rate, high-frequency heart rate variability) were recorded.

RESULTS

High-dose baclofen-treated participants showed both overall cue reactivity to water and alcohol cues and greater recovery effects during recovery periods, revealed by high-frequency heart rate variability, when compared to low-dose- and placebo-treated participants. There were no medication effects on subjective craving. In high-dose baclofen participants only, there was a predictive effect of lower baseline heart rate variability and fewer post-test percentage of heavy drinking days.

CONCLUSION

There was a dose-specific rescuing effect of high-dose baclofen on the dynamic modulation of cardiovascular responses to eliciting cues. Investigation of treatment responses using psychophysiological techniques may elucidate baclofen's mechanisms of action, and identify subgroups amenable to treatment.

Heart Rate Variability, Cue-Evoked Ventromedial Prefrontal Cortical Response, and Problem Alcohol Use in Adult Drinkers

BACKGROUND

Many studies employed cue exposure paradigms to investigate the neural processes underlying cue-elicited alcohol craving. Cue exposure elicits robust autonomic reactivity. However, whether or how cue-elicited autonomic response relates to the severity of alcohol misuse and the neural bases underlying the potential relationship remain unclear.

METHODS

We examined cue-related brain activations in association with heart rate variability, as indexed by the root mean square of the successive differences (RMSSD), during alcohol versus neutral cue blocks in 50 adult alcohol drinkers (24 men). Imaging and heart rate variability data were collected and processed with published routines. Mediation analyses were conducted to examine the interrelationship between regional activities, cue-elicited changes in RMSSD, and the severity of problem alcohol use, as assessed with the Alcohol Use Disorders Identification Test (AUDIT).

RESULTS

The results showed higher RMSSD during alcohol than during neutral cue exposures, with alcohol (vs. neutral) cue-evoked RMSSD positively correlated with AUDIT score. Further, alcohol (vs. neutral) cue-elicited activity in the ventromedial prefrontal cortex was negatively correlated both with increases in RMSSD and with the AUDIT score. Mediation analyses suggested that the RMSSD mediated the relationship between ventromedial prefrontal cortex cue activity and the AUDIT score.

CONCLUSIONS

These findings substantiate the neural correlates of the presumably parasympathetic response during alcohol cue exposure and the interrelationship among ventromedial prefrontal cortex activity, autonomic response, and problem alcohol use.

Alcohol Use Disorder Interventions Targeting Brain Sites for Both Conditioned Reward and Delayed Gratification

Alcohol use disorder is a destructive compulsion characterized by chronic relapse and poor recovery outcomes. Heightened reactivity to alcohol-associated stimuli and compromised executive function are hallmarks of alcohol use disorder. Interventions targeting these two interacting domains are thought to ameliorate these altered states, but the mutual brain sites of action are yet unknown. Although interventions on alcohol cue reactivity affect reward area responses, how treatments alter brain responses when subjects exert executive effort to delay gratification is not as well-characterized. Focusing on interventions that could be developed into effective clinical treatments, we review and identify brain sites of action for these two categories of potential therapies. Using activation likelihood estimation (ALE) meta-analysis, we find that interventions on alcohol cue reactivity localize to ventral prefrontal cortex, dorsal anterior cingulate, and temporal, striatal, and thalamic regions. Interventions for increasing delayed reward preference elicit changes mostly in midline default mode network regions, including posterior cingulate, precuneus, and ventromedial prefrontal cortex-in addition to temporal and parietal regions. Anatomical co-localization of effects appears in the ventromedial prefrontal cortex, whereas effects specific to delay-of-gratification appear in the posterior cingulate and precuneus. Thus, the current available literature suggests that interventions in the domains of cue reactivity and delay discounting alter brain activity along midline default mode regions, specifically in the ventromedial prefrontal cortex for both domains, and the posterior cingulate/precuneus for delay-of-gratification. We believe that these findings could facilitate targeting and development of new interventions, and ultimately treatments of this challenging disorder.

Memory Retrieval-Extinction Combined With Virtual Reality Reducing Drug Craving for Methamphetamine: Study Protocol for a Randomized Controlled Trial

BACKGROUND

Relapse, often precipitated by drug-associated cues that evoke craving, is a key problem in the treatment of methamphetamine use disorder (MUD). Drug-associated memories play a major role in the maintenance of relapse. Extinction training is a common method for decreasing drug craving by suppressing drug-associated memories. However, the effects are often not permanent, which is evident in form of spontaneous recovery or renewal of cue-elicited responses. Based on memory reconsolidation theory, the retrieval-extinction (R-E) paradigm may be more effective in decreasing spontaneous recovery or renewal responses than extinction. After the original memory reactivated to a labile state, extinction will be introduced within the reconsolidation window, thereby updating drug-associated memories. However, there are still some controversial results, which suggest that the reactivation of drug-associated memories and the 10 min-6 h of limited time window are two main elements in the R-E protocol. Virtual reality (VR) is supposed to promote memory reactivation by providing vivid drug-related stimuli when compared with movies.

OBJECTIVE

The aim of this study is to examine the effectiveness of R-E training combined with VR on reducing spontaneous recovery or renewal of cue-elicited responses, in comparison to extinction, R-E training provided outside the time window of 6 h and R-E training retrieved using videos, in methamphetamine abusers.

METHODS

The study is a parallel matched controlled study including 95 participants with MUD. Participants will be randomly assigned to either a R-10 min-E group (methamphetamine-related cues retrieval in VR followed by extinction after 10 min) or a NR-10 min-E group (neutral cues retrieval in VR followed by extinction after 10 min) or a R-6 h-E group (methamphetamine-related cues retrieval in VR followed by extinction after 6 h) or a RV-10 min-E group (methamphetamine-related cues retrieval in videos followed by extinction after 10 min). Cue-evoked craving and reactivity will be assessed at pre-test and at 1 day, 1 week, 1 month, and 6-month post-tests.

DISCUSSION

To our knowledge, this study will probably be the first study to examine the efficacy of R-E training combined with VR to reduce cue-evoked responses in people with MUD. This innovative non-pharmacological intervention targeting drug-associated memories may provide significant clinical implications for reducing relapse, providing the study confirms its efficacy.

CLINICAL TRIAL REGISTRATION

The trial is registered with Chinese Clinical Trial Registry at 17 October 2018, number: ChiCTR1800018899, URL: http://www.chictr.org.cn/showproj.aspx?proj=30854.

Evidence for incentive salience sensitization as a pathway to alcohol use disorder

The incentive salience sensitization (ISS) theory of addiction holds that addictive behavior stems from the ability of drugs to progressively sensitize the brain circuitry that mediates attribution of incentive salience (IS) to reward-predictive cues and its behavioral manifestations. In this article, we establish the plausibility of ISS as an etiological pathway to alcohol use disorder (AUD). We provide a comprehensive and critical review of evidence for: (1) the ability of alcohol to sensitize the brain circuitry of IS attribution and expression; and (2) attribution of IS to alcohol-predictive cues and its sensitization in humans and non-human animals. We point out gaps in the literature and how these might be addressed. We also highlight how individuals with different alcohol subjective response phenotypes may differ in susceptibility to ISS as a pathway to AUD. Finally, we discuss important implications of this neuropsychological mechanism in AUD for psychological and pharmacological interventions attempting to attenuate alcohol craving and cue reactivity.

Heart rate variability as a potential biomarker for alcohol use disorders: A systematic review and meta-analysis

BACKGROUND

Alcohol use disorders (AUDs) have been found to be associated with elevated cardiovascular risk. The autonomic nervous system is considered to play a role in this association. Heart rate variability (HRV) has been employed to measure parasympathetic activity in AUDs patients in some studies; however, the results are not consistent, and the adopted HRV indices vary across studies. A meta-analysis should be helpful for clarifying this topic.

METHODS

We gathered studies about measuring HRV in AUDs patients and healthy participants from databases. HRV was analyzed in several ways: parasympathetic function in hierarchical order (main analysis), total variability, and specific parasympathetic indices. Specific parasympathetic indices were further separated into high-frequency power (HF) and root mean square of the successive differences (RMSSD). For comparing the above values in patients with AUDs and in healthy individuals, we adopted the random effects model to calculate the standardized mean difference.

RESULTS

Of the 144 screened studies, 15 were included in the quantitative analysis. In the comparison of parasympathetic function in hierarchical order, HRV in AUDs patients was significantly lower than in healthy individuals (Hedges'g = -0.4301, 95% CI [-0.7601 to -0.1000], p=0.0106, I² = 83.8%). Regarding total variability and RMSSD, AUDs patients also had significantly lower values than healthy controls. However, the differences of specific parasympathetic indices and HF were not significantly different.

CONCLUSION

Our results support the view that AUDs patients have reduced parasympathetic activity. Total variability and RMSSD are suitable indices for presenting reduced HRV in patients with AUDs.

Craving Mediates the Relation Between Impulsivity and Alcohol Consumption Among University Students

BACKGROUND AND OBJECTIVES

The relationship between impulsivity and craving in severe alcohol use disorders is well established, but the presence and characteristics of this link in University students are still to be established. The present study aims to better understand the relationship between impulsivity and craving in university students and to determine the influence of these variables on alcohol consumption characteristics.

METHODS

A large sample of university students (N = 1055, mean age: 20.9 years; 713 women) completed an online questionnaire to evaluate alcohol use, impulsivity, and craving.

RESULTS

Linear regression analysis demonstrated that the compulsive dimensions of craving (P < .001), sensation seeking (P < .001), and lack of premeditation (P < .001) constitute strong predictors of current consumption. A receiver operating characteristic (ROC) curve analysis determined the threshold level above which craving intensity can identify specific high-risk populations. A mediation analysis showed that craving has a partial mediator effect on the impact of impulsivity on alcohol consumption for this population (37,8%, P < .001).

DISCUSSION AND CONCLUSIONS

The sensation seeking and lack of premeditation dimensions of impulsivity, coupled with compulsive craving, are efficient predictors of excessive alcohol consumption for university students. The partial mediator effect of craving is important in terms of characterizing the relationship between impulsivity and alcohol consumption.

SCIENTIFIC SIGNIFICANCE

Our study centrally shows that the interaction between elevated levels of impulsivity and craving constitute a crucial risk factor for alcohol consumption in university students, and should thus constitute a target for primary prevention programs (Am J Addict 2019;00:00-00).

Alcohol use disorder relapse factors: A systematic review

A relapsing-remitting course is very common in patients with an Alcohol Use Disorder (AUD). Understanding the determinants associated with alcohol resumption remains a formidable task. This paper examines relapse determinants based on a systematic review of recent alcohol literature (2000-2019). Relevant databases were consulted for articles that contained information about specific relapse determinants and reported statistical significance of each relapse determinant in predicting relapse. Relapse was broadly defined based on the characterization in the included articles. From the initial identified 4613 papers, a total of 321 articles were included. Results encompass multiple relapse determinants, which were ordered according to biopsychosocial and spiritual categories, and presented, using a descriptive methodology. Psychiatric co-morbidity, AUD severity, craving, use of other substances, health and social factors were consistently significantly associated with AUD relapse. Conversely, supportive social network factors, self efficacy, and factors related to purpose and meaning in life, were protective against AUD relapse. Despite heterogeneity in different methods, measures, and sample characteristics, these findings may contribute to a better therapeutic understanding in which specific factors are associated with relapse and those that prevent relapse. Such factors may have a role in a personalized medicine framework to improve patient outcomes.

Baseline resting heart rate variability predicts post-traumatic stress disorder treatment outcomes in adults with co-occurring substance use disorders and post-traumatic stress

Post-traumatic stress disorder (PTSD) symptoms are highly prevalent among individuals with substance use disorders (SUD), presenting a difficult-to-treat, complex comorbidity. Prognostic factors for treatment outcomes may characterize heterogeneity of the treated population and/or implicate mechanisms of action that are salient for improving treatments. High frequency heart rate variability (HF-HRV) is a suggested biomarker for emotion regulation-the ability to generate appropriate emotional responses via the influence of the parasympathetic nervous system on the heart. This initial study investigated the utility of baseline resting HF-HRV for predicting PTSD symptoms and substance use outcomes following treatment of 37 SUD participants with comorbid PTSD symptoms. Participants completed either standard cognitive- behavioral therapy (CBT) for SUD or a novel treatment of integrated post-traumatic stress and substance use that combined CBT for SUD with cognitive processing therapy for PTSD. Analyses demonstrated that higher HF-HRV predicted greater reduction in PTSD symptoms following both types of treatment. This suggests prognostic value of HF-HRV as a predictor of PTSD treatment outcomes; those with poorer autonomic emotional regulation may not respond as well to psychotherapy in general. This hypothesis-generating analysis identifies a putative biomarker that might have utility in treatment prediction.

Preliminary examination of the orexin system on relapse-related factors in cocaine use disorder

RATIONALE

Current evidence and literature reviews provide a strong justification for examining the orexin receptor (OXR) system as a therapeutic target in substance use disorders, including cocaine and other psychostimulants.

OBJECTIVES

In this preliminary, proof-of-concept examination of orexin modulation in humans with cocaine use disorder, we measured changes in domains tied to relapse: stress, sleep, cue reactivity, and inhibitory control. Additionally, mood symptoms (anxiety, depression), medication compliance, and side effects were assessed.

METHODS

Twenty non-treatment seeking subjects with cocaine use disorder (CUD) received either the OX₁R / OX₂R antagonist suvorexant PO or placebo at 10 PM daily for two weeks (10 mg week 1, 20 mg week 2). Using psychometrics, smart-watch actigraphy, a cold-pressor stress challenge, and eye-tracking technology, the following domains were examined: sleep, stress/anxiety, cue-reactivity (attentional bias, craving), and inhibitory control. Psychometric data were collected every M/W/F (7 time points). Laboratory data were collected weekly (3 time points).

RESULTS

Bayesian and frequentist generalized linear models were employed in parallel to examine the effects of suvorexant compared to placebo, with a Bayesian posterior probability threshold >80% as evidence of a signal for suvorexant. Notable results favoring suvorexant over placebo included fewer total anti-saccade errors, improved sleep actigraphy (sleep/awake periods), pre/post cold-pressor change in heart rate and salivary cortisol (all posterior probabilities >94%), and craving (posterior probability >87%).

CONCLUSIONS

Initial but restricted evidence is provided supporting the orexin system as a modulator of relapse-related processes in cocaine use disorder. Baseline differences in the main outcome variables were not experimentally controlled and differences in craving were observed at baseline. This, in combination with a limited sample size, constrain the nature of the project. The results may serve to inform more comprehensive future research.

Cardiorespiratory Fitness Predicts Greater Vagal Autonomic Activity in Drug Users Under Stress

While drug use has been shown to impair cardiac autonomic regulation, exercise might overcome some of the damage. Herein, we describe how individuals with substance use disorder (SUD) have their heart rate variability (HRV) and drug-related behaviors negatively affected in response to a stressor. However, we show how cardiorespiratory fitness may attenuate those impairments in autonomic control. Fifteen individuals with SUD were matched with 15 non-SUD individuals by age, weight, height, and fitness level, and had their HRV responses under stress induced by the Cold Pressor Test (CPT). The SUD group had lower mean of R-R intervals before and after the CPT when compared with the non-SUD group. In addition, in individuals with SUD, higher cardiorespiratory fitness level predicted greater vagal activity before, during, and after CPT. Moreover, for individuals with SUD, days of abstinence predicted greater mean of R-R intervals during recovery from the CPT. Finally, years of drug use negatively predicted mean of R-R intervals during recovery. Thus, our results suggest that chronic drug use impairs cardiac autonomic regulation at rest and after a physical stress. However, cardiorespiratory fitness might attenuate these impairments by increasing vagal autonomic activity.

Sign-tracking behavior is difficult to extinguish and resistant to multiple cognitive enhancers

The attribution of incentive-motivational value to drug-related cues underlies relapse and craving in drug addiction. One method of addiction treatment, cue-exposure therapy, utilizes repeated presentations of drug-related cues in the absence of drug (i.e., extinction learning); however, its efficacy has been limited due to an incomplete understanding of extinction and relapse processes after cues have been imbued with incentive-motivational value. To investigate this, we used a Pavlovian conditioned approach procedure to screen for rats that attribute incentive-motivational value to reward-related cues (sign-trackers; STs) or those that do not (goal-trackers; GTs). In Experiment 1, rats underwent Pavlovian extinction followed by reinstatement and spontaneous recovery tests. For comparison, a separate group of rats underwent PCA training followed by operant conditioning, extinction, and tests of reinstatement and spontaneous recovery. In Experiment 2, three cognitive enhancers (sodium butyrate, D-cycloserine, and fibroblast growth factor 2) were administered following extinction training to facilitate extinction learning. STs but not GTs displayed enduring resistance to Pavlovian, but not operant, extinction and were more susceptible to spontaneous recovery. In addition, none of the cognitive enhancers tested affected extinction learning. These results expand our understanding of extinction learning by demonstrating that there is individual variation in extinction and relapse processes and highlight potential difficulties in applying extinction-based therapies to drug addiction treatment in the clinic.

Theoretical implications and clinical support for heart rate variability biofeedback for substance use disorders

Heart rate variability (HRV) biofeedback is an accessible, cost-effective intervention that has demonstrated clinical value for numerous physical and mental health conditions; however, research on HRV biofeedback in substance use disorders (SUD) is in its nascence. We argue that HRV biofeedback may be particularly beneficial as an adjunct treatment for SUD by targeting bodily systems that are known to be disrupted by chronic substance use and are not historically the focus of psychosocial or pharmacological SUD treatment approaches. In addition to advocating for HRV biofeedback applications in SUD, we identify several gaps within the existing experimental literature, and propose new studies that could accelerate understanding of how and for whom HRV biofeedback is most likely to promote positive behavior change.

Pupillary reactivity to alcohol cues as a predictive biomarker of alcohol relapse following treatment in a pilot study

RATIONALE

Identifying the predictors of relapse in detoxified alcohol-dependent patients is crucial for effective surveillance procedures and the optimization of treatment. Physiological measures such as functional MRI activity and heart rate variability have been shown as potential markers of relapse prediction.

OBJECTIVES

Our aim was to assess differential pupillary reactions to alcohol-related cues as an objective physiological candidate predictor of relapse.

METHODS

We examined the relationship between cue-elicited pupillary reactions to alcohol stimuli and luminance-controlled neutral stimuli in 21 detoxified alcohol-dependent patients and subsequent relapse outcome at a 4-month follow-up.

RESULTS

Differential pupillary dilation to alcohol stimuli as compared to neutral stimuli at 150 to 250 ms after stimulus onset substantially improved the model prediction of relapse outcome (additional 27% of variance) beyond that achieved from five standardized questionnaires on alcohol craving, alcohol use, problematic use severity, depressive tendencies, and duration of abstinence (47% of variance). In contrast, alcohol craving did not improve relapse model prediction.

CONCLUSIONS

This pilot study shows that alcohol-dependent patients with greater pupillary dilation to alcohol stimuli are more vulnerable to relapse, and that pupillometry presents as an important tool for addiction science.

Knowledge about the predictive value of reward conditioned stimuli modulates their interference with cognitive processes

Stimuli conditioned with a substance can generate drug-approach behaviors due to their acquired motivational properties. According to implicit theories of addiction, these stimuli can decrease cognitive control automatically. The present study (n = 49) examined whether reward-associated stimuli can interfere with cognitive processes in the absence of knowledge about stimulus–outcome contingencies. Conditioned stimuli (CS) were paired with high-reward (HR) or low-reward (LR) probabilities of monetary reward using a Pavlovian learning task. Participants were categorized as Aware or Unaware of contingencies using a Bayesian analysis. CS were then used as task-irrelevant distractors in modified flanker and N-back tasks. Results show HR CS can generate increased interference in the flanker task for participants Unaware of contingencies, contributing further evidence for the existence of implicit Pavlovian conditioning. For the N-back task, working memory performance was affected by HR CS, albeit only for Aware participants. These results suggest that CS can interfere implicitly with cognitive processes in a similar way to drug-related stimuli. Such an effect could occur in a stimulus-driven fashion, devoid of top-down goal-directedness. These findings have implications for the conceptualization and study of implicit processes in addiction and highlights the necessity to reconsider the measurement of such phenomena.

Autonomic and affective mediators of the relationship between mindfulness and opioid craving among chronic pain patients

Prescription opioid misuse among chronic pain patients is undergirded by self-regulatory deficits, affective distress, and opioid-cue reactivity. Dispositional mindfulness has been associated with enhanced self-regulation, lower distress, and adaptive autonomic responses following drug-cue exposure. We hypothesized that dispositional mindfulness might serve as a protective factor among opioid-treated chronic pain patients. We examined heart-rate variability (HRV) during exposure to opioid cues and depressed mood as mediators of the association between dispositional mindfulness and opioid craving. Data were obtained from a sample of chronic pain patients (N = 115) receiving long-term opioid pharmacotherapy. Participants self-reported opioid craving and depression, and HRV was measured during an opioid-cue dot-probe task. Dispositional mindfulness was significantly positively correlated with HRV, and HRV was significantly inversely associated with opioid craving. Dispositional mindfulness was significantly negatively correlated with depression, and depression was significantly positively correlated with opioid craving. Path analysis revealed significant indirect effects of dispositional mindfulness on craving through both HRV and depression. Dispositional mindfulness may buffer against opioid craving among chronic pain patients prescribed opioids; this buffering effect may be a function of improved autonomic and affective responses. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Identifying Triggers of Alcohol Craving to Develop Effective Virtual Environments for Cue Exposure Therapy

Background: Many studies have indicated that alcohol craving is a core mechanism in the acquisition, maintenance, and precipitation of relapse in alcohol use disorder (AUD). A common treatment approach in AUD is cue exposure therapy (CET). New technologies like virtual reality (VR) have the potential to enhance the effectiveness of CET by creating realistic scenarios in naturalistic environments. In this study, we aimed to determine relevant triggers of alcohol craving in patients with AUD.

Methods: We enrolled 75 outpatients diagnosed with AUD according to the DSM-5 criteria Participants completed the Alcohol Use Disorder Identification Test and a self-administered questionnaire to assess alcohol craving. The variables included in the craving questionnaire were as follows: presence of others, situations, time of the day, day of the week, mood, and type of alcoholic beverage.

Results: Greater levels of alcohol craving were seen in many situations, including being at a party, in a restaurant, in a bar or pub, and at home. Drinking alone and drinking with two or more friends were equally associated with higher levels of craving. Drinking at night and drinking at weekends also emerged as triggers for alcohol craving. Emotional states like anxiety or tension, sadness, stress, frustration, or irritability were highly associated with urges to drink alcohol. The alcoholic drinks most highly associated with increased levels of craving were beer, wine, and whisky. Gender and age implications were discussed.

Conclusion: This study is part of a larger project aiming to develop and validate CET based on VR technology for patients with AUD who are resistant to classical treatment. The identified triggers have been used to develop relevant VR environments for CET, and further research is ongoing to implement our findings.

Perceptions of Alcohol Advertising Vary Based on Psychological Characteristics

BACKGROUND

The alcohol industry recognizes children and pregnant women as population sub-groups vulnerable to the effects of alcohol marketing. Research indicates that heavy alcohol users are also potentially vulnerable to alcohol marketing. The purpose of the current study is to determine if sub-groups defined by psychological characteristics should be classified as potentially vulnerable as well.

METHODS

College students (n = 326) from two northeast schools were recruited to complete a survey containing questions on demographics, alcohol use, and psychological characteristics (alcohol expectancies, alcohol dependence, sensation seeking traits, and past delinquent behaviors). Additionally, after viewing each of five alcohol ads (4 television and 1 magazine), participants answered questions about their perceptions of alcohol consumption, responsible drinking, excessive drinking, and appeal of the ads. Main effects were assessed using hierarchical linear modeling, with adjustment for age, sex, race, ethnicity, and AUDIT score.

RESULTS

Alcohol expectancies (p < .001), particularly the social and physical pleasure and social expressiveness sub-scales, and sensation seeking traits (p = .002) were positively associated with alcohol ad appeal. Alcohol dependence symptoms, specifically impaired control and tolerance, were positively associated with perceptions of responsible drinking (p = .035), even though mean perceived number of drinks consumed met the definition of binge drinking.

CONCLUSIONS

Individuals with positive alcohol expectancies, sensation seeking traits, and alcohol dependence may be vulnerable to alcohol advertising and marketing. Because alcohol advertising often contains content that can serve as a cue or reinforce to drink, specific regulations may be needed to prevent alcohol-related harm from occurring in these sub-populations.

A Patient-Tailored Evidence-Based Approach for Developing Early Neuropsychological Training Programs in Addiction Settings

Substance use disorders (SUDs) are associated with impairments of cognitive functions, and cognitive training programs are thus rapidly developing in SUD treatment. However, neuropsychological impairments observed early after withdrawal (i.e., early impairments), that is, approximately in the first six months, may be widespread. Consequently, it might not be possible to train all the identified early impairments. In these situations, we propose that the priority of cognitive training should be given to the early impairments found to be associated with early dropout or relapse (i.e., relapse-related impairments). However, substance-specific relapse-related impairments have not been singled out among all early impairments so far. Using a systematic literature search, we identified the types of established early impairments for all SUDs, and we assessed the extent to which these early impairments were found to be associated with relapse-related impairments. All cognitive functions were investigated according to a classification based on current neuropsychological models, distinguishing classical cognitive, substance-bias, and social cognition systems. According to the current evidence, demonstrated relapse-related impairments in alcohol use disorder comprised impulsivity, long-term memory, and higher-order executive functions. For cannabis use disorder, the identified relapse-related impairments were impulsivity and working memory. For stimulant use disorder, the identified relapse-related impairments were attentional abilities and higher-order executive functions. For opioid use disorder, the only identified relapse-related impairments were higher executive functions. However, many early impairments were not explored with respect to dropout/relapse, particularly for stimulant and opioid use disorders. The current literature reveals substance-specific relapse-related impairments, which supports a pragmatic patient-tailored approach for defining which early impairments should be prioritized in terms of training among patients with SUDs.

Distress tolerance: Associations with trauma and substance cue reactivity in low-income, inner-city adults with substance use disorders and posttraumatic stress

Cue reactivity has great potential to advance our understanding of posttraumatic stress disorder (PTSD), substance use disorder (SUD), and PTSD/SUD comorbidity. The present investigation examined distress tolerance (DT) with regard to trauma and substance cue reactivity. Participants included 58 low-income, inner-city adults (49.1% women; M_age = 45.73, SD = 10.00) with substance dependence and at least 4 symptoms of PTSD. A script-driven cue reactivity paradigm was utilized. Four DT measures were administered, including the Distress Tolerance Scale (DTS), Mirror-Tracing Persistence Task (MTPT), Breath-Holding Task (BH), and Paced Auditory Serial Addition Task (PASAT). Lower DT, as indexed by MTPT duration, was significantly predictive of greater levels of self-reported substance cravings/urges in response to trauma cues, above and beyond covariates. Lower DTS scores predicted lower levels of self-reported control/safety ratings in response to substance cues. None of the DT indices was significantly predictive of heart rate variability. Clinical and research implications are discussed. (PsycINFO Database Record

Heart rate variability in alcohol use: A review

BACKGROUND

Prior studies have shown that resting heart rate variability (HRV) is reduced in those with alcohol use disorders (AUD). However, HRV following an acute stressful stimulus (reactive HRV), and the relationship between resting or reactive HRV and drinking, craving and relapse in AUD have received less attention.

METHODS

Studies using HRV in relationship to acute or chronic alcohol consumption were included in this review. Manuscripts that related to alcohol in the context of cardiovascular disease were excluded.

RESULTS

Thirty-three articles were included and findings are presented in healthy social drinkers, moderate/heavy drinkers without AUD and individuals with AUD. Results on resting and reactive HRV were presented separately. Acute alcohol reduced resting HRV in healthy subjects but healthy controls had higher resting HRV then AUD subjects and moderate/heavy drinkers (in some studies). Resting HRV improved in AUD subjects only after at least 4 months of abstinence. AUD subjects had higher reactive HRV scores when compared to controls. In AUD subjects increased reactivity was related to more craving, faster relapse and more negative mood. Reactive HRV showed slower improvement with abstinence in AUD subjects.

CONCLUSIONS

Chronic, heavy alcohol has a negative effect on the autonomic nervous system and may be a sensitive biomarker of craving and relapse.