The effect of alcohol priming on neural markers of alcohol cue-reactivity

Examining Audiences' Psychological Reactance to Christian-Sourced Excessive Alcohol Consumption Messages in the United States

This study experimentally investigated the effect of dogmatic and suggestive language in Christian-sourced excessive alcohol consumption messages among college-aged participants who identify as Christians or non-Christians, as well as the role of perceived similarity with the message source, on their self-reported freedom-threat, psychological reactance, and behavioral intentions to consume alcohol. The results from this study support psychological reactance theory and demonstrate the various message strategies to effectively communicate the negative health effects of excessive alcohol consumption to individuals who identify either as Christians or non-Christians.

Is implicit memory associated with the hippocampus?

According to the traditional memory-systems view, the hippocampus is critical during explicit (conscious) long-term memory, whereas other brain regions support implicit (nonconscious) memory. In the last two decades, some fMRI studies have reported hippocampal activity during implicit memory tasks. The aim of the present discussion paper was to identify whether any implicit memory fMRI studies have provided convincing evidence that the hippocampus is associated with nonconscious processes without being confounded by conscious processes. Experimental protocol and analysis parameters included the stimulus type(s), task(s), measures of subjective awareness, explicit memory accuracy, the relevant fMRI contrast(s) or analysis, and confound(s). A systematic review was conducted to identify implicit memory studies that reported fMRI activity in the hippocampus. After applying exclusion criteria, 13 articles remained for analysis. We found that there were no implicit memory fMRI studies where subjective awareness was absent, explicit memory performance was at chance, and there were no confounds that could have driven the observed hippocampal activity. The confounds included explicit memory (including false memory), imbalanced attentional states between conditions (yielding activation of the default-mode network), imbalanced stimuli between conditions, and differential novelty. As such, not a single fMRI study provided convincing evidence that implicit memory was associated with the hippocampus. Neuropsychological evidence was also considered, and implicit memory deficits were caused by factors known to disrupt brain regions beyond the hippocampus, such that the behavioral effects could not be attributed to this region. The present results indicate that implicit memory is not associated with the hippocampus.

Erotic cue exposure increases physiological arousal, biases choices toward immediate rewards, and attenuates model-based reinforcement learning

Computational psychiatry focuses on identifying core cognitive processes that appear altered across distinct psychiatric disorders. Temporal discounting of future rewards and model-based control during reinforcement learning have proven as two promising candidates. Despite its trait-like stability, temporal discounting may be at least partly under contextual control. Highly arousing cues were shown to increase discounting, although evidence to date remains somewhat mixed. Whether model-based reinforcement learning is similarly affected by arousing cues remains unclear. Here, we tested cue-reactivity effects (erotic pictures) on subsequent temporal discounting and model-based reinforcement learning in a within-subjects design in n = 39 healthy heterosexual male participants. Self-reported and physiological arousal (cardiac activity and pupil dilation) were assessed before and during cue exposure. Arousal was increased during exposure of erotic versus neutral cues both on the subjective and autonomic level. Erotic cue exposure increased discounting as reflected by more impatient choices. Hierarchical drift diffusion modeling (DDM) linked increased discounting to a shift in the starting point bias of evidence accumulation toward immediate options. Model-based control during reinforcement learning was reduced following erotic cues according to model-agnostic analysis. Notably, DDM linked this effect to attenuated forgetting rates of unchosen options, leaving the model-based control parameter unchanged. Our findings replicate previous work on cue-reactivity effects in temporal discounting and for the first time show similar effects in model-based reinforcement learning in a heterosexual male sample. This highlights how environmental cues can impact core human decision processes and reveal that comprehensive modeling approaches can yield novel insights in reward-based decision processes.

Alcohol craving in the natural environment: Moderating roles of cue exposure, drinking, and alcohol sensitivity

Effects of cue exposure and alcohol consumption (e.g., priming doses) on craving for alcohol have been examined in largely separate literature, limiting what is known about their potential interaction. Individuals with low alcohol sensitivity, a known risk factor for alcohol use disorder (AUD), exhibit stronger cue-elicited craving than their higher-sensitivity (HS) peers in both laboratory and real-world contexts. Here, underage drinkers (N = 155) completed a 21-day ecological momentary assessment (EMA) protocol in which they recorded exposure to alcohol cues and levels of craving during both nondrinking and postdrinking moments. Multilevel modeling detected a significant interaction of cue exposure and postdrinking status on craving. Cue-induced craving was increased in postdrinking moments compared to nondrinking moments. Contrary to prediction, cue-elicited increase in craving during nondrinking moments was stronger in participants reporting higher sensitivity to alcohol. In the presence of cues, lower sensitivity was robustly related to craving intensity in the postdrinking state but unrelated to craving during nondrinking moments. Craving during drinking episodes in the natural environment is magnified by the presence of alcohol cues, potentially contributing to the maintenance or acceleration of drinking episodes. Moreover, lower-sensitivity drinkers may be particularly susceptible to the combined effects of cue exposure and postdrinking status on alcohol craving. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The impact of alcohol priming on craving and motivation to drink: a meta-analysis

BACKGROUND AND AIMS

An initial dose of alcohol can motivate-or prime-further drinking and may precipitate (re)lapse and bingeing. Lab-based studies have investigated the alcohol priming effect; however, heterogeneity in designs has resulted in some inconsistent findings. The aims of this meta-analysis were to (i) determine the pooled effect size for motivation to drink following priming, measured by alcohol consumption and craving, and (ii) examine whether design characteristics influenced any priming effect.

METHODS

Literature searches of PsycINFO, PubMed and Scopus in October 2020 (updated October 2021) identified lab-based alcohol priming studies that assessed effect of priming on motivation to drink. A tailored risk-of-bias tool assessed quality of lab-based studies. Random effects meta-analyses were computed on outcome data from 38 studies comparing the effect of a priming dose of alcohol against control on subsequent alcohol consumption/self-reported craving. Study characteristics that might have affected outcomes were design type (within/between-participant), dose of prime, time of motivation assessment, type of control drink (placebo alcohol/soft drink).

RESULTS

Relative to control, alcohol had a small-to-moderate priming effect on subsequent alcohol consumption (standardised mean difference [SMD] = 0.336 [95% CI, 0.171, 0.500]) and craving (SMD = 0.431 [95% CI, 0.306, 0.555]). Aspects of study design differentially affected consumption and craving. The size of the priming dose had no effect on consumption, but larger doses were sometimes associated with greater craving (with craving generally following the blood alcohol curve). Alcohol priming effects for consumption, but not craving, were smaller when compared with placebo, relative to soft drink, control.

CONCLUSIONS

Lab-based alcohol priming studies are a valid paradigm from which to investigate the impact of acute intoxication on alcohol motivation. Designs are needed that assess the impact of acute consumption on motivation to drink in more varied and realistic ways.

Alcohol availability during withdrawal gates the impact of alcohol vapor exposure on responses to alcohol cues

RATIONALE

Chronic intermittent ethanol (CIE) vapor inhalation is a widely used model of alcohol dependence, but the impact of CIE on cue-elicited alcohol seeking is poorly understood.

OBJECTIVE

Here, we assessed the effects of CIE on alcohol-seeking elicited by cues paired with alcohol before or after CIE vapor inhalation.

METHODS

In experiment 1, male and female Long-Evans rats were trained in a discriminative stimulus (DS) task, in which one auditory cue (the DS) predicts the availability of 15% ethanol and a control cue (the NS) predicts no ethanol. Rats then underwent CIE or served as controls. Subsets of each group received access to oral ethanol twice a week during acute withdrawal. After CIE, rats were presented with the DS and NS cues under extinction and retraining conditions to determine whether they would alter their responses to these cues. In experiment 2, rats underwent CIE prior to training in the DS task.

RESULTS

CIE enhanced behavioral responses to cues previously paired with alcohol, but only in rats that received access to alcohol during acute withdrawal. When CIE occurred before task training, male rats were slower to develop cue responses and less likely to enter the alcohol port, even though they had received alcohol during acute withdrawal.

CONCLUSIONS

These results suggest that CIE vapor inhalation alone does not potentiate the motivational value of alcohol cues but that an increase in cue responses requires alcohol experience during acute withdrawal. Furthermore, under some conditions, CIE may disrupt responses to alcohol-paired cues.

How laboratory studies of cigarette craving can inform the experimental alcohol craving literature

Interest in alcohol and other drug craving has flourished over the past two decades, and evidence has accumulated showing that craving can be meaningfully linked to both drug use and relapse. Considerable human experimental alcohol craving research since 2000 has focused on craving as a clinical phenomenon. Self-reported craving to drink typically has served as a catch-all for the craving construct in these studies, whereas few studies have considered craving as a process (or hypothetical construct) that interacts with other phenomena to affect use. In contrast to alcohol, we believe that recently there has been more mechanistic work targeting cigarette craving-related processes. Here, we briefly present a narrative review of studies of acute alcohol craving in humans that have been conducted during the past two decades. We then specify important ways in which alcohol and tobacco differ (e.g., the role of withdrawal), and we note the unique challenges in inducing robust alcohol craving states in the laboratory. Finally, we offer recommendations for how the alcohol field might advance its conceptual understanding of craving by adopting ideas and methods drawn from the smoking research literature. Specifically, we suggest that researchers extend their studies to not only examine the link between alcohol craving and relapse but also to focus on why and, in some instances, how alcohol cravings matter clinically, and the circumstances under which craving especially matters. We propose research to investigate the shifts in alcohol-related cognitive and affective processing that occur during alcohol craving states. Furthermore, we highlight the value of research examining the level of insight that individuals with varying levels of alcohol involvement possess about their own craving-related processing shifts. We believe that laboratory studies can provide rich opportunities to examine conceptual questions about alcohol craving that are central to addiction.

Depicting People in Visual Cues Affects Alcohol Cue Reactivity in Male Alcohol-Dependent Patients

Cue reactivity is often used to study alcohol cues brain responses. Standardized image sets are used, but the effect of viewing people interacting with the alcohol drink remains unclear, which is associated with the factors of alcohol cues that influence the degree of response to alcohol stimuli. The present study used fMRI to investigate the reactivity of alcohol dependence (AD) inpatients to alcohol cues with or without human drinking behavior. Cues with a human interacting with a drink were hypothesized to increase sensorimotor activation. In total, 30 AD inpatients were asked to view pictures with a factorial design of beverage types (alcoholic vs. non-alcoholic beverages) and cue types (with or without drink action). Whole-brain analyses were performed. A correlation analysis was conducted to confirm whether the whole-brain analysis revealed cue-related brain activations correlated with problem drinking duration. The left lingual gyrus showed significant beverage types through cue type interaction, and the bilateral temporal cortex showed significant activation in response to alcohol cues depicting human drinking behavior. The right and left lingual gyrus regions and left temporal cortex were positively correlated with problem drinking duration. Sensorimotor activations in the temporal cortex may reflect self-referential and memory-based scene processing. Thus, our findings indicate these regions are associated with alcohol use and suggest them for cue exposure treatment of alcohol addiction.

Trial-wise exposure to visual emotional cues increases physiological arousal but not temporal discounting

Humans and many animals devalue future rewards as a function of time (temporal discounting). Increased discounting has been linked to various psychiatric conditions, including substance-use-disorders, behavioral addictions, and obesity. Despite its high intra-individual stability, temporal discounting is partly under contextual control. One prominent manipulation that has been linked to increases in discounting is the exposure to highly arousing appetitive cues. However, results from trial-wise cue exposure studies appear highly mixed, and changes in physiological arousal were not adequately controlled. Here we tested the effects of appetitive (erotic), aversive, and neutral visual cues on temporal discounting in 35 healthy male participants. The contribution of single-trial physiological arousal was assessed using comprehensive monitoring of autonomic activity (pupil size, heart rate, electrodermal activity). Physiological arousal was elevated following aversive and in particular erotic cues. In contrast to our pre-registered hypothesis, steepness of temporal discounting was not significantly affected by emotional cues of either valence. Aversive cues tended to increase decision noise. Computational modeling revealed that trial-wise arousal only accounted for minor variance over and above aversive and erotic condition effects, arguing against a general effect of physiological arousal on temporal discounting.

Neurobiological correlates of cue-reactivity in alcohol-use disorders: A voxel-wise meta-analysis of fMRI studies

Altered brain responses to alcohol-associated stimuli are a neural hallmark of alcohol-use disorder (AUD) and a promising target for pharmacotherapy. However, findings in cue-reactivity based functional MRI (fMRI) studies are inconclusive. To investigate the neural substrates of cue-reactivity and their relevance to treatment outcomes, alcohol craving and relapse in AUD patients, we performed five meta-analyses using signed differential mapping software. Our meta-analysis revealed that alcohol cues evoke greater cue-reactivity than neutral cues in the mesocorticolimbic circuit and lower reactivity in the parietal and temporal regions in AUD patients. Compared to controls, AUD individuals displayed hyperactivations in the medial prefrontal cortex and anterior/middle part of the cingulate cortex. After receiving AUD treatment, AUD patients exhibited greater activations in the precentral gyrus but reduced activations in the bilateral caudate nucleus, insula, right DLPFC, and left superior frontal gyrus. No significant results were found in cue-reactivity correlates of alcohol craving and relapse. Our results implicate cue-induced abnormalities in corticostriatal-limbic circuits may underline the pathophysiology of AUD, and have translational value for treatment development.

Association of the OPRM1 A118G polymorphism and Pavlovian-to-instrumental transfer: Clinical relevance for alcohol dependence

BACKGROUND

Pavlovian-to-instrumental transfer (PIT) quantifies the extent to which a stimulus that has been associated with reward or punishment alters operant behaviour. In alcohol dependence (AD), the PIT effect serves as a paradigmatic model of cue-induced relapse. Preclinical studies have suggested a critical role of the opioid system in modulating Pavlovian-instrumental interactions. The A118G polymorphism of the OPRM1 gene affects opioid receptor availability and function. Furthermore, this polymorphism interacts with cue-induced approach behaviour and is a potential biomarker for pharmacological treatment response in AD. In this study, we tested whether the OPRM1 polymorphism is associated with the PIT effect and relapse in AD.

METHODS

Using a PIT task, we examined three independent samples: young healthy subjects (N = 161), detoxified alcohol-dependent patients (N = 186) and age-matched healthy controls (N = 105). We used data from a larger study designed to assess the role of learning mechanisms in the development and maintenance of AD. Subjects were genotyped for the A118G (rs1799971) polymorphism of the OPRM1 gene. Relapse was assessed after three months.

RESULTS

In all three samples, participants with the minor OPRM1 G-Allele (G+ carriers) showed increased expression of the PIT effect in the absence of learning differences. Relapse was not associated with the OPRM1 polymorphism. Instead, G+ carriers displaying increased PIT effects were particularly prone to relapse.

CONCLUSION

These results support a role for the opioid system in incentive salience motivation. Furthermore, they inform a mechanistic model of aberrant salience processing and are in line with the pharmacological potential of opioid receptor targets in the treatment of AD.

Sensory cue reactivity: Sensitization in alcohol use disorder and obesity

Neuroimaging techniques to measure the function of the human brain such as electroencephalography (EEG), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI), are powerful tools for understanding the underlying neural circuitry associated with alcohol use disorder (AUD) and obesity. The sensory (visual, taste and smell) paradigms used in neuroimaging studies represent an ideal platform to investigate the connection between the different neural circuits subserving the reward/executive control systems in these disorders, which may offer a translational mechanism for novel intervention predictions. Thus, the current review provides an integrated summary of the recent neuroimaging studies that have applied cue-reactivity paradigms and neuromodulation strategies to explore underlying alterations in neural circuitry as well in treatment strategies in AUD and obesity. Finally, we discuss literature on mechanisms associated with increased alcohol sensitivity post-bariatric surgery (BS) which offers guidance for future research to use sensory percepts in elucidating the relation of reward signaling in AUD development post-BS.

Immunological Disturbances and Neuroimaging Findings in Major Depressive Disorder (MDD) and Alcohol Use Disorder (AUD) Comorbid Patients

Mood disorders and Major Depressive Disorder, in particular, appear to be some of the most common psychiatric disorders with a high rate of comorbidity most frequently of anxiety or substance abuse disorders (alcohol use disorder). In both cases - MDD and AUD, a number of immunological disturbances are observed, such as chronic mild inflammation response, increased level of cytokines, hypercortisolaemia, which lead to specific changes in brain neurotransmitter functions. Some of the contemporary brain imaging techniques are functional magnetic resonance imaging (fMRI) and magnetic spectroscopy which are most commonly used to assess the brain metabolism and functional connectivity changes such as altered responses to emotional stimuli in MDD or overactivation of ventromedial prefrontal areas during delayed and underactivation of dorsolateral prefrontal regions during impulsive reward decisions in AUD and dysfunction of gamma-aminobutyric acid (GABA) and/or glutamate neurotransmitter systems, low NAA and myo-Inositol in both MDD and AUD.

Does an Over-Connected Visual Cortex Undermine Efforts to Stay Sober After Treatment for Alcohol Use Disorder?

A fine-tuned interplay of highly synchronized activity within and between the brain's communities is a crucial feature of the brain's functional organization. We wanted to investigate in individuals with alcohol use disorder (AUD) the degree to which the interplay of the brain's community-architecture and the extended brain reward system (eBRS) is affected by drinking status (relapse or abstinence). We used Graph Theory Analysis of resting-state fMRI data from treatment seekers at 1 month of abstinence to model the brain's intrinsic community configuration and their follow-up data as abstainers or relapsers 3 months later to quantify the degree of global across-community interaction between the eBRS and the intrinsic communities at both timepoints. After 1 month of abstinence, the ventromedial PFC in particular showed a significantly higher global across-community interaction in the 22 future relapsers when compared to 30 light/non-drinking controls. These differences were no longer present 3 months later when the relapsers had resumed drinking. We found no significant differences between abstainers and controls at either timepoint. Post hoc tests revealed that one eBRS region, the ventromedial PFC, showed a significant global across-community interaction with a community comprising the visual cortex in relapsers at baseline. In contrast, abstainers showed a significant negative association of the ventromedial PFC with the visual cortex. The increased across-community interaction of the ventromedial PFC and the visual cortex in relapsers at timepoint 1 may be an early indicator for treatment failure in a subgroup of AUD patients.

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.

Gambling disorder

Gambling disorder is characterized by a persistent, recurrent pattern of gambling that is associated with substantial distress or impairment. The prevalence of gambling disorder has been estimated at 0.5% of the adult population in the United States, with comparable or slightly higher estimates in other countries. The aetiology of gambling disorder is complex, with implicated genetic and environmental factors. Neurobiological studies have implicated cortico-striato-limbic structures and circuits in the pathophysiology of this disorder. Individuals with gambling disorder often go unrecognized and untreated, including within clinical settings. Gambling disorder frequently co-occurs with other conditions, particularly other psychiatric disorders. Behavioural interventions, particularly cognitive-behavioural therapy but also motivational interviewing and Gamblers Anonymous, are supported in the treatment of gambling disorder. No pharmacological therapy has a formal indication for the treatment of gambling disorder, although placebo-controlled trials suggest that some medications, such as opioid-receptor antagonists, may be helpful. Given the associations with poor quality of life and suicide, improved identification, prevention, policy and treatment efforts are needed to help people with gambling disorder.

Neuroimaging findings from an experimental pharmacology trial of naltrexone in heavy drinkers of East Asian descent

BACKGROUND

Despite known genetic variation across races, studies examining pharmacogenetics of a single nucleotide polymorphism (SNP) of the mu-opioid receptor gene (OPRM1) on clinical response to naltrexone have been conducted in predominantly Caucasian samples. Evidence is mixed for pharmacogenetic OPRM1 and naltrexone effects on neural responses to alcohol cues. The current study tests the pharmacogenetic effects of naltrexone and OPRM1 on neural responses to alcohol taste cues in heavy drinkers of East Asian descent.

METHODS

Participants (N = 41) completed two double-blinded and counterbalanced functional magnetic resonance imaging (fMRI) sessions: one after taking naltrexone (50 mg/day) for four days and one after taking placebo for four days. Following titration, participants completed an fMRI alcohol taste-cues task. Analyses tested effects of naltrexone, OPRM1, and their interaction in whole-brain and region of interest (ROI) analyses of functional activation and functional connectivity in response to alcohol versus water taste cues.

RESULTS

We found no effects of naltrexone orOPRM1 on neural activation in whole-brain and ROI analyses, which included left and right ventral striatum (VS), anterior cingulate cortex (ACC), and orbitofrontal cortex (OFC). Naltrexone increased functional connectivity between left VS and clusters in medial prefrontal cortex, posterior cingulate gyrus, as well as right VS and occipital cortex, compared to placebo.

CONCLUSIONS

Naltrexone treatment enhanced functional connectivity in a key reinforcement-related pathway during alcohol versus water taste cues, corroborating neuroimaging work with other substances. Null medication and pharmacogenetics effects on functional activation add to a mixed naltrexone literature and may underscore the modest size of these effects in East Asians.

Multisensory Environments to Measure Craving During Functional Magnetic Resonance Imaging

There are limited functional magnetic resonance imaging (fMRI) studies that measure alcohol craving with multisensory environments. Researchers are faced with a two-fold challenge: to recreate a naturalistic environment during an MRI scan and to produce paradigms that mimic real-life conditions involved with craving. Craving is a multifaceted psychological construct and techniques such as fMRI provide an alternative way to measure craving and to have a better understanding of its complexity. Most studies to date have implemented visual stimuli to measure craving and only a few studies have investigated gustation and olfaction. Moving forward, there needs to be greater attention on the ways in which we measure craving and the use of multisensory environments during fMRI. By going beyond examining subjective craving responses, and investigating neurobiological responses such as brain activity during fMRI, can potentially lead to better treatments for alcohol use disorder. Further, there needs to be additional consideration on standardizing how we measure craving, which will allow for a more unified approach amongst researchers.

Brain Responses to Anticipation and Consumption of Beer with and without Alcohol

Beer is a popular alcoholic beverage worldwide. Nonalcoholic beer (NA-beer) is increasingly marketed. Brain responses to beer and NA-beer have not been compared. It could be that the flavor of beer constitutes a conditioned stimulus associated with alcohol reward. Therefore, we investigated whether oral exposure to NA-beer with or without alcohol elicits similar brain responses in reward-related areas in a context where regular alcoholic beer is expected. Healthy men (n = 21) who were regular beer drinkers were scanned using functional MRI. Participants were exposed to word cues signaling delivery of a 10-mL sip of chilled beer or carbonated water (control) and subsequent sips of NA-beer with or without alcohol or water (control). Beer alcohol content was not signaled. The beer cue elicited less activation than the control cue in the primary visual cortex, supplementary motor area (reward-related region) and bilateral inferior frontal gyrus/frontal operculum. During tasting, there were no significant differences between the 2 beers. Taste activation after swallowing was significantly greater for alcoholic than for NA-beer in the inferior frontal gyrus/anterior insula and dorsal prefrontal cortex (superior frontal gyrus). This appears to be due to sensory stimulation by ethanol rather than reward processing. In conclusion, we found no differences in acute brain reward upon consumption of NA-beer with and without alcohol, when presented in a context where regular alcoholic beer is expected. This suggests that in regular consumers, beer flavor rather than the presence of alcohol is the main driver of the consumption experience.

Mindfulness buffers the effects of cue-induced craving on alcohol demand in college drinkers

Alcohol consumption among young adult college students represents a significant public health problem. The presence of alcohol-related cues in drinkers' environments can trigger powerful alcohol cravings, which may influence drinking outcomes. Less is known about how this cue-induced craving influences behavioral economic demand for alcohol. In addition, research has suggested that trait mindfulness may be an important buffer of the effects of internal states of craving on drinking decisions. Based on this literature, we hypothesized that cue-induced cravings would be associated with increased alcohol demand, an effect that would be attenuated among drinkers who have higher levels of mindfulness. Young adult college student drinkers (n = 69) completed a laboratory-based cue-induced craving assessment, a self-report assessment of trait mindfulness, and an alcohol purchase task. Findings revealed that cue-induced craving was related to higher alcohol demand. Consistent with the study hypothesis, acceptance, a component of mindfulness, buffered the effects of cue-induced craving on alcohol demand. Results raise the possibility that mindfulness-based interventions may be useful in helping disrupt the link between internal states of craving and drinking decisions in young adult college student drinkers.

Development, Initial Testing and Challenges of an Ecologically Valid Reward Prediction Error FMRI Task for Alcoholism

Aims

To advance translational studies of the role of reward prediction error (PE) in alcohol use disorder, the present study sought to develop and conduct an initial test of an alcohol-specific PE task paradigm using functional magnetic resonance imaging in humans.

Methods

Alcohol dependent or social drinkers received small tastes of their preferred alcohol beverage or control beverage, with preceding visual cues indicating whether alcohol (or water) would be delivered. To assess both positive and negative PE signals, expectancies were systematically violated in both positive (i.e. expecting water and receiving alcohol) and negative (i.e. expecting alcohol and receiving water) directions. Exploratory trial-by-trial analyses were conducted to explore temporal fluctuations of activation within a priori-defined regions of interest that have been implicated in cue reactivity and PE processing.

Results

Across the entire sample of participants, positive PE-related brain activation was found in a large cluster comprised of frontal lobe regions, as well as insular cortex, and motor/sensory cortices. Compared to social drinking subjects, alcohol dependent subjects had greater positive PE-related brain activity in left superior parietal lobule, lateral occipital cortex and postcentral gyrus. Exploratory trial-by-trial analyses indicated differences in activation specific to type of taste, mostly at earlier trials.

Conclusions

This task-development oriented pilot study found that PE signaling may not be detected in expected brain regions when image analyses average across all PE trials of the task. Rather, a trial-by-trial analysis approach may help detect sparse, temporally distinct PE signaling in expected reward processing regions.

Short Summary

This fMRI study of reward prediction error found greater positive prediction error-related activity (i.e. expecting water taste, receiving alcohol taste) in alcohol dependent individuals relative to social drinkers in parietal and occipital cortices. Trial-by-trial analyses may be able to better detect sparse prediction error signaling in expected reward processing regions.

A Critical Review of Methods and Results in the Search for Genetic Contributors to Alcohol Sensitivity

Attributes of alcohol sensitivity are present before alcohol use disorders (AUDs) develop, they predict those adverse alcohol outcomes, are familial in nature, and many are heritable. Whether measured by alcohol challenges or retrospective reports of numbers of drinks required for effects, alcohol sensitivity reflects multiple phenotypes, including low levels of alcohol response and alcohol-related stimulation. Identification of genes that contribute to alcohol sensitivity could help identify individuals carrying risks for AUDs through their alcohol responses for whom early intervention might mitigate their vulnerability. Such genes could also improve understanding of biological underpinnings of AUDs, which could lead to new treatment approaches. However, the existing literature points to a wide range of genetic mechanisms that might contribute to alcohol responses, and few such genetic findings have been widely replicated. This critical review describes the potential impact of the diverse methods used to study sensitivity on the diversity of genetic findings that have been reported, places the genetic variants mentioned in the literature into broader categories rather than isolated results, and offers suggestions regarding how to advance the field by interpreting findings in light of the methods used to select research subjects and to measure alcohol sensitivity. To date, the most promising results have been for GABA, glutamate, opioid, dopamine, serotonin, and cholinergic system genes. The more gene variants that can be identified as contributors to sensitivity the better future gene screening platforms or polygenic scores are likely to be.

The neural correlates of priming emotion and reward systems for conflict processing in alcoholics

Emotional dysregulation in alcoholism (ALC) may result from disturbed inhibitory mechanisms. We therefore tested emotion and alcohol cue reactivity and inhibitory processes using negative priming. To test the neural correlates of cue reactivity and negative priming, 26 ALC and 26 age-matched controls underwent functional MRI performing a Stroop color match-to-sample task. In cue reactivity trials, task-irrelevant emotion and alcohol-related pictures were interspersed between color samples and color words. In negative priming trials, pictures primed the semantic content of an alcohol or emotion Stroop word. Behaviorally, both groups showed response facilitation to picture cue trials and response inhibition to primed trials. For cue reactivity to emotion and alcohol pictures, ALC showed midbrain-limbic activation. By contrast, controls activated frontoparietal executive control regions. Greater midbrain-hippocampal activation in ALC correlated with higher amounts of lifetime alcohol consumption and higher anxiety. With negative priming, ALC exhibited frontal cortical but not midbrain-hippocampal activation, similar to the pattern observed in controls. Higher frontal activation to alcohol-priming correlated with less craving and to emotion-priming with fewer depressive symptoms. The findings suggest that neurofunctional systems in ALC can be primed to deal with upcoming emotion- and alcohol-related conflict and can overcome the prepotent midbrain-limbic cue reactivity response.

The Neurobiological Mechanism of Chemical Aversion (Emetic) Therapy for Alcohol Use Disorder: An fMRI Study

A recent NIH epidemiology study found the lifetime prevalence of alcohol use disorder in the United States to be 29%. Alcohol drinking behavior is strongly "learned" via pleasure center activation/reinforcement. Alcohol craving is a powerful desire to drink alcoholic beverages. Craving was added as one of the defining criteria for alcohol use disorder in DSM5, and craving reduction is becoming an increasingly important treatment goal. In the current study, patients with alcohol use disorder received 10 days of inpatient multi-modal treatments at Schick Shadel Hospital (SSH) of Seattle. The treatments included five chemical aversion conditioning sessions that associated alcohol cues (and alcohol) with nausea and emesis. All patients met DSM4 criteria for alcohol use disorder, were heavy drinkers, and reported craving alcohol pre-treatment. Craving reduction was one of the primary treatment goals. This is the first fMRI study to measure the effects of chemical aversion therapy on alcohol craving-related brain activity. Patients were recruited as subjects for the University of Washington (UW) brain scan study following SSH admission but before treatment onset. Prior to treatment, patients reported craving/desire for alcohol. After treatment (after four SSH chemical aversion treatments, again after five SSH chemical treatments, 30 and 90-days post-discharge), these same patients reported avoidance/aversion to alcohol. Most of the participants (69%) reported being still sober 12 months post-treatment. Consistent with a craving reduction mechanism of how chemical aversion therapy facilitates sobriety, results of the UW fMRI brain scans showed significant pre- to post-treatment reductions in craving-related brain activity in the occipital cortex. Additional fMRI brain scan studies are needed to further explore the neurobiological mechanism of chemical aversion therapy treatment for alcohol use disorder, and other substance use disorders for which chemical aversion therapy is used (e.g., opioid dependence and cocaine dependence). Substance use disorders are estimated to affect well over one billion people worldwide.

A cis-eQTL in OPRM1 is Associated with Subjective Response to Alcohol and Alcohol Use

BACKGROUND

A functional polymorphism within the μ-opioid receptor (OPRM1) gene, rs1799971 (A118G), previously has been associated with measures of alcohol use and sensitivity to its effects, but findings have been inconclusive. A recent study suggested that a second nearby variant within OPRM1, rs3778150, is robustly associated with heroin dependence and fully explained a smaller observed association with rs1799971. Given evidence that the rs3778150-C allele is associated with decreased OPRM1 expression levels in the human brain, the current study sought to test the hypothesis that rs3778150 represents a causal variant within OPRM1 that increases risk for a variety of alcohol use phenotypes.

METHODS

Participants with genotype and phenotype data from a larger experimental study (N = 152) were assessed on measures of subjective response to alcohol and alcohol use. Measures included (i) the Self-Rating of the Effects of Alcohol and the Alcohol Sensitivity Questionnaire, (ii) the Biphasic Alcohol Effects Scale (BAES) and ratings of subjective intoxication, and (iii) average number of drinks per week in the past month.

RESULTS

Compared to rs3778150-T homozygous individuals, carriers of the rs3778150-C allele exhibited significantly lower retrospective self-report levels of alcohol sensitivity. Carriers of the rs3778150-C allele also exhibited lower levels of BAES alcohol-related stimulation during an alcohol challenge and reported higher levels of drinking in the last 30 days. With the exception of lower levels of BAES alcohol-related sedation, the rs1799971 variant did not show consistent significant association with any of the alcohol phenotypes in the presence of rs3778150.

CONCLUSIONS

Results suggest that rs3778150 may be causally related to alcohol use phenotypes, and could potentially account for previously observed associations of rs1799971 with substance use phenotypes. Future studies may investigate potential causal relations among genetic variants in OPRM1, subjective response to alcohol, and drinking phenotypes to further delineate the effects of rs3778150.

Neuroscience of drug craving for addiction medicine: From circuits to therapies

Drug craving is a dynamic neurocognitive emotional-motivational response to a wide range of cues, from internal to external environments and from drug-related to stressful or affective events. The subjective feeling of craving, as an appetitive or compulsive state, could be considered a part of this multidimensional process, with modules in different levels of consciousness and embodiment. The neural correspondence of this dynamic and complex phenomenon may be productively investigated in relation to regional, small-scale networks, large-scale networks, and brain states. Within cognitive neuroscience, this approach has provided a long list of neural and cognitive targets for craving modulations with different cognitive, electrical, or pharmacological interventions. There are new opportunities to integrate different approaches for carving management from environmental, behavioral, psychosocial, cognitive, and neural perspectives. By using cognitive neuroscience models that treat drug craving as a dynamic and multidimensional process, these approaches may yield more effective interventions for addiction medicine.