Effects of Varenicline on Neural Correlates of Alcohol Salience in Heavy Drinkers

Novel paradigms for the gut-brain axis during alcohol withdrawal, withdrawal-associated depression, and craving in patients with alcohol use disorder

Introduction

Patients with alcohol use disorder (AUD) exhibit symptoms such as alcohol withdrawal, depression, and cravings. The gut-immune response may play a significant role in manifesting these specific symptoms associated with AUD. This study examined the role of gut dysfunction, proinflammatory cytokines, and hormones in characterizing AUD symptoms.

Methods

Forty-eight AUD patients [men (n = 34) and women (n = 14)] aged 23-63 years were grouped using the Clinical Institute Withdrawal Assessment of Alcohol Scale (CIWA) as clinically significant (CS-CIWA [score > 10] [n = 22]) and a clinically not-significant group (NCS-CIWA [score ≤ 10] [n = 26]). Clinical data (CIWA, 90-day timeline followback [TLFB90], and lifetime drinking history [LTDH]) and blood samples (for testing proinflammatory cytokines, hormones, and markers of intestinal permeability) were analyzed. A subset of 16 AUD patients was assessed upon admission for their craving tendencies related to drug-seeking behavior using the Penn-Alcohol Craving Score (PACS).

Results

CS-CIWA group patients exhibited unique and significantly higher levels of adiponectin and interleukin (IL)-6 compared to NCS-CIWA. In the CS group, there were significant and high effects of association for the withdrawal score with gut-immune markers (lipopolysaccharide [LPS], adiponectin, IL-6, and IL-8) and for withdrawal-associated depression with gut-immune markers (scored using MADRS with LPS, soluble cells of differentiation type 14 [sCD14], IL-6, and IL-8). Craving (assessed by PACS, the Penn-Alcohol Craving Scale) was significantly characterized by what could be described as gut dysregulation (LBP [lipopolysaccharide binding protein] and leptin) and candidate proinflammatory (IL-1β and TNF-α) markers. Such a pathway model describes the heavy drinking phenotype, HDD90 (heavy drinking days past 90 days), with even higher effects (R2 = 0.955, p = 0.006) in the AUD patients, who had higher ratings for cravings (PACS > 5).

Discussion

The interaction of gut dysfunction cytokines involved in both inflammation and mediating activity constitutes a novel pathophysiological gut-brain axis for withdrawal symptoms and withdrawal-associated depression and craving symptoms in AUD. AUD patients with reported cravings show a significant characterization of the gut-brain axis response to heavy drinking.

Trial registration

ClinicalTrials.gov, identifier: NCT# 00106106.

Free-access intravenous alcohol self-administration in social drinkers and individuals with alcohol use disorder: Evaluation of relationships with phosphatidylethanol and self-reported alcohol consumption

BACKGROUND

The free-access (FA) intravenous alcohol self-administration (IV-ASA) paradigm is an experimental approach that can identify modulators of alcohol consumption in humans. Moreover, the outcome measures of IV-ASA paradigms are associated with self-reported alcohol intake using the timeline follow-back method (TLFB). To evaluate how FA IV-ASA reflects drinking in real life, we examined the relationship between an objective marker of recent alcohol intake, phosphatidylethanol in blood (B-PEth), and TLFB and measures obtained during IV-ASA in individuals with alcohol use disorder (AUD) and social drinkers (SD). We also explored the associations between these measures and gut-brain peptides involved in AUD pathophysiology.

METHODS

Thirty-eight participants completed a laboratory session in which they self-administered alcohol intravenously. The safety limit was 200 mg%, and main outcomes were mean and peak breath alcohol concentrations (BrAC). Blood samples were drawn prior to IV-ASA and subjective alcohol effects were rated during the experiment.

RESULTS

The study sample comprised 24 SD and 14 participants with DSM-5 mild AUD. Although BrACs were not associated with B-PEth or TLFB in the full sample or AUD subgroup, there was an association with TLFB in SD. In both subgroups, BrACs were associated with alcohol craving but with differential timing. Total ghrelin levels were higher in AUD participants than in SD.

CONCLUSIONS

No associations between B-PEth levels and achieved BrACs were observed in the mild AUD group, the SD group, or the full sample. The ability for FA IV-ASA to reflect recent drinking was confirmed only for TLFB in SD, whereas there were no associations within the smaller subsample of participants with mild AUD or in the full sample. Further studies that include a larger AUD sample are warranted. The association of BrACs with craving for alcohol suggests that the IV-ASA method may be useful for assessing interventions that target craving. This could be explored by using the FA IV-ASA model to evaluate the effects on craving of approved pharmacotherapies for AUD.

Diagnostic Prospectives with Tau Protein and Imaging Techniques to Detect Development of Chronic Traumatic Encephalopathy

Brain damage sustained from repeated blows in boxing, wrestling, and other combat sports has serious physical and mental health consequences. The degenerative brain disease, chronic traumatic encephalopathy (CTE), presents clinically with memory loss, aggression, difficulty in rational thinking and other cognitive problems. This spectrum, which mimics Alzheimer's disease, is diagnosed post-mortem through a brain biopsy in many professional athletes. However, little is known about the process of development and how to identify vulnerable individuals who may be on course for developing CTE. Boxing is a sport that has a severe toll on athletes' health, primarily on their brain health and function. This review addresses the concerns of brain injury, describes the pathologies that manifest in multiple scales, e.g., molecular and cognitive, and also proposes possible diagnostic and prognostic markers to characterize the early onset of CTE along with the aim to identify a starting point for future precautions and interventions.

Alcohol use disorder in community management of chronic liver diseases

Rising rates of alcohol use disorder (AUD) combined with increases in alcohol-related liver disease (ALD) and other liver disease have resulted in the need to develop alcohol management strategies at all levels of patient care. For those with pre-existing liver disease, whether ALD or others, attention to alcohol use treatment and abstinence becomes critical to avoiding worsening liver-related consequences. Modalities to help patients reduce or stop alcohol include screening/brief intervention/referral to treatment, various therapeutic modalities including cognitive behavioral therapy, motivational enhancement therapy and 12-step facilitation, and alcohol relapse prevention medications. Harm reduction approaches versus total abstinence may be considered, but for those with existing ALD, particularly advanced ALD (cirrhosis or acute alcoholic hepatitis), total abstinence from alcohol is the recommendation, given clear data that ongoing alcohol use worsens mortality and liver-related morbidity. For certain populations, alcohol cessation is even more critically important. For those with hepatitis C or NAFLD, alcohol use accelerates negative liver-related outcomes. In women, alcohol use accelerates liver damage and results in worsened liver-related mortality. Efforts to integrate AUD and liver disease care are urgently needed and can occur at several levels, with establishment of multidisciplinary ALD clinics for fully integrated co-management as an important goal.

Combined varenicline and naltrexone attenuates alcohol cue-elicited activation in heavy drinking smokers

BACKGROUND

There is a strong bidirectional relationship between the use of alcohol and cigarettes which results in various challenges for treating those who co-use both substances. While varenicline and naltrexone each have FDA-approval for nicotine and alcohol use disorder, respectively, there is evidence that their clinical benefit may extend across the two disorders. Critically, the effect of combined varenicline and naltrexone on neural reactivity to alcohol cues among heavy drinking smokers has not yet been studied. Probing the effect of the combination therapy on alcohol cue-reactivity may give insight to the mechanisms underlying its efficacy.

METHODS

Forty-seven heavy drinking smokers enrolled in two medication studies were randomized to receive varenicline alone (n = 11), varenicline plus naltrexone (n = 11), or placebo (n = 25). Participants completed an fMRI alcohol cue-reactivity task and rated their in-scanner alcohol craving. Whole-brain analyses examined the effect of medication on alcohol cue-elicited neural response.

RESULTS

Varenicline plus naltrexone attenuated alcohol cue-elicited activation in mesolimbic regions relative to varenicline alone and to placebo (Z > 2.3, p < 0.05). The combination varenicline and naltrexone group also endorsed lower in-scanner alcohol craving relative to varenicline alone group (p = 0.04).

CONCLUSIONS

These findings provide evidence for the benefit of combined therapy of varenicline and naltrexone over varenicline alone for the attenuation of alcohol cue-elicited neural activation. This study provides a preliminary proof-of-mechanism for this combination pharmacotherapy and suggests that naltrexone may be driving the reductions in cue-elicited alcohol craving in the brain. Further clinical studies using the combined therapy to treat heavy drinking smokers are warranted.

A Critical Review of Alcohol Administration Guidelines in Laboratory Medication Screening Research: Is It Time to Include Treatment Seekers?

Human laboratory studies play an important role in alcohol use disorder (AUD) medication development. Medications that are found to be safe and effective during human laboratory screening will then move to more expensive clinical trials in patient populations. Given the gatekeeping role of human laboratory studies in the medication development pipeline, it is critical that these studies accurately forecast how pharmacotherapies will perform under true-to-life clinical conditions. On the other hand, the design of these studies also must adhere to ethical guidelines: certain aspects of clinical reality cannot be incorporated into screening studies because doing so might place the participant at risk for harm or breach other ethical guidelines. Conventions exist that guide the resolution of these conflicting ideals. This article considers the practice of recruiting non-treatment-seeking heavy drinkers to participate in laboratory screening studies. By convention, volunteers are excluded from laboratory screening studies that involve alcohol administration if they are deemed "treatment seeking," meaning that they recently stopped drinking or are motivated to do so. Although this common practice may reduce risk to participants, findings may not accurately predict medication effects on treatment seekers. Indeed, there is empirical evidence that treatment seekers differ from nontreatment seekers in their responses to medications (Neuropsychopharmacology 2017a; 42: 1776; Am J Drug Alcohol Abuse 2017b; 43: 703; J Psychiatr Res 2006; 40: 383). Here, we argue for the importance of recruiting treatment seekers for this research due to their qualitative difference from nontreatment seekers. We argue that these individuals should be the default population in human laboratory medication screening studies. We conclude by discussing 2 case examples of medication experiments led by our research groups that involved administering medications to treatment seekers.

Interaction of Heavy Drinking Patterns and Depression Severity Predicts Efficacy of Quetiapine Fumarate XR in Lowering Alcohol Intake in Alcohol Use Disorder Patients

Background:

Shared etiological pathways of dopamine and serotonin neurotransmission play a central role in heavy alcohol intake and exacerbation in the symptoms of depression.

We investigated the treatment efficacy of Quetiapine fumarate extended release (XR) in lowering alcohol intake in alcohol use disorder (AUD) patients indicated by the shared alleviation of depression ratings and patterns of heavy drinking.

Methods:

Hundred and eight male and female heavy drinking AUD patients in the age range of 18 to 64 years. participated in a randomized clinical trial (RCT) to receive 12 weeks of quetiapine XR or placebo (N = 115). Participants were sub-grouped by the severity grading of depression using Montgomery-Asberg Depression Rating Scale (MADRS) (clinically relevant ⩾8 [CR], clinically non-relevant ⩽7 [CNR]) at baseline in both the groups. Drinking history and depression ratings were assessed at the patients’ visits.

Results:

Heavy drinking days (HDD) and total drinks (TD) were significantly fewer in CR patients at the treatment end. A true positive response in AUROC analysis supported the lowering of TD in CR patients. The number of drinking days (NDD) and average drinks per drinking day (AvgD) were lower in the CNR patients at treatment-end. Significant associations with increasing effect sizes were observed for all the heavy drinking measures (HDD, TD, NDD, and AvgD) and MADRS scores by the end of the treatment course.

Conclusions:

Baseline elevated depressive symptoms could likely predict the course of heavy alcohol drinking during the treatment, and efficacy outcome of a treatment. AUD patients with baseline clinically significant depression had a progressive lowering in heavy drinking markers significantly corresponding to the lowering of depression symptoms by the end of treatment with Quetiapine fumarate XR.

ClinicalTrials.gov: NCT#0049862 (https://clinicaltrials.gov/ct2/show/NCT00498628?term=litten&draw=2&rank=3)

Ibudilast for alcohol use disorder: study protocol for a phase II randomized clinical trial

BACKGROUND

Alcohol use disorder (AUD) is a chronic and relapsing condition for which current pharmacological treatments are only modestly effective. The development of efficacious medications for AUD remains a high research priority with recent emphasis on identifying novel molecular targets for AUD treatment and to efficiently screen new compounds aimed at those targets. Ibudilast, a phosphodiesterase inhibitor, has been advanced as a novel addiction pharmacotherapy that targets neurotrophin signaling and neuroimmune function.

METHODS

This study will conduct a 12-week, double-blind, placebo controlled randomized clinical trial of ibudilast (50 mg BID) for AUD treatment. We will randomize 132 treatment-seeking men and women with current AUD. We will collect a number of alcohol consumption outcomes. Primary among these is percent heavy drinking days (PHDD); secondary drinking outcomes include drinks per day, drinks per drinking day, percent days abstinent, percent subjects with no heavy drinking days, and percent subjects abstinent, as well as measures of alcohol craving and negative mood. Additionally, participants will have the option to opt-in to a neuroimaging session in which we examine the effects of ibudilast on neural activation to psychosocial stress and alcohol cues. Finally, we will also collect plasma levels of proinflammatory markers, as well as subjective and biological (salivary cortisol) markers of stress response.

DISCUSSION

This study will further develop ibudilast, a safe and promising novel compound with strong preclinical and clinical safety data for AUD, and will probe biological mechanisms underlying the effects of Ibudilast on stress, neuroinflammation, and alcohol cue-reactivity and craving. If ibudilast proves superior to placebo in this study, it will set the stage for a confirmatory multi-site trial leading to FDA approval of a novel AUD treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03594435 "Ibudilast for the Treatment of Alcohol Use Disorder". Registered on 20 July 2018.

The Human Laboratory and Drug Development in Alcohol Use Disorder: Recent Updates

Despite a number of approved medications for alcohol use disorder (AUD), this chronic relapsing disease still produces a considerable global burden, with both health-related and financial consequences. While clinical trials are a critical step in drug development, human laboratory studies provide the field with means of screening pharmacotherapy for more nuanced aspects of AUD. Specifically, studies employing alcohol administration techniques (e.g., alcohol challenge and self-administration) are able to investigate potential drugs with respect to their ability to alter various responses to alcohol administration or alter alcohol consumption in laboratory settings. This chapter reviews methodological designs and provides updates from alcohol administration studies used to screen for potential AUD pharmacotherapy over the past decade. These recent studies have supported the efficacy of approved drugs, identified some promising novel drugs, and investigated other drugs that appear ineffective in AUD treatment. Yet, few drugs are explored using the different variants of alcohol administration methods, and using the different methods has provided inconsistent results for the same drug. Future research would aid advancement in the field by testing medication with various methodologies and refining recently developed techniques.

High-risk social drinkers and heavy drinkers display similar rates of alcohol consumption

Alcohol consumption is often assessed over weeks to months, but few attempts have been made to characterize alcohol consumption rates at the level of an individual drinking session. Here, we aimed to compare the rate of alcohol consumption in social drinkers at high risk for alcohol use disorder (AUD) and heavy drinkers. One hundred and sixty social drinkers and 48 heavy drinkers participated in an alcohol self-administration study. Social drinkers were classified as low risk or high risk for AUD based on sex, impulsivity, and family history of alcoholism. Participants received a priming dose of intravenous alcohol to assess alcohol-induced craving and completed a 125-minute intravenous alcohol self-administration session to assess rate of achieving a binge-level exposure (blood alcohol concentration greater than or equal to 80 mg%). There were no differences between rates of binging in high-risk and heavy drinkers (hazard ratio = 0.87; 95% CI, 0.48-1.56). Heavy drinkers reported higher levels of craving than high-risk and low-risk drinkers at baseline. However, following a priming dose of alcohol, there were no longer differences in craving between high-risk and heavy drinkers. These results indicate that high-risk social drinkers demonstrate binging behavior that is similar to heavy drinkers, which may be driven by alcohol-induced craving. Prospective studies are needed to elucidate whether these patterns of craving and consumption in high-risk social drinkers are predictive of future AUD.

Efficacy and acceptability of varenicline for alcoholism: A systematic review and meta-analysis of randomized-controlled trials

BACKGROUND

Current pharmacological treatment for alcoholism remains unsatisfactory. While there have been several clinical trials investigating the efficacy and safety of the therapeutic use of varenicline in alcoholism, no definitive review of this topic has been carried out. This systematic review aimed to determine the efficacy and acceptability of the use of varenicline in treating alcoholism.

METHODS

This systematic review included double-blinded, randomized, placebo-controlled trials reporting heavy drinking days, amount of alcohol consumption, overall dropouts, or dropouts due to adverse events. We searched PubMed, Scopus, Web of Science, ClinicalTrials.gov, and the Cochrane Library in January 2019. We independently selected the trials and assessed the quality of included studies. We calculated standardized mean differences on heavy drinking days and the amount of alcohol consumption. We calculated the relative risks for dropout rate. All data were pooled using random-effects models.

RESULT

This systematic review included nine double-blind, randomized, placebo-controlled trials (N = 585). The study duration ranged from 4 to 13 weeks. Varenicline therapy was not superior to placebo in decreasing heavy drinking days but significantly superior to placebo in decreasing alcohol consumption. There were no statistically significant differences between groups on dropout rates due to any reason or due to adverse events.

CONCLUSION

Varenicline therapy is effective in decreasing alcohol consumption over a period of time. It may be an option for decreasing heavy drinking days in patients with alcoholism. It is a well-accepted medication for alcoholism. More studies are needed to determine if varenicline is effective in decreasing heavy drinking.

Exacerbation of Hangover Symptomology Significantly Corresponds with Heavy and Chronic Alcohol Drinking: A Pilot Study

Alcohol hangover is a combination of mental, sympathetic, and physical symptoms experienced the day after a single period of heavy drinking, starting when blood alcohol concentration approaches zero. How individual measures/domains of hangover symptomology might differ with moderate to heavy alcohol consumption and how these symptoms correlate with the drinking markers is unclear. We investigated the amount/patterns of drinking and hangover symptomology by the categories of alcohol drinking. We studied males and females in three groups: 12 heavy drinkers (HD; >15 drinks/week, 34–63 years old (y.o.)); 17 moderate drinkers (MD; 5–14 drinks/week, 21–30 y.o.); and 12 healthy controls (social/light drinkers, SD; <5 drinks/week, 25–54 y.o.). Demographics, drinking measures (Timeline followback past 90 days (TLFB90), Alcohol Use Disorders Identification Test (AUDIT)), and alcohol hangover scale (AHS) were analyzed. Average drinks/day was 5.1-times greater in HD compared to MD. Average AHS score showed moderate incapacity, and individual measures and domains of the AHS were significantly elevated in HD compared to MD. Symptoms of three domains of the AHS (mental, gastrointestinal, and sympathetic) showed domain-specific significant increase in HD. A domain-specific relation was present between AUDIT and specific measures of AHS scores in HD, specifically with the dependence symptoms. Exacerbation in hangover symptomology could be a marker of more severe alcohol use disorder.

The Use of Functional Magnetic Resonance Imaging to Test Pharmacotherapies for Alcohol Use Disorder: A Systematic Review

Alcohol use disorder (AUD) is a chronic relapsing condition that represents a significant public health concern. Pharmacological treatment development for AUD is a top research priority, and many studies are being conducted to evaluate potential AUD treatments. Understanding the brain circuitry impacted by addiction is crucial for the development of efficacious pharmacological interventions. These neuroadaptations can be probed noninvasively using functional magnetic resonance neuroimaging (fMRI). fMRI may be an effective tool to identify biomarkers for AUD pharmacotherapies, evaluating changes associated with pharmacological treatment. Thus, the present qualitative review of the literature focuses on the role of fMRI as a tool for medication development for AUD. The aim of this review was to assemble research across a range of fMRI paradigms to study the effectiveness of pharmacological treatments of adult AUD. First, we present a qualitative review of fMRI AUD pharmacotherapy studies, differentiating studies based on their dosing regimen. Second, we provide recommendations for the field to improve the use of fMRI as a biomarker for AUD pharmacotherapy.

Exogenous ghrelin administration increases alcohol self-administration and modulates brain functional activity in heavy-drinking alcohol-dependent individuals

Preclinical evidence suggests that ghrelin, a peptide synthesized by endocrine cells of the stomach and a key component of the gut-brain axis, is involved in alcohol seeking as it modulates both central reward and stress pathways. However, whether and how ghrelin administration may impact alcohol intake in humans is not clear. For, we believe, the first time, this was investigated in the present randomized, crossover, double-blind, placebo-controlled, human laboratory study. Participants were non-treatment-seeking alcohol-dependent heavy-drinking individuals. A 10-min loading dose of intravenous ghrelin/placebo (3 mcg kg^-1) followed by a continuous ghrelin/placebo infusion (16.9 ng/kg/min) was administered. During a progressive-ratio alcohol self-administration experiment, participants could press a button to receive intravenous alcohol using the Computerized Alcohol Infusion System. In another experiment, brain functional magnetic resonance imaging was conducted while participants performed a task to gain points for alcohol, food or no reward. Results showed that intravenous ghrelin, compared to placebo, significantly increased the number of alcohol infusions self-administered (percent change: 24.97±10.65, P=0.04, Cohen's d=0.74). Participants were also significantly faster to initiate alcohol self-administration when they received ghrelin, compared to placebo (P=0.03). The relationships between breath alcohol concentration and subjective effects of alcohol were also moderated by ghrelin administration. Neuroimaging data showed that ghrelin increased the alcohol-related signal in the amygdala (P=0.01) and modulated the food-related signal in the medial orbitofrontal cortex (P=0.01) and nucleus accumbens (P=0.08). These data indicate that ghrelin signaling affects alcohol seeking in humans and should be further investigated as a promising target for developing novel medications for alcohol use disorder.

Neural Correlates of Compulsive Alcohol Seeking in Heavy Drinkers

BACKGROUND

Compulsive alcohol use, the tendency to continue alcohol seeking and taking despite negative consequences, is a hallmark of alcohol use disorder. Preclinical rodent studies have suggested a role for the medial prefrontal cortex, anterior insula, and nucleus accumbens in compulsive alcohol seeking. It is presently unknown whether these findings translate to humans. We used a novel functional magnetic resonance imaging paradigm and tested the hypothesis that heavy drinkers would compulsively seek alcohol despite the risk of an aversive consequence, and that this behavior would be associated with the activity of frontostriatal circuitry.

METHODS

Non-treatment-seeking heavy and light drinkers (n = 21 per group) completed a functional magnetic resonance imaging paradigm in which they could earn alcohol or food points at various threat levels (i.e., various probabilities of incurring an aversive consequence). Brain function was evaluated when individuals had the opportunity to earn reward points at the risk of an aversive consequence, an electric shock on the wrist.

RESULTS

Compared with light drinkers, heavy drinkers attempted to earn more aversion-paired alcohol points. Frontostriatal circuitry, including the medial prefrontal cortex, anterior insula, and striatum, was more active in this group when viewing threat-predictive alcohol cues. Heavy drinkers had increased connectivity between the anterior insula and the nucleus accumbens. Greater connectivity was associated with more attempts to earn aversion-paired alcohol points and self-reported compulsive alcohol use scores.

CONCLUSIONS

Higher activation of frontostriatal circuitry in heavy drinkers may contribute to compulsive alcohol seeking. Treatments that disrupt this circuitry may result in a decrease in compulsive alcohol use.

Advances in Pharmacotherapy Development: Human Clinical Studies

For more than 25 years, researchers have made advances in developing medications to treat alcohol use disorder (AUD), highlighted by the US Food and Drug Administration's (FDA's) approval of disulfiram, naltrexone (oral and long-acting), and acamprosate. These medications are also approved in Europe, where the European Medicines Agency (EMA) recently added a fourth medication, nalmefene, for AUD. Despite these advances, today's medications have a small effect size, showing efficacy for only a limited number of individuals with AUD. However, a host of new medications, which act on variety of pharmacologic targets, are in the pipeline and have been evaluated in numerous human studies. This article reviews the efficacy and safety of medications currently being tested in human trials and looks at ongoing efforts to identify candidate compounds in human studies. As mentioned in the National Institute on Alcohol Abuse and Alcoholism's Strategic Plan 2017-2021 ( https://www.niaaa.nih.gov/sites/default/files/StrategicPlan_NIAAA_optimized_2017-2020.pdf ), medications development remains a high priority. By developing more effective and safe medications, and identifying those patients who will benefit the most from these treatments, we can provide clinicians with the tools they need to treat this devastating disorder, providing relief for patients and their families and markedly improving public health and safety.

Vulnerability for Alcohol Use Disorder and Rate of Alcohol Consumption

OBJECTIVE

Although several risk factors have been identified for alcohol use disorder, many individuals with these factors do not go on to develop the disorder. Identifying early phenotypic differences between vulnerable individuals and healthy control subjects could help identify those at higher risk. Binge drinking, defined as reaching a blood alcohol level of 80 mg%, carries a risk of negative legal and health outcomes and may be an early marker of vulnerability. Using a carefully controlled experimental paradigm, the authors tested the hypothesis that risk factors for alcohol use disorder, including family history of alcoholism, male sex, impulsivity, and low level of response to alcohol, would predict rate of binging during an individual alcohol consumption session.

METHOD

This cross-sectional study included 159 young social drinkers who completed a laboratory session in which they self-administered alcohol intravenously. Cox proportional hazards models were used to determine whether risk factors for alcohol use disorder were associated with the rate of achieving a binge-level exposure.

RESULTS

A greater percentage of relatives with alcoholism (hazard ratio: 1.04, 95% CI=1.02-1.07), male sex (hazard ratio: 1.74, 95% CI=1.03-2.93), and higher impulsivity (hazard ratio: 1.17, 95% CI=1.00 to 1.37) were associated with a higher rate of binging throughout the session. Participants with all three risk factors had the highest rate of binging throughout the session compared with the lowest risk group (hazard ratio: 5.27, 95% CI=1.81-15.30).

CONCLUSIONS

Binge drinking may be an early indicator of vulnerability to alcohol use disorder and should be carefully assessed as part of a thorough clinical evaluation.

The Effect of Varenicline on the Neural Processing of Fearful Faces and the Subjective Effects of Alcohol in Heavy Drinkers

BACKGROUND

Pharmacotherapies for alcohol use disorder have been shown to reduce hazardous drinking and improve overall health. The effect sizes for the effectiveness of these medications, however, are small, underscoring the need to expand the range of therapeutics and develop personalized treatment approaches. Recent studies have suggested that varenicline, an α4β2-nicotinic partial agonist widely used for smoking cessation, can help alcoholics reduce drinking, but the neurocognitive underpinnings of its effectiveness remain largely unexplored.

METHODS

In this double-blind study, 32 heavy drinkers were randomized to receive varenicline (2 mg/d) or placebo. After 2 weeks of dosing, participants underwent functional MRI scans, during which they viewed images of faces with either neutral or fearful expressions at baseline and following an intravenous alcohol infusion to a target breath alcohol concentration of 80 mg%. Blood oxygen level-dependent (BOLD) response was analyzed with Analysis of Functional Neuroimaging software. Linear mixed-effects models were used to examine the effects of facial expression (fearful vs. neutral) and medication (placebo vs. varenicline) on BOLD response. The effect of medication on measures of subjective response to alcohol was also examined.

RESULTS

Results indicated a significant facial expression-by-medication interaction in the left amygdala. The groups showed equivalent activation to neutral faces, but, whereas the placebo group showed increased activation to fearful faces, the varenicline group showed no change in activation. Amygdala activation to fearful faces correlated with number of drinks in the previous 90 days and Obsessive Compulsive Drinking Scale scores. There was no effect of varenicline on subjective response to alcohol.

CONCLUSIONS

Our results indicate that varenicline may disrupt amygdala response to fearful faces in heavy drinkers. Further, amygdala activation correlated with alcohol consumption, suggesting that the effects of varenicline may be related to aspects of drinking behavior. These results suggest that amygdala response to fearful faces may be developed as a biomarker of the effectiveness of medications being developed for the treatment of alcohol use disorder.

Current insights into the mechanisms and development of treatments for heavy drinking cigarette smokers

There is a strong association between cigarette smoking and alcohol use at the epidemiological, behavioral, and molecular levels, and this co-use creates substantial impediments to smoking cessation among smokers who are also heavy drinkers. Compared with individuals who only smoke, those who both drink and smoke heavily experience more severe health consequences and have greater difficulty in quitting smoking. During smoking abstinence, greater alcohol use is associated with decreased odds of smoking cessation, and smokers are substantially more likely to experience a smoking lapse during drinking episodes. As heavy drinking smokers are less responsive to the currently available pharmacological treatments, this subgroup of high-risk substance users possesses a unique clinical profile and treatment needs. Thus, treatment development for heavy drinking smokers represents a significant and understudied research area within the field of smoking cessation. This review will briefly describe findings from epidemiological, behavioral, and molecular studies illustrating alcohol and tobacco co-use and identify how the behavioral and neurobiological mechanisms underlying the interaction of alcohol and nicotine may inform the development of targeted treatments for this unique population of smokers.