Brain Glutamate, GABA, and Glutamine Levels and Associations with Recent Drinking in Treatment-Naïve Individuals with Alcohol Use Disorder Versus Light Drinkers

BACKGROUND

Proton magnetic resonance spectroscopy (¹ H-MRS) studies have demonstrated abnormal levels of a variety of neurometabolites in inpatients/outpatients with alcohol use disorder (AUD) following acute alcohol withdrawal relative to healthy controls. In contrast, few studies have compared neurometabolite levels between less severe, treatment-naïve AUD individuals and light drinkers (LD) or related them to recent alcohol consumption. The present study compared neurometabolite levels between treatment-naïve AUD and LD individuals.

METHODS

Twenty treatment-naïve individuals with AUD and 20 demographically matched LD completed an ¹ H-MRS scan, approximately 2.5 days following their last reported drink. ¹ H-MRS data were acquired in dorsal anterior cingulate (dACC) using a 2-dimensional J-resolved point-resolved spectroscopy sequence. dACC neurometabolite levels, with a focus on glutamate, glutamine, and GABA, were compared between AUD and LD participants. The associations between metabolite levels and recent drinking were explored.

RESULTS

AUD participants had significantly lower concentrations of GABA (Cohen's d = 0.79, p = 0.017) and glutamine (Cohen's d = 1.12, p = 0.005), but not glutamate (Cohen's d = 0.05, p = 0.893), relative to LD. As previously reported, AUD participants' glutamate and N-acetylaspartate concentrations were inversely associated with their number of heavy drinking days. In contrast, neither number of drinking (mean p = 0.56) nor heavy drinking (mean p = 0.47) days were associated with metabolite concentrations in LD.

CONCLUSIONS

The present study demonstrated significantly lower levels of prefrontal γ-aminobutyric acid and glutamine in treatment-naïve individuals with AUD relative to LD. Whether these findings reflect the neurotoxic consequence and/or neuroadaptive response of alcohol consumption versus a predrinking trait, and therefore a more durable neurochemical disturbance, awaits elucidation from longitudinal studies.

Drinking Risk Level Reductions Associated with Improvements in Physical Health and Quality of Life Among Individuals with Alcohol Use Disorder

BACKGROUND

Abstinence and no heavy drinking days are currently the only Food and Drug Administration-approved end points in clinical trials for alcohol use disorder (AUD). Many individuals who fail to meet these criteria may substantially reduce their drinking during treatment, and most individuals with AUD prefer drinking reduction goals. One- and two-level reductions in World Health Organization (WHO) drinking risk levels have been proposed as alternative end points that reflect reduced drinking and are associated with reductions in drinking consequences, improvements in mental health, and reduced risk of developing alcohol dependence. The current study examined the association between WHO drinking risk level reductions and improvements in physical health and quality of life in a sample of individuals with alcohol dependence.

METHODS

Secondary data analysis of individuals with alcohol dependence (n = 1,142) enrolled in the longitudinal, prospective COMBINE study, a multi site randomized placebo-controlled clinical trial, examining the association between reductions in WHO drinking risk levels and change in blood pressure, liver enzyme levels, and self-reported quality of life following treatment for alcohol dependence.

RESULTS

One- and two-level reductions in WHO drinking risk level during treatment were associated with significant reductions in systolic blood pressure (p < 0.001), improvements in liver enzyme levels (all p < 0.01), and significantly better quality of life (p < 0.001).

CONCLUSIONS

One- and two-level reductions in WHO drinking risk levels predicted significant improvements in markers of physical health and quality of life, suggesting that the WHO drinking risk level reduction could be a meaningful surrogate marker of improvements in how a person "feels and functions" following treatment for alcohol dependence. The WHO drinking risk levels could be useful in medical practice for identifying drinking reduction targets that correspond with clinically significant improvements in health and quality of life.

Identifying chronic heavy alcohol use in emergency general surgery patients: a pilot study

Background

Chronic heavy alcohol (CHA) use has been associated with perioperative complications. Emergency general surgery (EGS) patients are not routinely screened for CHA. If screened, it is usually for hazardous use of alcohol, using a survey such as the Alcohol Use Disorders Identification Test (AUDIT). This study screened EGS patients for CHA use using serum carbohydrate-deficient transferrin (%dCDT) level, a biomarker that has been validated as an indicator for CHA use, as well as the AUDIT. The purpose of this study was to determine the percent of EGS patients with CHA (as indicated by elevated %dCDT), and the relationship between %dCDT and AUDIT. Secondary aims included comparing the characteristics of EGS patients with and without CHA use, and evaluating the association of CHA use with negative clinical outcomes.

Methods

EGS patients aged 21 and older admitted to the general surgery inpatient service of a tertiary hospital from July 2014 to June 2016 were invited to participate in this study. %dCDT levels above 1.7% were considered positive for CHA use, as were AUDIT scores ≥8.

Results

195 EGS patients were screened for inclusion and 91 (46.7%) agreed to participate. 14 (15.4%) were positive for hazardous alcohol use on AUDIT and 5 (5.5%) were positive for CHA by %dCDT. Positive predictive value of AUDIT for CHA was 21.4%. There was no correlation between positive scores on AUDIT and %dCDT.

Discussion

Identifying at risk patients early on in their hospital course may allow clinicians to institute treatments to mitigate and/or circumvent complications in such patients. This pilot study determined that 17.6% of participating EGS patients were positive for some type of alcohol misuse, but only 5.5% had CHA. Further research is needed to determine whether routine use of %dCDT would be beneficial in reducing perioperative complications in this patient population.

Level of evidence

III (diagnostic test).

Transdiagnostic Effects of Ventromedial Prefrontal Cortex Transcranial Magnetic Stimulation on Cue Reactivity

BACKGROUND

Elevated frontal and striatal reactivity to drug cues is a transdiagnostic hallmark of substance use disorders. The goal of these experiments was to determine if it is possible to decrease frontal and striatal reactivity to drug cues in both cocaine users and heavy alcohol users through continuous theta burst stimulation (cTBS) to the left ventromedial prefrontal cortex (VMPFC).

METHODS

Two single-blinded, within-subject, active sham-controlled experiments were performed wherein neural reactivity to drug/alcohol cues versus neutral cues was evaluated immediately before and after receiving real or sham cTBS (110% resting motor threshold, 3600 pulses, Fp1 location; N = 49: 25 cocaine users [experiment 1], 24 alcohol users [experiment 2]; 196 total functional magnetic resonance imaging scans). Generalized psychophysiological interaction and three-way repeated-measures analysis of variance were used to evaluate cTBS-induced changes in drug cue-associated functional connectivity between the left VMPFC and eight regions of interest: ventral striatum, left and right caudate, left and right putamen, left and right insula, and anterior cingulate cortex.

RESULTS

In both experiments, there was a significant interaction between treatment (real/sham) and time (pre/post). In both experiments, cue-related functional connectivity was significantly attenuated following real cTBS versus sham cTBS. There was no significant interaction with region of interest for either experiment.

CONCLUSIONS

This is the first sham-controlled investigation to demonstrate, in two populations, that VMPFC cTBS can attenuate neural reactivity to drug and alcohol cues in frontostriatal circuits. These results provide an empirical foundation for future clinical trials that may evaluate the efficacy, durability, and clinical implications of VMPFC cTBS to treat addictions.

Nicotine-Use/Smoking Is Associated with the Efficacy of Naltrexone in the Treatment of Alcohol Dependence

BACKGROUND

The opioid antagonist naltrexone is not efficacious for every alcohol treatment seeker. However, various individual factors, such as genetic differences and nicotine-use/smoking status, have been suggested as predictors of naltrexone response. In a randomized clinical trial, we previously reported that nicotine-use/smoking status might be a stronger predictor of naltrexone efficacy than OPRM1 A118G single nucleotide polymorphism (SNP) genotype. In this report, we further characterize the nicotine-users in that trial, examine other drinking outcomes, examine the influence of smoking change on naltrexone effects on drinking, and validate the result in smokers with disialo carbohydrate-deficient transferrin (%dCDT) change as an independent biomarker of response.

METHODS

Individuals (n = 146) meeting DSM-IV criteria for alcohol dependence who were genotyped for the OPRM1 A118G SNP and who did, or did not, use nicotine/cigarettes were randomized, in a balanced fashion, to naltrexone (50 mg/d) or placebo and provided medical management (MM) over a 16-week clinical trial. Alcohol use and smoking during the trial were assessed and analyzed.

RESULTS

Nicotine-use/smoking status significantly interacted with medication in reducing percent heavy drinking days (PHDD) during the trial (p = 0.003), such that nicotine-users/smokers showed significantly lower PHDD on naltrexone versus placebo (p = 0.0001, Cohen's d = 0.89), while nonusers showed no significant difference between naltrexone and placebo (p = 0.95, Cohen's d = 0.02). Similar effects were shown for drinks per day and percent days drinking. The superiority of naltrexone over placebo on PHDD reduction in nicotine-users/smokers was confirmed with %dCDT (Cohen's d range 0.3 to 0.9 over the study). Naltrexone did not significantly change cigarette use in smokers, and change in use did not influence naltrexone's effect on PHDD.

CONCLUSIONS

These data confirm past findings that naltrexone is more efficacious in those who use nicotine/cigarettes. Compared to previous work on the OPRM1 A118G SNP, it appears that nicotine-use might be a more salient predictor of naltrexone treatment response. While naltrexone did not change cigarette use during the study, and smoking change was not related to alcohol reduction, it should be noted that participants were not seeking smoking cessation and MM did not address this issue.

Left frontal pole theta burst stimulation decreases orbitofrontal and insula activity in cocaine users and alcohol users

BACKGROUND

Preclinical research has demonstrated a causal relationship between medial prefrontal cortex activity and cocaine self-administration. As a step towards translating those data to a neural circuit-based intervention for patients, this study sought to determine if continuous theta burst stimulation (cTBS) to the left frontal pole (FP), would attenuate frontal-striatal activity in two substance-dependent populations.

METHODS

Forty-nine substance dependent individuals (25 cocaine, 24 alcohol) completed a single-blind, sham-controlled, crossover study wherein they received 6 trains of real or sham cTBS (110% resting motor threshold, FP1) each visit. Baseline evoked BOLD signal was measured immediately before and after real and sham cTBS (interleaved TMS/BOLD imaging: single pulses to left FP; scalp-to-cortex distance covariate, FWE correction p<0.05) RESULTS: Among cocaine users, real cTBS significantly decreased evoked BOLD signal in the caudate, accumbens, anterior cingulate, orbitofrontal (OFC) and parietal cortex relative to sham cTBS. Among alcohol users, real cTBS significantly decreased evoked BOLD signal in left OFC, insula, and lateral sensorimotor cortex. There was no significant difference between the groups.

CONCLUSIONS

These data suggest that 6 trains of left FP cTBS delivered in a single day decreases TMS-evoked BOLD signal in the OFC and several cortical nodes which regulate salience and are typically activated by drug cues. The reliability of this pattern across cocaine- and alcohol-dependent individuals suggests that cTBS may be an effective tool to dampen neural circuits typically engaged by salient drug cues. Multiday studies are required to determine it this has a sustainable effect on the brain or drug use behavior.

Unique prefrontal GABA and glutamate disturbances in co-occurring bipolar disorder and alcohol dependence

Bipolar disorder (BD) and alcohol dependence (AD) frequently co-occur, and co-occurring BD and AD are associated with devastating public health costs. Minimal neurobiological research exists to guide the development of effective treatments for this treatment-resistant population. We believe the present study represents the first investigation of prefrontal gamma-aminobutyric acid (GABA) and glutamate levels in co-occurring BD and current AD. The participants were 78 individuals who met DSM-IV criteria for BD I/II and current AD (n=20), BD I/II alone (n=19), current AD alone (n=20) or no diagnosis (n=19). The participants completed a baseline diagnostic visit, then returned approximately 4 days later for a two-dimensional J-resolved proton magnetic resonance spectroscopy (¹H-MRS) acquisition in dorsal anterior cingulate cortex (dACC). All participants were required to demonstrate ⩾1 week of abstinence from alcohol/drugs via serial biomarker testing before ¹H-MRS. A 2 × 2 factorial analysis of variance of cerebrospinal fluid (CSF)-corrected GABA/water concentrations demonstrated a significant BD × AD interaction (F=2.91, P<0.05), signifying uniquely low levels of GABA in BD+AD; this effect doubled when the sample was restricted to individuals who consumed alcohol within 2 weeks of ¹H-MRS. There were no overall effects of BD/AD on CSF-corrected glutamate/water levels. However, the BD × AD interaction, signifying uniquely low levels of glutamate in BD+AD, approached statistical significance (F=3.83, P=0.06) in individuals who consumed alcohol within 2 weeks of ¹H-MRS. The dACC GABA levels were significantly, negatively associated with Barratt Impulsiveness Scale (r=-0.28, P=0.02) and Obsessive Compulsive Drinking Scale (r=-0.35, P<0.01) scores. If replicated, these results may suggest that future treatment studies should preferentially evaluate therapeutics in BD+AD known to increase prefrontal GABA and glutamate levels.

Aripiprazole Suppression of Drinking in a Clinical Laboratory Paradigm: Influence of Impulsivity and Self-Control

BACKGROUND

Aspects of impulsivity have been implicated in the development, or maintenance, of alcohol use disorder (AUD). The brain dopamine system is implicated in both reward processing/memory (typically subcortical) and in brain inhibitory control mechanisms (typically cortical). Using a validated clinical laboratory paradigm, the dopamine/serotonin "stabilizing" drug, aripiprazole was evaluated in non-treatment-seeking AUD individuals based on their level of impulsivity/self-control.

METHODS

Ninety-nine individuals (77% male; mean age 27; 7.5 drinks per day; 83% heavy drinking days) meeting DSM-IV criteria for alcohol dependence were randomized to aripiprazole (N = 47 evaluable) or placebo (N = 48 evaluable) based on their Barratt Impulsiveness Scale (BIS-11) score (above or below 68). Aripiprazole, or similar placebo, was titrated to 15 mg over 8 days. Drinking was recorded over 6 days under natural conditions. On Day 8, after 1 day of required abstinence, individuals participated in a bar laboratory paradigm that included a priming drink (breath alcohol concentration [BAC] target 0.02 to 0.03 g/dl) and free-choice consumption of up to 8 drinks (max BAC 0.1 g/dl) in exchange for a "bar credit" of $2 per drink (max $16). End points were drinks per day under natural conditions and drinks consumed in the bar laboratory after the priming drink.

RESULTS

There was no significant main effect of aripiprazole or interaction with BIS-11 score during the natural drinking period. However, there was a main effect of aripiprazole on bar laboratory drinking (p = 0.04) and aripiprazole reduced the total number of drinks consumed more among individuals with low self-control (p = 0.034) and increased latency to consume those drinks (p = 0.045) more among those with high impulsivity. Relative to placebo, aripiprazole caused more side effects and increased alcohol-induced sedation, but neither significantly influenced its interaction with impulsivity/self-control scores on drinking.

CONCLUSIONS

This paradigm forced a choice between immediate drinking reward and delayed monetary reward. In those with high impulsivity and/or low self-control, aripiprazole shifts the balance away from immediate drinking toward a later reward. Medications targeting cortical dopamine/serotonin balance might show clinical benefit of reduced drinking, among individuals with impulsivity/low self-control.

Temporal Stability of Heavy Drinking Days and Drinking Reductions Among Heavy Drinkers in the COMBINE Study

BACKGROUND

Recently, the Food and Drug Administration (FDA) proposed to expand the options for primary end points in the development of medications for alcohol use disorder to include either abstinence from alcohol or a nonabstinent outcome: no heavy drinking days (with a heavy drinking day defined as more than 3 drinks per day for women and more than 4 drinks per day for men [>3/>4 cutoff]). The FDA also suggested that 6 months would be the most appropriate length for a clinical trial to demonstrate the stability of this nonabstinent drinking outcome. However, few alcohol clinical trials have examined the stability of nonheavy drinking during and after treatment.

METHODS

In a secondary analysis of the COMBINE study data (n = 1,383), we examined transitions in heavy drinking days during the course of treatment (months 1 through 4), during the transition out of treatment (months 4 through 7), and up to 12 months afterward (months 13 through 16) using latent variable mixture models.

RESULTS

Heavy drinking and nonheavy drinking were relatively stable in consecutive months (minimum agreement [kappa] = 0.64 for months 1 to 2). Most individuals were stable low-risk drinkers/abstainers or heavy drinkers by the end of treatment, as characterized by a 10% probability (or less) of transitioning out of either a no heavy drinking state or a heavy drinking state. More than two-thirds of the heavy drinkers who exceeded the heavy drinking threshold during treatment reported, on average, a 64% reduction in drinking frequency and a 38% reduction in drinking intensity from pretreatment drinking levels.

CONCLUSIONS

The results show stability of no heavy drinking as an outcome within the first 4 months of treatment and that the >3/>4 drink cutoff may mask substantial reductions in alcohol consumption among some patients. Future studies should explore the clinical utility of reduction end points.

Clinical Validation of Reduced Alcohol Consumption After Treatment for Alcohol Dependence Using the World Health Organization Risk Drinking Levels

Background

Alcohol use disorder (AUD) is a highly prevalent public health problem associated with considerable individual and societal costs. Abstinence from alcohol is the most widely accepted target of treatment for AUD, but it severely limits treatment options and could deter individuals who prefer to reduce their drinking from seeking treatment. Clinical validation of reduced alcohol consumption as the primary outcome of alcohol clinical trials is critical for expanding treatment options. One potentially useful measure of alcohol treatment outcome is a reduction in the World Health Organization (WHO, International Guide for Monitoring Alcohol Consumption and Related Harm. Geneva, Switzerland, 2000) risk levels of alcohol use (very high risk, high risk, moderate risk, and low risk). For example, a 2‐shift reduction in WHO risk levels (e.g., high risk to low risk) has been used by the European Medicines Agency (2010, Guideline on the Development of Medicinal Products for the Treatment of Alcohol Dependence. UK) to evaluate nalmefene as a treatment for alcohol dependence (AD; Mann et al. 2013, Biol Psychiatry 73, 706–13).

Methods

The current study was a secondary data analysis of the COMBINE study (n = 1,383; Anton et al., 2006) to examine the association between reductions in WHO risk levels and reductions in alcohol‐related consequences and mental health symptoms during and following treatment in patients with AD.

Results

Any reduction in WHO risk drinking level during treatment was associated with significantly fewer alcohol‐related consequences and improved mental health at the end of treatment and for up to 1 year posttreatment. A greater reduction in WHO risk drinking level predicted a greater reduction in consequences and greater improvements in mental health.

Conclusions

Changes in WHO risk levels appear to be a valid end point for alcohol clinical trials. Based on the current findings, reductions in WHO risk drinking levels during treatment reflect meaningful reductions in alcohol‐related consequences and improved functioning.

The Reasons for Heavy Drinking Questionnaire: Factor Structure and Validity in Alcohol-Dependent Adults Involved in Clinical Trials

OBJECTIVE

People consume alcohol at problematic levels for many reasons. These different motivational pathways may have different biological underpinnings. Valid, brief measures that discriminate individuals' reasons for drinking could facilitate inquiry into whether varied drinking motivations account for differential response to pharmacotherapies for alcohol use disorders. The current study evaluated the factor structure and predictive validity of a brief measure of alcohol use motivations developed for use in randomized clinical trials, the Reasons for Heavy Drinking Questionnaire (RHDQ).

METHOD

The RHDQ was administered before treatment to 265 participants (70% male) with alcohol dependence according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, in three pharmacotherapy randomized clinical trials. Principal components analysis was used in half the sample to determine the RHDQ factor structure. This structure was verified with confirmatory factor analysis in the second half of the sample. The factors derived from this analysis were evaluated with respect to alcohol dependence severity indices.

RESULTS

A two-factor solution was identified. Factors were interpreted as Reinforcement and Normalizing. Reinforcement scores were weakly to moderately associated with severity, whereas normalizing scores were moderately to strongly associated with severity. In all cases in which significant associations between RHDQ scores and severity indices were observed, the relationship was significantly stronger for normalizing than for reinforcing.

CONCLUSIONS

The RHDQ is a promising brief assessment of motivations for heavy alcohol use, particularly in the context of randomized clinical trials. Additional research should address factor structure stability in non-treatment-seeking individuals and the RHDQ's utility in detecting and accounting for changes in drinking behavior, including in response to intervention.

Relationship of Abnormal Chromatographic Pattern for Carbohydrate-Deficient Transferrin with Severe Liver Disease

AIMS

Serum carbohydrate-deficient transferrin (CDT) is a validated test for chronic heavy alcohol drinking, but CDT abnormalities have been associated with liver disease, limiting its use in these patients. We report here on the association between poor chromatographic resolution of disialotransferrin from trisialotransferrin (the so-called 'di-tri bridging') and liver disease severity and etiology.

METHODS

Subjects were patients in whom detailed clinical data, including histology results, were available on their existing liver diseases (n=139). Percent disialo-CDT (%dCDT) was measured by high-performance liquid chromatography, and the risks for di-tri bridging associated with cirrhosis, with and without adjustment for alcohol use and alcohol-related liver disease, were estimated.

RESULTS

Di-tri bridging was present in 22/73 (30%) cirrhotic subjects and 7/66 (11%) non-cirrhotic subjects. The unadjusted risk for di-tri bridging in cirrhotics relative to non-cirrhotics was 3.6 (95% confidence interval 1.4-9.2). Adjustment for alcohol-related liver disease and current drinking had little effect on this estimate (adjusted odds ratio 3.4), and neither alcohol-related liver disease nor current drinking were independently associated with di-tri bridging after accounting for the effect of cirrhosis.

CONCLUSIONS

The presence of di-tri bridging was associated with cirrhosis in individuals with both alcohol-related and non-alcoholic liver disease, although most cirrhotic subjects did not exhibit di-tri bridging. When di-tri bridging is seen in individuals being tested for chronic heavy drinking, investigation for cirrhosis should be considered.

SHORT SUMMARY

There are known liver-disease-associated abnormalities in CDT. In this study, we found that such abnormalities were strongly associated with cirrhosis rather than less-advanced disease, but were only clinically evident in 30% of cirrhotics. Abnormalities also occurred in severe hepatitis without cirrhosis and were not specific for liver disease etiology.

Missing Data in Alcohol Clinical Trials with Binary Outcomes

BACKGROUND

Missing data are common in alcohol clinical trials for both continuous and binary end points. Approaches to handle missing data have been explored for continuous outcomes, yet no studies have compared missing data approaches for binary outcomes (e.g., abstinence, no heavy drinking days). This study compares approaches to modeling binary outcomes with missing data in the COMBINE study.

METHODS

We included participants in the COMBINE study who had complete drinking data during treatment and who were assigned to active medication or placebo conditions (N = 1,146). Using simulation methods, missing data were introduced under common scenarios with varying sample sizes and amounts of missing data. Logistic regression was used to estimate the effect of naltrexone (vs. placebo) in predicting any drinking and any heavy drinking outcomes at the end of treatment using 4 analytic approaches: complete case analysis (CCA), last observation carried forward (LOCF), the worst case scenario (WCS) of missing equals any drinking or heavy drinking, and multiple imputation (MI). In separate analyses, these approaches were compared when drinking data were manually deleted for those participants who discontinued treatment but continued to provide drinking data.

RESULTS

WCS produced the greatest amount of bias in treatment effect estimates. MI usually yielded less biased estimates than WCS and CCA in the simulated data and performed considerably better than LOCF when estimating treatment effects among individuals who discontinued treatment.

CONCLUSIONS

Missing data can introduce bias in treatment effect estimates in alcohol clinical trials. Researchers should utilize modern missing data methods, including MI, and avoid WCS and CCA when analyzing binary alcohol clinical trial outcomes.

Association between a brief alcohol craving measure and drinking in the following week

BACKGROUND AND AIMS

Craving for alcohol is thought to be a predictor of alcohol use, particularly in the near future. The assessment of craving in clinical practice requires brief, simple measures that can be implemented routinely. This study tested whether greater alcohol craving was associated with a higher likelihood of alcohol use in the subsequent week.

DESIGN

The COMBINE Study (Combining Medications and Behavioral Interventions for Alcohol Dependence) was a large, multi-site clinical trial of treatment for alcohol dependence. Participants were randomized (stratified by site) to one of nine treatment conditions involving combinations of pharmacotherapy and psychotherapy. Craving was assessed every other week throughout the treatment period.

SETTING

Substance use disorder treatment settings at 11 academic sites across the United States.

PARTICIPANTS

Participants from the COMBINE Study (n = 1370) with available craving data.

MEASUREMENTS

Craving was assessed using the three-item self-report Craving Scale. Drinking was assessed using the Timeline Followback method, and was defined as alcohol use in each study week.

FINDINGS

There was an average of 5.8 (of a possible seven) observation pairs per participant. Craving was associated strongly with alcohol use in the following week [B = 0.27, standard error (SEB ) = 0.06, Wald χ(2)  = 43.34, odds ratio (OR) = 1.31, 95% confidence interval (CI) = 1.16, 1.47, P < 0.001]. For each 1-unit increase in the Craving Scale, the likelihood of drinking in the next week was 31% higher.

CONCLUSIONS

Craving for alcohol is associated strongly with alcohol use in the following week. Clinicians can measure alcohol craving effectively using a brief self-report craving scale.

Assessment and treatment of mood disorders in the context of substance abuse

Recognition and management of mood symptoms in individuals using alcohol and/or other drugs represent a daily challenge for clinicians in both inpatient and outpatient treatment settings. Diagnosis of underlying mood disorders in the context of ongoing substance abuse requires careful collection of psychiatric history, and is often critical for optimal treatment planning and outcomes. Failure to recognize major depression or bipolar disorders in these patients can result in increased relapse rates, recurrence of mood episodes, and elevated risk of completed suicide. Over the past decade, epidemiologic research has clarified the prevalence of comorbid mood disorders in substance-dependent individuals, overturning previous assumptions that depression in these patients is simply an artifact of intoxication and/or withdrawal, therefore requiring no treatment. However, our understanding of the bidirectional relationships between mood and substance use disorders in terms of their course(s) of illness and prognoses remains limited. Like-wise, strikingly little treatment research exists to guide clinical decision making in co-occurring mood and substance use disorders, given their high prevalence and public health burden. Here we overview what is known and the salient gaps of knowledge where data might enhance diagnosis and treatment of these complicated patients.

Alcohol-Induced Stimulation Mediates the Effect of a GABRA2 SNP on Alcohol Self-Administrated among Alcohol-Dependent Individuals

BACKGROUND

A single-nucleotide polymorphism (SNP) in GABRA2 (rs279858) may moderate subjective response (SR) to alcohol. Results of studies in non-dependent drinkers examining this GABRA2 SNP on SR have been equivocal. This study examined this SNP's direct and indirect effects on alcohol self-administration in dependent drinkers.

METHOD

The sample consisted of 63 Caucasian, non-treatment-seeking individuals with alcohol dependence. Subjective stimulation was assessed using the Biphasic Alcohol Effects Scale following consumption of an alcoholic priming drink (target breath alcohol content = 0.02 g%). Participants were subsequently offered the opportunity to self-administer up to eight additional drinks.

RESULTS

Controlling for baseline stimulation, T-allele homozygotes, relative to individuals with at least one copy of the C-allele, reported greater initial stimulation, t(58) = 2.011, p = 0.049. Greater stimulation predicted greater subsequent alcohol self-administration, t(57) = 2.522, p = 0.015. Although rs279858 genotype did not directly impact self-administration (t(57) = -0.674, p = 0.503), it did have an indirect effect (95% confidence interval [0.068, 1.576]), such that T-allele homozygotes reported greater stimulation, which in turn predicted greater self-administration.

CONCLUSION

These results suggest that the influence of this SNP on SR differs depending on dose or stage of dependence. This study is the first to demonstrate an indirect effect of rs279858 genotype on drinking through SR. Although C-allele carriers have been shown to have an increased risk for alcohol dependence, in our dependent sample, greater stimulation was found among T-allele homozygotes, suggesting that the influence of SR on developing and maintaining dependence differs based on rs279858 genotype.This study demonstrates an indirect effect of rs279858 genotype on drinking through SR. Although C-allele carriers have an increased risk for alcohol dependence, in our dependent sample, greater stimulation was found among T-allele homozygotes, suggesting that the influence of SR on developing dependence differs based on rs279858 genotype.

Associations Between Recent Heavy Drinking and Dorsal Anterior Cingulate N-Acetylaspartate and Glutamate Concentrations in Non-Treatment-Seeking Individuals with Alcohol Dependence

BACKGROUND

Proton magnetic resonance spectroscopy ((1) H-MRS) studies have consistently found abnormal brain concentrations of N-acetylaspartate (NAA) and glutamate in individuals with alcohol use disorders (AUD) relative to light drinkers. However, most such studies have focused on individuals in treatment for severe alcohol dependence (AD), and few studies have investigated associations between neurochemical concentrations and recent alcohol consumption. This study focused on associations between recent drinking and prefrontal neurometabolite concentrations in nonsevere, non-treatment-seeking individuals with AUD.

METHODS

Nineteen treatment-naïve alcohol-dependent individuals aged 21 to 40 completed a (1) H-MRS scan. Single-voxel (1) H-MRS spectra were acquired in dorsal anterior cingulate cortex (dACC) using a 2-dimensional J-resolved point resolved spectroscopy sequence. Associations between recent heavy drinking, assessed using the Timeline FollowBack, and dACC metabolite concentrations were estimated via regression controlling for within-voxel tissue composition.

RESULTS

Participants provided a negative breathalyzer reading and reported between 1 and 5 days (M = 2.45, SD = 1.23) since their last drink. Number of heavy drinking days in the 14 days preceding the scan (M = 4.84, SD = 3.32) was significantly inversely associated with both glutamate/water (β = -0.63, t(17) = -3.37, p = 0.004) and NAA/water concentrations (β = -0.59, t(17) = -2.98, p = 0.008).

CONCLUSIONS

This study extends the literature by demonstrating inverse associations between recent heavy drinking and dACC glutamate and NAA concentrations in a sample of nonsevere, non-treatment-seeking individuals with AD. These findings may support the hypothesis that amount of recent alcohol consumption may account for differences in neuronal metabolism, even in nonsevere, non-treatment-seeking alcoholics.

Methods to analyze treatment effects in the presence of missing data for a continuous heavy drinking outcome measure when participants drop out from treatment in alcohol clinical trials

BACKGROUND

Attrition is common in alcohol clinical trials and the resultant loss of data represents an important methodological problem. In the absence of a simulation study, the drinking outcomes among those who are lost to follow-up are not known. Individuals who drop out of treatment and continue to provide drinking data, however, may be a reasonable proxy group for making inferences about the drinking outcomes of those lost to follow-up.

METHODS

We used data from the COMBINE study, a multisite, randomized clinical trial, to examine drinking during the 4 months of treatment among individuals who dropped out of treatment but continued to provide drinking data (i.e., "treatment dropouts;" n = 185). First, we estimated the observed treatment effect size for naltrexone versus placebo in a sample that included both treatment completers (n = 961) and treatment dropouts (n = 185; total N = 1,146), as well as the observed treatment effect size among just those who dropped out of treatment (n = 185). In both the total sample (N = 1,146) and the dropout sample (n = 185), we then deleted the drinking data after treatment dropout from those 185 individuals to simulate missing data. Using the deleted data sets, we then estimated the effect of naltrexone on the continuous outcome percent heavy drinking days using 6 methods to handle missing data (last observation carried forward, baseline observation carried forward, placebo mean imputation, missing = heavy drinking days, multiple imputation (MI), and full information maximum likelihood [FIML]).

RESULTS

MI and FIML produced effect size estimates that were most similar to the true effects observed in the full data set in all analyses, while missing = heavy drinking days performed the worst.

CONCLUSIONS

Although missing drinking data should be avoided whenever possible, MI and FIML yield the best estimates of the treatment effect for a continuous outcome measure of heavy drinking when there is dropout in an alcohol clinical trial.

Cumulative proportion of responders analysis (CPRA) as a tool to assess treatment outcome in alcohol clinical trials

OBJECTIVE

Several definitions of treatment response have been proposed for alcohol clinical trials (e.g., abstinence and no heavy drinking). However, each of these outcomes allows only one definition of successful response. In contrast, the cumulative proportion of responders analysis (CPRA) includes all of the possible drinking response cutoff points, providing a more complete picture of the therapeutic effects of a treatment. CPRA has been used to examine the efficacy of analgesics but not alcohol pharmacotherapy. To demonstrate its potential utility, we conducted CPRA in two large alcohol treatment trials: the COMBINE (Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence) trial (naltrexone) and a multisite topiramate trial. CPRA was used to demonstrate the efficacy of naltrexone and topiramate on continuous measures of in-treatment drinking-heavy drinking days and drinks per day-and their reductions from pretreatment.

METHOD

All possible cutoff points were portrayed for each measure. We provide graphs to illustrate the effects of the active medications compared with placebo and examined them statistically over a number of salient drinking outcomes to evaluate their efficacy.

RESULTS

Treatment group responder curves were not parallel across the entire range of cutoff points; rather, they separated only at lower levels of drinking. In general, effect sizes increased by 0.10-0.15 when going from the lowest drinking level cutoff (i.e., abstinence and no heavy drinking) to the cutoff associated with the maximal treatment effect.

CONCLUSIONS

CPRA may be useful in designing subsequent trials and helping to illustrate for treatment providers the likelihood of treatment success given various definitions of a positive response.

Harmonization of Measurement Results of the Alcohol Biomarker Carbohydrate-Deficient Transferrin by Use of the Toolbox of Technical Procedures of the International Consortium for Harmonization of Clinical Laboratory Results

BACKGROUND

The need for equivalent results of routine measurement procedures for the alcohol biomarker carbohydrate-deficient transferrin (CDT) has been recognized by the IFCC. This article describes a project to harmonize CDT as conducted by an IFCC working group initiated for this purpose.

METHODS

We used procedures for achieving harmonization as developed by the Consortium for Harmonization of Clinical Laboratory Results to assess the suitability of a candidate reference measurement procedure (cRMP), candidate reference materials (cRMs), and the success of efforts to achieve harmonization.

RESULTS

CDT measurement procedures in routine use showed good reproducibility (CV 1.1%–2.8%) and linearity (r &gt; 0.990) with variable slopes (0.766–1.065) and intercepts (−0.34 to 0.92) compared to the cRMP. Heterogeneity after simulated harmonization was 4.7%. cRMs of frozen human native sera demonstrated commutability and 3-year stability for routine measurement procedures. The cRMP provided reproducible value assignment to cRMs with an expanded uncertainty (k = 2) of 0.03% at the 1.2% CDT level and 0.06% at the 4.4% CDT level. Harmonization efforts reduced the intermeasurement CV from 8.8% to 3.4%, allowed 99% recovery of the values assigned with the cRMP, and demonstrated 99% of results within the desirable allowable total error. Harmonization was less successful in samples with low CDT and high trisialotransferrin concentrations.

CONCLUSIONS

Harmonization of CDT is possible with frozen human native sera as cRMs with values assigned by use of the cRMP. We propose the cRMP as a candidate international conventional reference measurement procedure and cRMs as candidate international calibrators.

Validation of blood phosphatidylethanol as an alcohol consumption biomarker in patients with chronic liver disease

BACKGROUND

Blood phosphatidylethanol (PEth) is a promising biomarker of alcohol consumption. This study was conducted to evaluate its performance in patients with liver disease.

METHODS

This study included 222 patients with liver disease. Patient-reported alcohol use was obtained as a reference standard, and PEth was measured by tandem mass spectrometry. Receiver operating characteristic (ROC) and contingency table analyses were used to assess the performance of PEth in detecting any drinking and averaging 4 or more drinks daily in the past 30 days.

RESULTS

At the limit of quantitation (20 ng/ml), PEth was 73% sensitive (95% confidence interval [CI] 65 to 80) and 96% specific (95% CI 92 to 100) for any drinking in the past month. Subjects who drank but had a negative PEth result were mainly light drinkers. Subjects who reported 30-day abstinence but with quantifiable PEth either reported heavy drinking within the past 6 weeks or had data that suggested underreported drinking. At the optimal cutoff concentration of 80 ng/ml, PEth was 91% sensitive (95% CI 82 to 100) and 77% specific (95% CI 70 to 83) for averaging at least 4 drinks daily.

CONCLUSIONS

PEth is a useful test for detecting alcohol use in patients with liver disease, but cutoff concentrations for heavy drinking will result in misclassification of some moderate to heavy drinkers.