Genetic markers associated with abstinence length in alcohol-dependent subjects treated with acamprosate

Low-dose ondansetron: A candidate prospective precision medicine to treat alcohol use disorder endophenotypes

BACKGROUND

Alcohol use disorder (AUD) is among the leading causes of morbidity and mortality worldwide, and over 95 million people live with alcohol dependence globally. The estimated heritability of AUD is 50-60 %, and multiple genes are thought to contribute to various endophenotypes of the disease. Previous clinical trials support a precision medicine approach using ondansetron (AD04, a 5-HT3 antagonist) by segregating AUD populations by the bio-genetic endophenotype of specific serotonergic genotypes and the bio-psychosocial endophenotype of the severity of drinking or both. By targeting the modulation of biogenetic signaling within the biopsychosocial context of AUD, low-dose AD04 holds promise in reducing alcohol consumption among affected individuals while minimizing adverse effects.

METHODS

This was a phase III, 6-month, 25-site, randomized, placebo-controlled clinical trial using AD04 to treat DSM-V-categorized AUD individuals who were pre-stratified into the endophenotypes of heavy or very heavy drinking individuals and possessed a pre-defined profile of genetic variants related to the serotonin transporter and serotonin-3AB receptor. Participants (N = 303) presented moderate to severe AUD, >80 % were men, mostly in their fifties, and >95 % were of European descent. Low-dose AD04 (approx. 033 mg twice daily) or a matching placebo was administered twice daily for 6 months. Brief Behavioral Compliance Enhancement Treatment (BBCET [53]) was administered every two weeks to enhance medication compliance and clinic attendance.

RESULTS

There was a significant reduction in the monthly percentage of heavy drinking days, PHDD (-46·7 % (2·7 %), 95 %CI: -52·1 % to -41·2 % vs. -38·1 % (2·9 %), 95 %CI: -43·8 % to -32·5 %, respectively; LS mean difference=-8·5 %; p = 0.03) among AD04-treated vs. placebo-receiving heavy drinking individuals at month 6. Heavy drinking individuals were also less likely to be diagnosed with AUD [Month 1: -32·0 % (2·8 %), 95 %CI: -37·5 % to -26·5 % vs. -23·2 % (2·9 %), 95 %CI: -28·9 to -17·5 %; LS mean difference= -8·8 %; p = 0·026)], and improved on the WHO quality of life BREF scale with a significant effect for at least a 1-level downward shift (OR = 3.4; 95 % CI: 1·03-11·45, p = 0·044). Importantly, heavy drinking individuals, as distinct from very heavy drinking individuals, were the bio-psychosocial endophenotype more predictive of therapeutic response to AD04. AD04 had an exceptional safety and tolerability profile, like the placebo's.

CONCLUSIONS

In this Phase 3 clinical trial, AD04 was shown to be a promising treatment for currently drinking heavy drinking individuals with AUD who also possess a specific genotypic profile in the serotonin transporter and serotonin-3AB receptor complex. Using AD04 to reduce the harm of AUD in heavy drinking individuals who are currently drinking, without the necessity of abstinence or detoxification from alcohol use, is an important advance in the field of precision medicine. AD04's adverse events profile, which was like placebo, should enhance accessibility and acceptance of modern medical treatment for AUD by lowering the incorrect but commonly perceived stigma of personal failure.

IL17RB genetic variants are associated with acamprosate treatment response in patients with alcohol use disorder: A proteomics-informed genomics study

Acamprosate is a Food and Drug Administration (FDA) approved medication for the treatment of alcohol use disorder (AUD). However, only a subset of patients achieves optimal treatment outcomes. Currently, no biological measures are utilized to predict response to acamprosate treatment. We applied our established pharmaco-omics informed genomics strategy to identify potential biomarkers associated with acamprosate treatment response. Specifically, our previous open-label acamprosate clinical trial recruited 442 patients with AUD who were treated with acamprosate for three months. We first performed proteomics using baseline plasma samples to identify potential biomarkers associated with acamprosate treatment outcomes. Next, we applied our established "proteomics-informed genome-wide association study (GWAS)" research strategy, and identified 12 proteins, including interleukin-17 receptor B (IL17RB), associated with acamprosate treatment response.​ A GWAS for IL17RB concentrations identified several genome-wide significant signals. Specifically, the top hit single nucleotide polymorphism (SNP) rs6801605 with a minor allele frequency of 38% in the European American population mapped 4 kilobase (Kb) upstream of IL17RB, and intron 1 of the choline dehydrogenase (CHDH) gene on chromosome 3 (p: 4.8E-20). The variant genotype (AA) for the SNP rs6801605 was associated with lower IL17RB protein expression. In addition, we identified a series of genetic variants in IL17RB that were associated with acamprosate treatment outcomes. Furthermore, the variantgenotypes for all of those IL17RB SNPs were protective for alcohol relapse. Finally, we demonstrated that the basal level of mRNA expression of IL17RB was inversely correlated with those of nuclear factor-κB (NF-κB) subunits, and a significantly higher expression of NF-κB subunits was observed in AUD patients who relapsed to alcohol use. In summary, this study illustrates that IL17RB genetic variants might contribute to acamprosate treatment outcomes. This series of studies represents an important step toward generating functional hypotheses that could be tested to gain insight into mechanisms underlying acamprosate treatment response phenotypes. (The ClinicalTrials.gov Identifier: NCT00662571).

Molecular mechanisms involved in alcohol craving, IRF3, and endoplasmic reticulum stress: a multi-omics study

Alcohol use disorder (AUD) is the most prevalent substance use disorder worldwide. Acamprosate and naltrexone are anti-craving drugs used in AUD pharmacotherapy. However, molecular mechanisms underlying their anti-craving effect remain unclear. This study utilized a patient-derived induced pluripotent stem cell (iPSC)-based model system and anti-craving drugs that are used to treat AUD as "molecular probes" to identify possible mechanisms associated with alcohol craving. We examined the pathophysiology of craving and anti-craving drugs by performing functional genomics studies using iPSC-derived astrocytes and next-generation sequencing. Specifically, RNA sequencing performed using peripheral blood mononuclear cells from AUD patients with extreme values for alcohol craving intensity prior to treatment showed that inflammation-related pathways were highly associated with alcohol cravings. We then performed a genome-wide assessment of chromatin accessibility and gene expression profiles of induced iPSC-derived astrocytes in response to ethanol or anti-craving drugs. Those experiments identified drug-dependent epigenomic signatures, with IRF3 as the most significantly enriched motif in chromatin accessible regions. Furthermore, the activation of IRF3 was associated with ethanol-induced endoplasmic reticulum (ER) stress which could be attenuated by anti-craving drugs, suggesting that ER stress attenuation might be a target for anti-craving agents. In conclusion, we found that craving intensity was associated with alcohol consumption and treatment outcomes. Our functional genomic studies suggest possible relationships among craving, ER stress, IRF3 and the actions of anti-craving drugs.

DNA methylation at DLGAP2 and risk for relapse in alcohol dependence during acamprosate treatment

BACKGROUND

Alcohol use disorders are prevalent mental disorders with significant health implications. Epigenetic alterations may play a role in their pathogenesis, as DNA methylation at several genes has been associated with these disorders. We have previously shown that methylation in the DLGAP2 gene, coding for a synaptic density protein, is associated with alcohol dependence. In this study, we aimed to examine the association between DLGAP2 methylation and treatment response among patients undergoing acamprosate treatment.

METHODS

102 patients under acamprosate treatment were included. DNA methylation analysis at DLGAP2 was performed by bisulfite pyrosequencing at the start and after 3-month treatment. Treatment outcomes were having a relapse during the treatment and severity of craving at the end of three months. Cox proportional hazard and linear regression models were performed.

RESULTS

Patients whose methylation levels were decreased during the treatment showed an increased risk for relapse within three months in comparison to the ones without methylation change (hazard ratio [HR]=2.44; 95% confidence interval [CI]=1.04, 5.73; p=0.04). For the same group, a positive association for the severity of craving was observed, yet statistical significance was not reached (β=2.97; 95% CI=-0.41, 6.34; p=0.08).

CONCLUSION

We demonstrate that patients whose DLGAP2 methylation levels decrease during acamprosate treatment are more likely to relapse compared to the ones without changes. This is in line with our previous findings showing that DLGAP2 methylation is lower in alcohol dependent subjects compared to controls, and might suggest a role for changes in DLGAP2 methylation in treatment response.

Medications for treating alcohol use disorder: A narrative review

Chronic heavy alcohol use impacts all major neurotransmitter systems and is associated with multiple medical, psychiatric, and social problems. Available evidence-based medications to treat alcohol use disorder (AUD) are underutilized in clinical practice. These medications promote abstinence or reduce alcohol consumption, though there are questions regarding their optimal dosage, length of treatment, and utility in combination with one another. Pharmacogenetic approaches, which use a patient's genetic make-up to inform medication selection, have garnered great interest but have yet to yield results robust enough to incorporate them in routine clinical care. This narrative review summarizes the evidence both for medications approved by the Food and Drug Administration (disulfiram, oral naltrexone, acamprosate, and extended-release naltrexone) and those commonly used off-label (e.g., gabapentin, baclofen, and topiramate) for AUD treatment. We discuss these drugs' mechanisms of action, clinical use, pharmacogenetic findings, and treatment recommendations. We conclude that the most consistent evidence supporting the pharmacotherapy of AUD is for the opioid antagonists, naltrexone and nalmefene (which is not approved in the United States), and topiramate. These medications demonstrate consistent small or moderate effects in reducing the frequency of drinking and/or heavy drinking. Lastly, we make suggestions for research needed to refine and expand the current literature on effective pharmacotherapy for AUD.

The Interaction Between Brain-Derived Neurotrophic Factor Levels and Alcohol Consumption, Sleep Disturbance and Sex-Hormones in Alcohol Use Disorders

AIMS

Brain-derived neurotrophic factor (BDNF) levels may be associated with alcohol use disorders (AUD) and alcohol consumption, correlate with sleep disturbance and be influenced by sex differences and sex hormones. These associations have not been examined in a single sample accounting for all these factors.

METHODS

Data from 190 participants (29.4% female) with AUD were utilized. Sleep quality, craving intensity, depression, anxiety and alcohol consumption were assessed using the Pittsburgh Sleep Quality Index (PSQI), Penn Alcohol Craving Scale (PACS), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7) and Timeline Follow Back for 90 days(TLFB 90). Inventory of Drug Taking Situations (IDTS) assessed the tendency to drink in positive/negative emotional states. Serum BDNF (sBDNF) and plasma sex hormones (estrogen, progesterone, testosterone, FSH and SHBG) were measured. Pearson correlation analyses were used to examine the association between sBDNF and these measures in the entire sample and in men and women separately. Higher order interaction effects between these factors were evaluated for their association with sBDNF using a backward selection model.

RESULTS

No significant correlations between sBDNF levels and sex hormones, PSQI, PHQ-9, PACS, IDTS scores and alcohol consumption were found (all P-values > 0.05). sBDNF levels were negatively correlated with GAD-7 scores in men (r = -0.1841; P = 0.03). When considering all quadratic and two-way interactions among PSQI, PHQ-9, GAD-7, mean and max drinks/day, number of drinking days, heavy drinking days, and sex no higher order moderating effects of sBDNF levels were found.

CONCLUSION

Our study revealed no significant associations between sBDNF and alcohol measures, sleep, depression and sex hormones suggesting limited utility as a biomarker.

Genetic predisposition to major depressive disorder differentially impacts alcohol consumption and high-risk drinking situations in men and women with alcohol use disorder

Lifetime history of major depressive disorder (MDD) has a sex-specific association with pretreatment alcohol consumption in patients with alcohol dependence. Here, we investigated the association of genetic load for MDD estimated using a polygenic risk score (PRS) with pretreatment alcohol consumption assessed with Timeline Follow Back in a sample of 287 men and 156 women meeting DSM-IV-TR criteria for alcohol dependence. Preferred drinking situations were assessed using the Inventory of Drug Taking Situations (IDTS). Linear models were used to test for association of normalized alcohol consumption measures with the MDD-PRS, adjusting for ancestry, age, sex, and number of days sober at baseline. We fit models both with and without adjustment for MDD history and alcohol-use-related PRSs as covariates. Higher MDD-PRS was associated with lower 90-day total alcohol consumption in men (β = -0.16, p = 0.0012) but not in women (β = 0.11, p = 0.18). The association of MDD-PRS with IDTS measures was also sex-specific: higher MDD-PRS was associated with higher propensity to drink in temptation-related situations in women, while the opposite (negative association)was found in men. MDD-PRS was not associated with lifetime MDD history in our sample, and adjustment for lifetime MDD and alcohol-related PRSs did not impact the results. Our results suggest that genetic load for MDD impacts pretreatment alcohol consumption in a sex-specific manner, which is similar to, but independent from, the effect of history of MDD. The clinical implications of these findings and contributing biological and psychological factors should be investigated in future studies.

Association of polymorphic variants of <i>GRIN2A</i> and <i>GRIN2B</i> genes with alcohol and tobacco abuse in patients with schizophrenia

Aim. To compare the frequency of genotypes for polymorphic variants of GRIN2A and GRIN2B genes in patients with schizophrenia and addictive behavior (alcohol / tobacco abuse) and in patients with schizophrenia without addictive behavior in the Slavic population of the Tomsk region.

Materials and methods. The study included 219 inpatients with the established diagnosis of schizophrenia who received treatment in the clinics of Mental Health Research Institute and Tomsk Clinical Psychiatric Hospital. A history of alcohol / tobacco abuse was identified during a clinical interview and objective data collection. DNA was isolated from peripheral blood leukocytes by standard phenol – chloroform extraction.

15 single nucleotide polymorphisms (SNPs) in the GRIN2A gene and 9 polymorphisms in the GRIN2B gene were selected for genotyping. Allelic variants were determined by real-time polymerase chain reaction (PCR) with specific primers. The SPSS 17.0 software package was used for statistical data processing. The distribution of genotype frequency was assessed using the Pearson’s χ2 test with the Yates’ correction and the Fisher’s exact test.

Results. Significant differences in the allele frequency for the rs9788936 polymorphism in the GRIN2A gene (χ2 = 4.23, p = 0.04) and for the rs10845838 polymorphism in the GRIN2B gene (χ2 = 4.27, p = 0.04) were reveled between the groups of patients with and without alcohol abuse. It was found that the polymorphic variant rs8049651 of the GRIN2A gene had a clear association (F = 8.06, p = 0.029) with the development of tobacco addiction in patients with schizophrenia.

Conclusion. The study identified the association between alcohol abuse and the rs9788936 polymorphism in the GRIN2A gene and the rs10845838 polymorphism in the GRIN2B gene in patients with schizophrenia. The association between the rs8049651 and rs7190619 polymorphisms in the GRIN2A gene and the development of tobacco abuse in patients with schizophrenia was revealed.

Plasma TNFSF10 levels associated with acamprosate treatment response in patients with alcohol use disorder

Acamprosate is an anti-craving drug used in alcohol use disorder (AUD) pharmacotherapy. However, only a subset of patients achieves optimal treatment outcomes. The identification of predictive biomarkers of acamprosate treatment response in patients with AUD would be a substantial advance in addiction medicine. We designed this study to use proteomics data as a quantitative biological trait as a step toward identifying inflammatory modulators that might be associated with acamprosate treatment outcomes. The NIAAA-funded Mayo Clinic Center for the Individualized Treatment of Alcoholism study had previously recruited 442 AUD patients who received 3 months of acamprosate treatment. However, only 267 subjects returned for the 3-month follow-up visit and, as a result, had treatment outcome information available. Baseline alcohol craving intensity was the most significant predictor of acamprosate treatment outcomes. We performed plasma proteomics using the Olink target 96 inflammation panel and identified that baseline plasma TNF superfamily member 10 (TNFSF10) concentration was associated with alcohol craving intensity and variation in acamprosate treatment outcomes among AUD patients. We also performed RNA sequencing using baseline peripheral blood mononuclear cells from AUD patients with known acamprosate treatment outcomes which revealed that inflammation-related pathways were highly associated with relapse to alcohol use during the 3 months of acamprosate treatment. These observations represent an important step toward advancing our understanding of the pathophysiology of AUD and molecular mechanisms associated with acamprosate treatment response. In conclusion, applying omics-based approaches may be a practical approach for identifying biologic markers that could potentially predict alcohol craving intensity and acamprosate treatment response.

Genome-wide association study for circulating FGF21 in patients with alcohol use disorder: Molecular links between the SNHG16 locus and catecholamine metabolism

Objective

Alcohol consumption can increase circulating levels of fibroblast growth factor 21 (FGF21). The effects of FGF21 in the central nervous system are associated with the regulation of catecholamines, neurotransmitters that play a crucial role in reward pathways. This study aims to identify genetic variants associated with FGF21 levels and evaluate their functional role in alcohol use disorder (AUD).

Methods

We performed a genome-wide association study (GWAS) using DNA samples from 442 AUD subjects recruited from the Mayo Clinic Center for the Individualized Treatment of Alcoholism Study. Plasma FGF21 levels were measured using Olink proximity extension immunoassays. Alcohol consumption at time of entry into the study was measured using the self-reported timeline followback method. Functional genomic studies were performed using HepG2 cells and induced pluripotent stem cell (iPSC)-derived brain organoids.

Results

Plasma FGF21 levels were positively correlated with recent alcohol consumption and gamma-glutamyl transferase levels, a commonly used marker for heavy alcohol use. One variant, rs9914222, located 5’ of SNHG16 on chromosome 17 was associated with plasma FGF21 levels (p = 4.60E-09). This variant was also associated with AUD risk (β: −3.23; p:0.0004). The rs9914222 SNP is an eQTL for SNHG16 in several brain regions, i.e., the variant genotype was associated with decreased expression of SNHG16. The variant genotype for the rs9914222 SNP was also associated with higher plasma FGF21 levels. Knockdown of SNHG16 in HepG2 cells resulted in increased FGF21 concentrations and decreased expression and enzyme activity for COMT, an enzyme that plays a key role in catecholamine metabolism. Finally, we demonstrated that ethanol significantly induced FGF21, dopamine, norepinephrine, and epinephrine concentrations in iPSC-derived brain organoids.

Conclusions

GWAS for FGF21 revealed a SNHG16 genetic variant associated with FGF21 levels which are associated with recent alcohol consumption. Our data suggest that SNHG16 can regulate FGF21 concentrations and decrease COMT expression and enzyme activity which, in turn, have implications for the regulation of catecholamines.

(The ClinicalTrials.gov Identifier: NCT00662571)

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Plasma FGF21 levels are positively associated with recent alcohol use.

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GWAS for FGF21 revealed a SNHG16 genetic variant which might be associated with AUD.

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The rs9914222 SNP was an eQTL for SNHG16 in several brain regions.

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Ethanol could regulate SNHG16 expression, FGF21 levels and catecholamines.

Genetic Variants Associated with Acamprosate Treatment Response in Alcohol Use Disorder Patients: A Multiple Omics Study

Background and Purpose

Acamprosate is an anti‐craving drug used for the pharmacotherapy of alcohol use disorder (AUD). However, only some patients achieve optimal therapeutic outcomes. This study was designed to explore differences in metabolomic profiles between patients who maintained sobriety and those who relapsed, to determine whether those differences provide insight into variation in acamprosate treatment response phenotypes.

Experimental Approach

We previously conducted an acamprosate trial involving 442 AUD patients, and 267 of these subjects presented themselves for a 3‐month follow‐up. The primary outcome was abstinence. Clinical information, genomic data and metabolomics data were collected. Baseline plasma samples were assayed using targeted metabolomics.

Key Results

Baseline plasma arginine, threonine, α‐aminoadipic acid and ethanolamine concentrations were associated with acamprosate treatment outcomes and baseline craving intensity, a measure that has been associated with acamprosate treatment response. We next applied a pharmacometabolomics‐informed genome‐wide association study (GWAS) strategy to identify genetic variants that might contribute to variations in plasma metabolomic profiles that were associated with craving and/or acamprosate treatment outcome. Gene expression data for induced pluripotent stem cell‐derived forebrain astrocytes showed that a series of genes identified during the metabolomics‐informed GWAS were ethanol responsive. Furthermore, a large number of those genes could be regulated by acamprosate. Finally, we identified a series of single nucleotide polymorphisms that were associated with acamprosate treatment outcomes.

Conclusion and Implications

These results serve as an important step towards advancing our understanding of disease pathophysiology and drug action responsible for variation in acamprosate response and alcohol craving in AUD patients.

Genetic contributions to alcohol use disorder treatment outcomes: a genome-wide pharmacogenomics study

Naltrexone can aid in reducing alcohol consumption, while acamprosate supports abstinence; however, not all patients with alcohol use disorder (AUD) benefit from these treatments. Here we present the first genome-wide association study of AUD treatment outcomes based on data from the COMBINE and PREDICT studies of acamprosate and naltrexone, and the Mayo Clinic CITA study of acamprosate. Primary analyses focused on treatment outcomes regardless of pharmacological intervention and were followed by drug-stratified analyses to identify treatment-specific pharmacogenomic predictors of acamprosate and naltrexone response. Treatment outcomes were defined as: (1) time until relapse to any drinking (TR) and (2) time until relapse to heavy drinking (THR; ≥ 5 drinks for men, ≥4 drinks for women in a day), during the first 3 months of treatment. Analyses were performed within each dataset, followed by meta-analysis across the studies (N = 1083 European ancestry participants). Single nucleotide polymorphisms (SNPs) in the BRE gene were associated with THR (min p = 1.6E-8) in the entire sample, while two intergenic SNPs were associated with medication-specific outcomes (naltrexone THR: rs12749274, p = 3.9E-8; acamprosate TR: rs77583603, p = 3.1E-9). The top association signal for TR (p = 7.7E-8) and second strongest signal in the THR (p = 6.1E-8) analysis of naltrexone-treated patients maps to PTPRD, a gene previously implicated in addiction phenotypes in human and animal studies. Leave-one-out polygenic risk score analyses showed significant associations with TR (p = 3.7E-4) and THR (p = 2.6E-4). This study provides the first evidence of a polygenic effect on AUD treatment response, and identifies genetic variants associated with potentially medication-specific effects on AUD treatment response.

TSPAN5 influences serotonin and kynurenine: pharmacogenomic mechanisms related to alcohol use disorder and acamprosate treatment response

We previously reported that SNPs near TSPAN5 were associated with plasma serotonin (5-HT) concentrations which were themselves associated with selective serotonin reuptake inhibitor treatment outcomes in patients with major depressive disorder (MDD). TSPAN5 SNPs were also associated with alcohol consumption and alcohol use disorder (AUD) risk. The present study was designed to explore the biological function of TSPAN5 with a focus on 5-HT and kynurenine concentrations in the tryptophan pathway. Ethanol treatment resulted in decreased 5-HT concentrations in human induced pluripotent stem cell (iPSC)-derived neuron culture media, and the downregulation of gene expression of TSPAN5, DDC, MAOA, MAOB, TPH1, and TPH2 in those cells. Strikingly, similar observations were made when the cells were treated with acamprosate-an FDA approved drug for AUD therapy. These results were replicated in iPSC-derived astrocytes. Furthermore, TSPAN5 interacted physically with proteins related to clathrin and other vesicle-related proteins, raising the possibility that TSPAN5 might play a role in vesicular function in addition to regulating expression of genes associated with 5-HT biosynthesis and metabolism. Downregulation of TSPAN5 expression by ethanol or acamprosate treatment was also associated with decreased concentrations of kynurenine, a major metabolite of tryptophan that plays a role in neuroinflammation. Knockdown of TSPAN5 also influenced the expression of genes associated with interferon signaling pathways. Finally, we determined that TSPAN5 SNPs were associated with acamprosate treatment outcomes in AUD patients. In conclusion, TSPAN5 can modulate the concentrations of 5-HT and kynurenine. Our data also highlight a potentially novel pharmacogenomic mechanism related to response to acamprosate.

Evidence-Based Pharmacotherapies for Alcohol Use Disorder: Clinical Pearls

Pathologic alcohol use affects more than 2 billion people and accounts for nearly 6% of all deaths worldwide. There are three medications approved for the treatment of alcohol use disorder by the US Food and Drug Administration (FDA): disulfiram, naltrexone (oral and long-acting injectable), and acamprosate. Of growing interest is the use of anticonvulsants for the treatment of alcohol use disorder, although currently none are FDA approved for this indication. Baclofen, a γ-aminobutyric acid B receptor agonist used for spasticity and pain, received temporary approval for alcohol use disorder in France. Despite effective pharmacotherapies, less than 9% of patients who undergo any form of alcohol use disorder treatment receive pharmacotherapies. Current evidence does not support the use of pharmacogenetic testing for treatment individualization. The objective of this review is to provide knowledge on practice parameters for evidenced-based pharmacologic treatment approaches in patients with alcohol use disorder.

Pharmacotherapies and personalized medicine for alcohol use disorder: a review

Alcohol use disorder (AUD) is highly prevalent and among the leading causes of morbidity and mortality in the United States. Pharmacotherapies for AUD are limited, thus making identification of patient subgroups that are most likely to respond favorably crucial. In this article, pharmacogenetic research on US FDA-approved and commonly prescribed off-label medications for the treatment of AUD is comprehensively reviewed. While the field has advanced in understanding pharmacotherapies for AUD and potential genetic moderators of treatment responses, the pharmacogenetic data to guide the prescribing clinician are limited and should be interpreted with caution. Precision medicine for AUD with more beneficial treatment responses and minimal side effects remains a high priority for further research.

[A double blind placebo controlled randomized clinical trial of the efficacy and safety of pregabalin in induction of remission in patients with alcohol dependence]

AIM

To study the efficacy of pregabalin for relapse prevention and reduction of drinking in patients with alcohol dependence.

MATERIAL AND METHODS

One hundred recently detoxified out-patients with alcohol dependence were randomly assigned to one of two treatment groups. Patients of the first group (n=50; 38 men, 12 women, age 43.0±1.27) received pregabalin (150 mg once a day at night time) for 3 months, while patients of the second group (n=50; 45 men, 5 women, age 45.92±1.4) received identically looking placebo. All patients received standardized manualized weekly counseling (medical management). Drinking was measured on the weekly basis with Time Line Follow Back technique and GGT enzyme activity. Also, craving for alcohol, depression, and anxiety were measured weekly with the number of scales.

RESULTS

Kaplan-Meier survival analysis demonstrated significantly higher retention in treatment and in remission in the pregabalin group (lower drop out and relapse rate) mediana (CL)-12 (10.4-13.6) weeks in the pregabalin group vs. 6 (4.5-7.5) in the placebo group, Log Rank Mantel-Cox test = 0.005). Proportion of patients, who completed treatment in the pregabalin group, was significantly higher compared to the placebo group: 50% vs. 24%. Mean duration of participation in the treatment program was also higher in the pregabalin group: 9.1±0.5 weeks vs. 7.1±0.5 in the placebo group. General linear model demonstrated the significant treatment group effect on: (1) total alcohol consumption (TAC) (mean grams of alcohol per day) with lower TAC in the pregabalin group and (2) on the number of heavy drinking days (NHDD) with lower NHDD in the pregabalin group. Mean NHDD per patient for the period of participation in the study was lower in the pregabalin group (3.6±0.7 vs. 6.4±0.8; p=0.009), while the mean number of abstinent (sober) days was higher (55.9±3.6 vs. 40.0±3.3; p=0.001). No significant differences between the two groups were found in the scores on craving for alcohol, depression and anxiety scales. GGT activity was also similar in both groups throughout the study with no significant between group differences. The rate of adverse events (sleepiness, dizziness, and headache) was insignificantly higher in the pregabalin group compared with the placebo group. All adverse events were mild, gradually disappeared, and did not require any medication.

CONCLUSION

Results of this study provide evidence that pregabalin in a low dose of 150 mg per day is an effective and safe medication for relapse prevention and reduction of drinking in patients with alcohol dependence.

Sleep disturbances in early alcohol recovery: Prevalence and associations with clinical characteristics and severity of alcohol consumption

AIMS

We aimed to assess the prevalence of sleep disturbance in early alcohol recovery and its association with psychiatric comorbidity, cravings, propensity and severity of alcohol consumption.

DESIGN

The sample consisted of 18-80 year old patients (n = 303) receiving treatment for alcohol dependence. Sleep disturbance was measured using the Pittsburgh Sleep Quality Index (PSQI). Additional measures included PHQ-9, GAD-7 and Penn alcohol cravings scale (PACS), Inventory of Drug Taking Situations (IDTS) and alcohol consumption was measured utilizing the Time Line Follow Back (TLFB).Bivariate analyses evaluated the association between PSQI total score and other clinical characteristics. A multivariable model was computed for sleep disturbance with predictors entered into the model using automated stepwise selection.

FINDINGS

The sample was majority male (66%), White (93%) with a mean age of 42.2 ± 11.6 years. Baseline PSQI score was 10.2 ± 4.13 and most subjects (88%) reported sleep disturbance at baseline. Baseline sleep disturbance was associated with depressive symptoms (p < .0001), anxiety symptoms (p < .0001), craving (p < .0001), propensity to drink when experiencing unpleasant emotions (p < .0001), physical discomfort (p < .0001), loss of personal control (p = 0.03), conflict (p = 0.002), number of drinks consumed (p = 0.004), drinking days (p = 0.004) and hazardous drinking days (p = 0.03) in bivariate analyses. However, in the multivariable model, only PHQ-9 total score and IDTS physical discomfort subscale were associated with sleep disturbance.

CONCLUSION

Sleep disruption is common in early alcohol recovery. Future studies should examine the prognostic and clinical implications of its association with current depressive symptoms and a propensity to drink while experiencing physical discomfort.

On the path towards personalized medicine: Implications of pharmacogenetic studies of alcohol use disorder medications

Introduction

The heritability of alcohol use disorder (AUD) is estimated to be ~50%; however, the genetic basis of the disease is still poorly understood. The genetic variants identified thus far only explain a small percentage of AUD phenotypic variability. While genome-wide association studies (GWAS) are impacted by technical and methodological limitations, genetic variants that have been identified independently of GWAS findings can moderate the efficacy of AUD medications.

Areas Covered

This review discusses findings from clinical pharmacogenetic studies of AUD medications. While the pharmacogenetic studies reviewed involve several genetic variants in the major neurotransmitter systems, genetic loci in the opioid system have garnered the most attention.

Expert Opinion

The clinical utility of pharmacogenetics in AUD populations is uncertain at this time. There are several ongoing prospective clinical trials that will enhance knowledge regarding the applicability of pharmacogenetics in clinical populations. We recommend that future work in this area consider reverse translating from genotype to phenotype, mapping genes to stages of the addiction cycle, mapping genes to neural circuits, and harnessing large population-based cohorts.

Impact of Sex and ADHD Status on Psychiatric Comorbidity in Treatment-Seeking Alcoholics

Objective: To assess for intrasex and intersex differences in psychiatric comorbidity according to ADHD status in treatment-seeking adults with alcohol use disorders (AUDs). Method: This study was a secondary analysis of data utilizing descriptive statistics from 472 treatment-seeking alcoholics who completed the Psychiatric Research Interview for Substance and Mental Disorders (PRISM). Results: The prevalence of ADHD in males and females was 6.0% and 6.4%, respectively. Males with ADHD and AUDs had higher rates of current and lifetime drug use disorders, current depressive disorders, and current and lifetime anxiety disorders than male alcoholics without ADHD. No intrasex differences in psychiatric comorbidities were identified in female alcoholics with respect to ADHD status. Males with ADHD and AUDs were more likely to have had opioid dependence than ADHD-positive females. No other intersex differences were found. Conclusion: Positive ADHD status was associated with increased psychiatric comorbidity among treatment-seeking alcoholic men.

The Clinical Utility of ASRS-v1.1 for Identifying ADHD in Alcoholics Using PRISM as the Reference Standard

Objective: The objective was to assess the clinical utility of the Adult ADHD Self-Report Scale (ASRS-v1.1) in identifying ADHD in alcoholics using the Psychiatric Research Interview for Substance and Mental Disorders (PRISM) as the diagnostic "gold standard." Method: We performed a secondary analysis of data from 379 treatment-seeking alcoholics who completed the ASRS-v1.1 and the ADHD module of the PRISM. Data analysis included descriptive statistics. Results: The prevalence of ADHD was 7.7% (95% CI = [5.4, 10.8]). The positive predictive value (PPV) of the ASRS-v1.1 was 18.1% (95% CI = [12.4, 25.7]) and the negative predictive value (NPV) was 97.6% (95% CI = [94.9, 98.9]). The ASRS-v1.1 demonstrated a sensitivity of 79.3% (95% CI = [61.6, 90.2]) and a specificity of 70.3% (95% CI = [65.3, 74.8]). Conclusion: The ASRS-v1.1 demonstrated acceptable sensitivity and specificity in a sample of treatment-seeking alcoholics when compared with the PRISM as the reference standard for ADHD diagnosis.

Pharmacogenetics of alcohol addiction: current perspectives

Genetics of alcohol addiction is currently a contradictive and complex field, where data in the most studies reflect methods’ limitations rather than meaningful and complementary results. In our review, we focus on the genetics of alcohol addiction, leaving genetics of acute alcohol intoxication out of the scope. A review of the literature on pharmacogenetic biomarkers development for the pharmacotherapy personalization reveals that today the evidence base concerning these biomarkers is still insufficient. In particular, now the researches with the design of randomized controlled trials and meta-analysis investigating the effect of the SNPs as biomarkers on the therapy efficacy are available for naltrexone only. For other medications, there are only a few studies in small samples. It decreases the possibilities to implement the pharmacogenetic algorithms for the pharmacotherapy personalization in patients with alcohol use disorders (AUD). In view of the importance of the precision approaches development not in addiction medicine only, but in other fields of medicine also to increase the efficacy and safety of the therapy, studies on pharmacogenetic biomarkers development for the medications used in patients with AUD (eg, naltrexone, disulfiram, nalmefene, acamprosate, etc.) remain relevant to this day.

Pharmacogenetics of alcohol use disorder treatments: an update

Introduction: Alcohol use disorder (AUD) is highly prevalent; costly economically, socially, and interpersonally; and grossly undertreated. The low rate of utilization of medications with demonstrated (albeit modest) efficacy is particularly noteworthy. One approach to increasing the utility and safety of available medications is to use a precision medicine approach, which seeks to identify patients for whom specific medications are likely to be most efficacious and have the fewest adverse effects. Areas Covered: We review the literature on the pharmacogenetics of AUD treatment using both approved and off-label medications. We cover both laboratory studies and clinical trials, highlighting valuable mechanistic insights and underscoring the potential value of precision-based care for AUD. Expert Opinion: Pharmacotherapy can be a useful component of AUD treatment. Currently, the evidence regarding genetic predictors of medication efficacy is very limited. Thus, a precision medicine approach is not yet ready for widespread clinical implementation. Further research is needed to identify candidate genetic variants that moderate the response to both established and novel medications. The growing availability of large-scale, longitudinal datasets that enable the synthesis of genetic and electronic health record data provides important opportunities to develop this area of research.

The Genetic Relationship Between Alcohol Consumption and Aspects of Problem Drinking in an Ascertained Sample

BACKGROUND

Genomewide association studies (GWAS) have begun to identify loci related to alcohol consumption, but little is known about whether this genetic propensity overlaps with specific indices of problem drinking in ascertained samples.

METHODS

In 6,731 European Americans who had been exposed to alcohol, we examined whether polygenic risk scores (PRS) from a GWAS of weekly alcohol consumption in the UK Biobank predicted variance in 6 alcohol-related phenotypes: alcohol use, maximum drinks within 24 hours (MAXD), total score on the Self-Rating of the Effects of Ethanol Questionnaire (SRE-T), DSM-IV alcohol dependence (DSM4AD), DSM-5 alcohol use disorder symptom counts (DSM5AUDSX), and reduction/cessation of problematic drinking. We also examined the extent to which an single nucleotide polymorphism (rs1229984) in ADH1B, which is strongly associated with both alcohol consumption and dependence, contributed to the polygenic association with these phenotypes and whether PRS interacted with sex, age, or family history of alcoholism to predict alcohol-related outcomes. We performed mixed-effect regression analyses, with family membership and recruitment site included as random effects, as well as survival modeling of age of onset of DSM4AD.

RESULTS

PRS for alcohol consumption significantly predicted variance in 5 of the 6 outcomes: alcohol use (Δmarginal R2  = 1.39%, Δ area under the curve [AUC] = 0.011), DSM4AD (Δmarginal R2  = 0.56%; ΔAUC = 0.003), DSM5AUDSX (Δmarginal R2  = 0.49%), MAXD (Δmarginal R2  = 0.31%), and SRE-T (Δmarginal R2  = 0.22%). PRS were also associated with onset of DSM4AD (hazard ratio = 1.11, p = 2.08e-5). The inclusion of rs1229984 attenuated the effects of the alcohol consumption PRS, particularly for DSM4AD and DSM5AUDSX, but the PRS continued to exert an independent effect for all 5 alcohol measures (Δmarginal R2 after controlling for ADH1B = 0.14 to 1.22%). Interactions between PRS and sex, age, or family history were nonsignificant.

CONCLUSIONS

Genetic propensity for typical alcohol consumption was associated with alcohol use and was also associated with 4 of the additional 5 outcomes, though the variance explained in this sample was modest. Future GWAS that focus on the multifaceted nature of AUD, which goes beyond consumption, might reveal additional information regarding the polygenic underpinnings of problem drinking.

Sex-specific association of depressive disorder and transient emotional states with alcohol consumption in male and female alcoholics

BACKGROUND

We assessed the impact of comorbid depression and anxiety disorders as well as positive and negative emotional states on alcohol consumption in alcohol dependent men and women.

METHODS

Per day alcohol consumption during 90 days before enrolment was assessed by the Time Line Follow Back (TLFB) in 287 men and 156 women meeting DSM-IV-TR criteria for alcohol dependence. Propensity to drink in negative/positive emotional states was assessed using the Inventory of Drug Taking Situations (IDTS). Psychiatric comorbidities, including major depressive disorder (MDD), substance-induced depression (SID), anxiety disorders (AnxD), or substance-induced anxiety (SIA) were identified by Psychiatric Research Interview of Substance and Mood Disorders (PRISM).

RESULTS

In the combined group, increased number of drinks per day and number of heavy drinking days correlated with increased IDTS scores (all p < 0.0001), while the lifetime history of MDD was associated with fewer drinking days (p = 0.045) but not average number of drinks per day. Male sex was associated with higher alcohol consumption per day (p < 0.0001), but not with the number of drinking days (p > 0.05). Lifetime MDD history was associated with less drinking days (p = 0.0084) and less heavy drinking days (p = 0.021) in alcohol dependent men, while current MDD was associated with higher alcohol use per day in alcohol dependent women (p = 0.044).

CONCLUSIONS

Our findings suggest that emotional states and lifetime MDD history have sex-specific impact on alcohol use in alcohol dependent men and women. The mechanisms underlying these findings and their relevance to treatment outcomes need to be examined in future studies.

Investigational drug therapies in phase I and phase II clinical trials for alcohol use disorders

INTRODUCTION

Alcohol use disorder (AUD) is a complex psychiatric condition characterized by craving, compulsive seeking, loss of control of alcohol consumption as well as the emergence of negative emotional states during withdrawal. Despite the large socioeconomic burden of AUD, therapeutic treatment options lag behind.

AREAS COVERED

This review covers pharmacotherapies currently in phase I/II clinical trials for the treatment of AUDs listed on clinicaltrials.gov. We discuss drug therapies that modulate monoamine, GABA/Glutamate, neuropeptide and neuroimmune systems. We examine in depth preclinical and clinical evidence of a select range of these compounds and consider their utility in treating AUDs.

EXPERT OPINION

Current therapeutic options to treat AUD are inadequate at a population level. Currently there are 30 different compounds and one compound combination in phase I/II clinical trials for AUD. These compounds target various aspects of neurotransmitter signaling, neuroimmune modulation, and alcohol metabolism. Almost 75% of these compounds under trial are Food and Drug Administration (FDA) approved for other indications, which may save time and costs in treatment development. Further, development of therapeutics focused on genetic biomarkers and behavioral screening may improve how treatment decisions are made in the future on a case-by-case basis.

New steps for treating alcohol use disorder

Alcohol use disorder is a complex syndrome with multiple treatment points including drug-induced pathology, withdrawal management, behavioral/cognitive strategies, and relapse prevention. These different components may be complicated by genotype and phenotype. A huge milestone for the treatment of alcohol use disorder across several countries in the last 10 years was the introduction of practice guidelines integrating clinical expertise and research evidence. These provide a summary of interventions that have been shown to be effective following rigorous and replicated clinical trials. Inspection of these guidelines reveals good consistency, but little evidence of progress in treatment approaches for alcohol use disorder over the past decade. In this mini-review, we discuss emerging treatments for alcohol use disorder that may supplement or improve the evidence-based treatments that are currently recommended. New medications, the emergence of digital technology, and other novel approaches such as transcranial magnetic stimulation are all discussed with reference to treatments already in practice. We also consider how individual differences in genotype and phenotype may affect outcomes. Together with improvements in technology, this knowledge offers a powerful tool for designing personalized approaches to treatment, and hence improving prognosis for rehabilitation programs.

Neurogranin in the nucleus accumbens regulates NMDA receptor tolerance and motivation for ethanol seeking

Dysfunction of N-methyl-d-aspartate receptor (NMDAR) signaling in the nucleus accumbens (NAc) has been implicated in the pathophysiology of alcohol use disorders (AUD). Neurogranin (Ng), a calmodulin-binding protein, is exclusively expressed in the post-synapse, and mediates NMDAR driven synaptic plasticity by regulating the calcium-calmodulin (Ca²⁺-CaM) pathway. To study the functional role of Ng in AUD, we administrated behavior tests including Pavlovian instrument transfer (PIT), operant conditioning, and rotarod test using Ng null mice (Ng^-/- mice). We used adeno-associated virus (AAV)-mediated Ng expression and pharmacological manipulation to validate behavioral responses in Ng^-/- mice. The results from our multidisciplinary approaches demonstrated that deficit of Ng increases tolerance to NMDAR inhibition and elicit faster cue reactivity during PIT without changes in ethanol reward. Operant conditioning results demonstrated that Ng^-/- mice self-administered significantly more ethanol and displayed reduced sensitivity to aversive motivation. We identified that ethanol exposure decreases mGluR5 (metabotropic glutamate receptor 5) expression in the NAc of Ng^-/- mice and pharmacological inhibition of mGluR5 reverses NMDAR desensitization in Ng^-/- mice. Together these findings specifically suggest that accumbal Ng plays an essential role in the counterbalance between NMDAR and mGluR5 signaling; which alters NMDAR resistance, and thereby altering aversive motivation for ethanol and may ultimately contribute to susceptibility for alcohol addiction.

Pharmacogenomics in Psychiatric Practice

Pharmacogenomic testing in psychiatry is becoming an established clinical procedure. Several vendors provide clinical interpretation of combinatorial pharmacogenomic testing of gene variants that have documented predictive implications regarding either pharmacologic response or adverse effects in depression and other psychiatric conditions. Such gene profiles have demonstrated improvements in outcome in depression, and reduction of cost of care of patients with inadequate clinical response. Additionally, several new gene variants are being studied to predict specific response in individuals. Many of these genes have demonstrated a role in the pathophysiology of depression or specific depressive symptoms. This article reviews the current state-of-the-art application of psychiatric pharmacogenomics.

Metabolomics biomarkers to predict acamprosate treatment response in alcohol-dependent subjects

Precision medicine for alcohol use disorder (AUD) allows optimal treatment of the right patient with the right drug at the right time. Here, we generated multivariable models incorporating clinical information and serum metabolite levels to predict acamprosate treatment response. The sample of 120 patients was randomly split into a training set (n = 80) and test set (n = 40) five independent times. Treatment response was defined as complete abstinence (no alcohol consumption during 3 months of acamprosate treatment) while nonresponse was defined as any alcohol consumption during this period. In each of the five training sets, we built a predictive model using a least absolute shrinkage and section operator (LASSO) penalized selection method and then evaluated the predictive performance of each model in the corresponding test set. The models predicted acamprosate treatment response with a mean sensitivity and specificity in the test sets of 0.83 and 0.31, respectively, suggesting our model performed well at predicting responders, but not non-responders (i.e. many non-responders were predicted to respond). Studies with larger sample sizes and additional biomarkers will expand the clinical utility of predictive algorithms for pharmaceutical response in AUD.

Review article: pharmacotherapy for alcohol dependence - the why, the what and the wherefore

BACKGROUND

The development of alcohol dependence is associated with significant morbidity and mortality. For the majority of affected people the most appropriate goal, in terms of drinking behaviour, is abstinence from alcohol. Psychosocial intervention is the mainstay of the treatment but adjuvant pharmacotherapy is also available and its use recommended.

AIM

To provide an updated analysis of current and potential pharmacotherapeutic options for the management of alcohol dependence. In addition, factors predictive of therapeutic outcome, including compliance and pharmacogenetics, and the current barriers to treatment, including doctors' unwillingness to prescribe these agents, will be explored.

METHODS

Relevant papers were selected for review following extensive, language- and date-unrestricted, electronic and manual searches of the literature.

RESULTS

Acamprosate and naltrexone have a substantial evidence base for overall efficacy, safety and cost-effectiveness while the risks associated with the use of disulfiram are well-known and can be minimised with appropriate patient selection and supervision. Acamprosate can be used safely in patients with liver disease and in those with comorbid mental health issues and co-occurring drug-related problems. A number of other agents are being investigated for potential use for this indication including: baclofen, topiramate and metadoxine.

CONCLUSION

Pharmacotherapy for alcohol dependence has been shown to be moderately efficacious with few safety concerns, but it is substantially underutilised. Concerted efforts must be made to remove the barriers to treatment in order to optimise the management of people with this condition.

Strain-Dependent Effects of Acute Alcohol on Synaptic Vesicle Recycling and Post-Tetanic Potentiation in Medial Glutamate Inputs to the Mouse Basolateral Amygdala

BACKGROUND

Inbred mouse strains are differentially sensitive to the acute effects of ethanol (EtOH) and are useful tools for examining how unique genomes differentially affect alcohol-related behaviors and physiology. DBA/2J mice have been shown to be sensitive to the acute anxiolytic effects of alcohol as well as the anxiogenic effects of withdrawal from chronic alcohol exposure, while B6 mice are resistant to both. Considering that the basolateral amygdala (BLA) is an important brain region for the acute and chronic effects of EtOH on fear and anxiety related behaviors, we hypothesized that there would be strain-dependent differences in the acute effects of EtOH in BLA slices.

METHODS

We utilized patch clamp electrophysiology in BLA coronal slices from 4 inbred mouse strains (A/J, BALBcJ, C57BL/6J, and DBA/2J) to examine how genetic background influences acute EtOH effects on synaptic vesicle recycling and post-tetanic potentiation (PTP) in response to low (2 Hz)- and high (40 Hz)-frequency stimulation.

RESULTS

We found that EtOH inhibited synaptic vesicle recycling in a strain- and stimulation frequency-dependent manner. Vesicle recycling in DBA/2J and BALBcJ cells was inhibited by acute EtOH during both low- and high-frequency stimulation, while recycling measured from A/J cells was sensitive only during high-frequency stimulation. Recycling at C57BL/6J synapses was insensitive to EtOH regardless of stimulation frequency. We additionally found that cells from DBA/2J and BALBcJ mice were sensitive to EtOH-mediated inhibition of PTP.

CONCLUSIONS

Acute EtOH application inhibited vesicle recycling and PTP at glutamatergic synapses in both a strain- and frequency-dependent fashion. Several presynaptic proteins that contribute to synaptic vesicle priming in addition to PTP have been implicated in alcohol-related behaviors, including Munc13, Munc18, and RIM proteins, making them potential candidates for the molecular mechanism controlling these effects.

Anterior Cingulate Glutamate Is Reduced by Acamprosate Treatment in Patients With Alcohol Dependence

Although the precise drug mechanism of action of acamprosate remains unclear, its antidipsotropic effect is mediated in part through glutamatergic neurotransmission. We evaluated the effect of 4 weeks of acamprosate treatment in a cohort of 13 subjects with alcohol dependence (confirmed by a structured interview, Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision) on proton magnetic resonance spectroscopy glutamate levels in the midline anterior cingulate cortex (MACC). We compared levels of metabolites with a group of 16 healthy controls. The Pennsylvania Alcohol Craving Scale was used to assess craving intensity. At baseline, before treatment, the mean cerebrospinal fluid-corrected MACC glutamate (Glu) level was significantly elevated in subjects with alcohol dependence compared with controls (P = 0.004). Four weeks of acamprosate treatment reduced glutamate levels (P = 0.025), an effect that was not observed in subjects who did not take acamprosate. At baseline, there was a significant positive correlation between cravings, measured by the Pennsylvania Alcohol Craving Scale, and MACC (Glu) levels (P = 0.019). Overall, these data would suggest a normalizing effect of acamprosate on a hyperglutamatergic state observed in recently withdrawn patients with alcohol dependence and a positive association between MACC glutamate levels and craving intensity in early abstinence. Further research is needed to evaluate the use of these findings for clinical practice, including monitoring of craving intensity and individualized selection of treatment with antidipsotropic medications in subjects with alcohol dependence.

Gender-specific effects of comorbid depression and anxiety on the propensity to drink in negative emotional states

BACKGROUND AND AIMS

Depression and anxiety are often comorbid with alcoholism and contribute to craving and relapse. We aimed to estimate the prevalence of life-time diagnoses of major depressive disorder (MDD), substance-induced depression (SID), anxiety disorder (AnxD) and substance-induced anxiety (SIA), the effects of these comorbidities on the propensity to drink in negative emotional states (negative craving), and test whether these effects differ by sex.

DESIGN

Secondary analyses of baseline data collected in a single-arm study of pharmacogenetic predictors of acamprosate response.

SETTING

Academic medical center and affiliated community-based treatment programs in the American upper mid-west.

PARTICIPANTS

A total of 287 males and 156 females aged 18-80 years, meeting DSM-IV criteria for alcohol dependence.

MEASUREMENTS

The primary outcome measure was 'propensity to drink in negative emotional situations' (determined by the Inventory of Drug Taking Situations) and the key predictors/covariates were sex and psychiatric comorbidities, including MDD, SID, AnxD and SIA (determined by Psychiatric Research Interview of Substance and Mood Disorders).

FINDINGS

The prevalence of the MDD, SID and AnxD was higher in females compared with males (33.1 versus 18.4%, 44.8 versus 26.4% and 42.2 versus 27.4%, respectively; P < 0.01, each), while SIA was rare (3.3%) and did not differ by sex. Increased propensity to drink in negative emotional situations was associated with comorbid MDD (β = 6.6, P = 0.013) and AnxD (β = 4.8, P = 0.042) as well as a SID × sex interaction effect (P = 0.003), indicating that the association of SID with propensity to drink in negative emotional situations differs by sex and is stronger in males (β = 7.9, P = 0.009) compared with females (β = -6.6, P = 0.091).

CONCLUSIONS

There appears to be a higher prevalence of comorbid depression and anxiety disorders as well as propensity to drink in negative emotional situations in female compared with male alcoholics. Substance-induced depression appears to have a sex-specific effect on the increased risk for drinking in negative emotional situations in males.

Elevated Glutamate Levels in the Left Dorsolateral Prefrontal Cortex Are Associated with Higher Cravings for Alcohol

BACKGROUND

Quantifying craving longitudinally during the course of withdrawal, early abstinence, and relapse is essential for optimal management of alcohol use disorder (AUD). In an effort to identify biological correlates of craving, we used proton magnetic resonance spectroscopy (1H-MRS) to investigate the correlation between craving and glutamate levels in the left dorsolateral prefrontal cortex (LDLPFC) of patients with AUD.

METHODS

Participants underwent 1H-MRS of the LDLPFC with 2-dimensional J-resolved (2DJ) averaged PRESS. MRS data were processed with LCModel and cerebrospinal fluid (CSF)-corrected to generate metabolite concentrations. The Penn Alcohol Craving Scale (PACS) and the 30-day time line follow-back (TLFB 30) were used to quantify craving for alcohol and drinking patterns, respectively.

RESULTS

There was a statistically significant positive correlation between CSF-corrected glutamate ([Glu]) levels and PACS scores (n = 14; p = 0.005). When PACS scores were dichotomized (< or ≥median = 16), [Glu] levels were significantly higher in the high- versus low-craving group (p = 0.007). In addition, there was a significant negative correlation between CSF-corrected N-acetyl aspartic acid ([NAA]) levels and mean number of drinks per drinking day in the past month (n = 13; TLFB 30; p = 0.012). When mean TLFB 30 was dichotomized (< or ≥median = 7.86), [NAA] levels were significantly lower in subjects that consumed more alcoholic beverages. There was no significant correlation between [Glu] and [NAA] levels with other measures of drinking behavior and or depression symptom severity.

CONCLUSIONS

While limited by small sample size, these data suggest that glutamate levels in LDLPFC are associated with alcohol craving intensity in patients with AUD. Further study with larger sample size is needed to replicate this finding and evaluate the merits of glutamate spectroscopy as a biological correlate of alcohol craving intensity and a guide to treatment interventions.

Discovery, Development, and Adoption of Medications to Treat Alcohol Use Disorder: Goals for the Phases of Medications Development

For more than 25 years, advances have been made in developing medications to treat alcohol use disorder (AUD), highlighted by the U.S. Food and Drug Administration's approval of naltrexone (oral and long-acting) and acamprosate. Despite this progress, more work remains to be done in this area because these medications, although effective for some people, do not work for everyone. A high priority for the National Institute on Alcohol Abuse and Alcohol is to put into place a solid infrastructure to aid in the development of medications that are more effective than those currently available and with few side effects. Medication development, especially for a disorder as complex as AUD, is challenging and involves multiple phases, including discovery of "druggable" targets, preclinical studies, human clinical trials, and the adoption and implementation of the new medication into mainstream medicine. A successful medications development program requires clearly established goals for each phase to ensure that a candidate compound is not trapped in one particular phase, a condition known as "the valley of death." In this article, the phases of medication development are described as they apply to AUD, and specific goals of each phase are identified for the next decade. In addition, several important crosscutting themes are outlined for each phase, all of which are essential for advancing medications development. These include identifying and validating screening models and druggable targets, making use of precision medicine, and establishing partnerships among key stakeholders. Our goal in writing this article is to provide a guide on medications development that will aid the alcohol research community in planning, testing, and developing medications for AUD.

Pharmacogenetics of alcohol use disorders and comorbid psychiatric disorders

Alcohol use disorders (AUDs) represent a significant health burden worldwide. Currently, there are three medications approved by the U.S. Food and Drug Administration for the treatment of AUDs, and other drugs are being prescribed off-label for this purpose. However, response rates for pharmacologic treatment are low, and extant research suggests that treatment effects may partially depend on genetic factors. Personalized medicine, or using a patient's genetics and/or personal history to determine efficacy of treatment prior to prescription, is an emerging tool that will help clinicians treat their patients more effectively and safely. This review systematically discusses current findings from AUD pharmacotherapy trials examining disulfiram, acamprosate, naltrexone, the injectable naltrexone, and topiramate. Furthermore, it presents pharmacogenetics findings associated with these medications in an attempt to further the field of personalized medicine. Research from trials examining AUDs and comorbid major depressive disorder and anxiety disorders is also presented, and pharmacogenetic findings for these treatments are discussed. Lastly, the authors comment on the present and future states of the field of personalized medicine for AUD.

Precision in Addiction Care: Does It Make a Difference?

This perspective article explores the possibilities of precision in addiction care -- even better individually fitted or tailor-made care -- and examines what changes we need to make in order to realize sensible progress in epidemiological key figures. The first part gives a short review on the development of addiction care and tries to answer the question of where we stand now and what has been achieved in addiction science through the development and evaluation of interventions in the past decades. Following this analysis, attention will be paid to what lies ahead. This second part focuses on the question of how addiction care can deal with the consequences of the emerging paradigm of personalized or precision medicine, which is based on the fundamental assumption that individual differences matter. Finally, some limitations and conditions as well as tasks and goals for progress are raised. In conclusion, it is argued that integration of addiction care in (mental) health care in the future is desirable.

Global research challenges and opportunities for mental health and substance-use disorders

The research agenda for global mental health and substance-use disorders has been largely driven by the exigencies of high health burdens and associated unmet needs in low- and middle-income countries. Implementation research focused on context-driven adaptation and innovation in service delivery has begun to yield promising results that are improving the quality of, and access to, care in low-resource settings. Importantly, these efforts have also resulted in the development and augmentation of local, in-country research capacities. Given the complex interplay between mental health and substance-use disorders, medical conditions, and biological and social vulnerabilities, a revitalized research agenda must encompass both local variation and global commonalities in the impact of adversities, multi-morbidities and their consequences across the life course. We recommend priorities for research - as well as guiding principles for context-driven, intersectoral, integrative approaches - that will advance knowledge and answer the most pressing local and global mental health questions and needs, while also promoting a health equity agenda and extending the quality, reach and impact of scientific enquiry.

An analysis of moderators in the COMBINE study: Identifying subgroups of patients who benefit from acamprosate

The goal of the current study was to use tree-based methods to identify moderators of acamprosate effect on abstinence from heavy drinking in COMBINE, the largest study of pharmacotherapy for alcoholism in the United States to date. We used three different tree-based methods for identification of subgroups with enhanced treatment response on acamprosate based on over 100 predictors measured at baseline in COMBINE. No heavy drinking during the last two months of treatment was the considered outcome. All three methods identified consecutive days of abstinence prior to treatment as the most important moderator of treatment effect. Acamprosate was beneficial for participants with shorter abstinence (1 week or less) especially when body mass index was low or normal. In this group, 46% of participants receiving active acamprosate abstained from heavy drinking compared to 23% of those receiving placebo acamprosate. Prior treatment, age, drinking goal and cognitive inefficiency were identified as moderators of acamprosate effects by one of the three methods. In conclusion, acamprosate may be beneficial for participants with shorter abstinence who are not overweight or obese. One hypothesis for this finding is that this subgroup may have greater glutamatergic hyperactivity, a target of acamprosate, and may achieve better drug plasma levels based on their lower BMI. In contrast, those with extended pretreatment abstinence who have an otherwise good prognosis did not benefit from acamprosate. Further validation of the results in independent data sets is necessary.

Alcohol and violence: neuropeptidergic modulation of monoamine systems

Neurobiological processes underlying the epidemiologically established link between alcohol and several types of social, aggressive, and violent behavior remain poorly understood. Acute low doses of alcohol, as well as withdrawal from long-term alcohol use, may lead to escalated aggressive behavior in a subset of individuals. An urgent task will be to disentangle the host of interacting genetic and environmental risk factors in individuals who are predisposed to engage in escalated aggressive behavior. The modulation of 5-hydroxytryptamine impulse flow by gamma-aminobutyric acid (GABA) and glutamate, acting via distinct ionotropic and metabotropic receptor subtypes in the dorsal raphe nucleus during alcohol consumption, is of critical significance in the suppression and escalation of aggressive behavior. In anticipation and reaction to aggressive behavior, neuropeptides such as corticotropin-releasing factor, neuropeptide Y, opioid peptides, and vasopressin interact with monoamines, GABA, and glutamate to attenuate and amplify aggressive behavior in alcohol-consuming individuals. These neuromodulators represent novel molecular targets for intervention that await clinical validation. Intermittent episodes of brief social defeat during aggressive confrontations are sufficient to cause long-lasting neuroadaptations that can lead to the escalation of alcohol consumption.

Elevated baseline serum glutamate as a pharmacometabolomic biomarker for acamprosate treatment outcome in alcohol-dependent subjects

Acamprosate has been widely used since the Food and Drug Administration approved the medication for treatment of alcohol use disorders (AUDs) in 2004. Although the detailed molecular mechanism of acamprosate remains unclear, it has been largely known that acamprosate inhibits glutamate action in the brain. However, AUD is a complex and heterogeneous disorder. Thus, biomarkers are required to prescribe this medication to patients who will have the highest likelihood of responding positively. To identify pharmacometabolomic biomarkers of acamprosate response, we utilized serum samples from 120 alcohol-dependent subjects, including 71 responders (maintained continuous abstinence) and 49 non-responders (any alcohol use) during 12 weeks of acamprosate treatment. Notably, baseline serum glutamate levels were significantly higher in responders compared with non-responders. Importantly, serum glutamate levels of responders are normalized after acamprosate treatment, whereas there was no significant glutamate change in non-responders. Subsequent functional studies in animal models revealed that, in the absence of alcohol, acamprosate activates glutamine synthetase, which synthesizes glutamine from glutamate and ammonia. These results suggest that acamprosate reduces serum glutamate levels for those who have elevated baseline serum glutamate levels among responders. Taken together, our findings demonstrate that elevated baseline serum glutamate levels are a potential biomarker associated with positive acamprosate response, which is an important step towards development of a personalized approach to treatment for AUD.

Pharmacotherapy for alcohol dependence: A stratified approach

Alcohol dependence is a common disorder in many societies worldwide, and remains difficult to identify and treat. It is also a risk factor for many secondary non-communicable diseases. Pharmacotherapy is one available treatment option, but appears to be underutilised in practice. Major barriers to use of medications in this area include lack of clinical guidance and questionable efficacy. However, for each medication there appears to be a subpopulation that responds positively, and understanding the moderating factors to treatment efficacy is an important research goal. Thus, this review provides a narrative regarding potential stratification techniques in pharmacological treatment of alcohol dependence, with a specific focus on typologies and pharmacogenetics. In addition, we discuss the basic background of stratified medicine and recent studies on genetic predisposition to alcohol dependence. A growing repository of data exists for both approved and non-approved pharmacotherapies, but failure to replicate findings, inadequate sample sizes, and insufficient funding has resulted in a translational gap. Implementing evidence-based stratified/personalised therapy and identifying new therapeutic agents may lead to improved clinical outcomes and reduced financial burden. Despite some promising findings to date, much work is still required.

The pharmacogenetics of alcohol use disorder

BACKGROUND

Annually, the use and abuse of alcohol contributes to millions of deaths and billions of dollars in societal costs. To determine the impact of genetic variation on the susceptibility to the disorder and its response to treatment, studies have been conducted to assess the contribution of a variety of candidate genetic variants. These variants, which we review here, were chosen based upon their observed or hypothesized functional relevance to alcohol use disorder (AUD) risk or to the mechanism by which medications used to treat the disorder exert their effects.

METHODS

This qualitative review examines studies in which candidate polymorphisms were tested as moderator variables to identify pharmacogenetic effects on either the subjective response to alcohol or the outcomes of pharmacotherapy.

RESULTS

Although findings from these studies provide evidence of a number of clinically relevant pharmacogenetic effects, the literature is limited and there are conflicting findings that require resolution.

CONCLUSIONS

Pharmacogenetic studies of AUD treatment that use greater methodological rigor and better statistical controls, such as corrections for multiple testing, may help to resolve inconsistent findings. These procedures could also lead to the discovery of more robust and clinically meaningful moderator effects. As the field evolves through methodological standardization and the use of larger study samples, pharmacogenetic research has the potential to inform clinical care by enhancing therapeutic effects and personalizing treatments. These efforts may also provide insights into the mechanisms by which medications reduce heavy drinking or promote abstinence in patients with an AUD.