Determination of genotype combinations that can predict the outcome of the treatment of alcohol dependence using the 5-HT(3) antagonist ondansetron

The Link Between Alcohol Consumption and Kidney Injury

Alcohol consumption contributes to systemic organ dysfunction, but its direct effect on kidney health is unclear. Epidemiological studies show inconsistent findings due to reliance on conventional markers like serum creatinine (sCr) and blood urea nitrogen (BUN), which are insensitive to early chronic kidney disease (CKD) and influenced by factors such as muscle mass, diet, and hydration status. Experimental studies indicate that alcohol may directly exacerbate renal damage through mitochondrial dysfunction, oxidative stress, and inflammation. Furthermore, indirect effects from alcohol-induced altered intestinal permeability and microbiome, liver injury, microcirculatory/cardiac dysfunction and muscle damage may also facilitate kidney damage. Notably, alcohol-related liver disease can lead to hepatorenal syndrome, a severe form of kidney dysfunction driven by circulatory disturbances and systemic inflammation. This overview explores the adverse effects of alcohol misuse on kidney health and disease, emphasizing the need for comprehensive epidemiological studies with more sensitive kidney injury biomarkers. It also highlights the importance of using clinically relevant preclinical models to clarify the underlying mechanisms of alcohol-related kidney injury and to enhance our understanding of its long-term clinical consequences.

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.

The role of brain serotonin signaling in excessive alcohol consumption and withdrawal: A call for more research in females

Alcohol Use Disorder (AUD) is a leading cause of death and disability worldwide, but current treatments are insufficient in fully addressing the symptoms that often lead to relapses in alcohol consumption. The brain's serotonin system has been implicated in AUD for decades and is a major regulator of stress-related behaviors associated with increased alcohol consumption. This review will discuss the current literature on the association between neurobiological adaptations in serotonin systems and AUD in humans as well as the effectiveness of serotonin receptor manipulations on alcohol-related behaviors like consumption and withdrawal. We will further discuss how these findings in humans relate to findings in animal models, including a comparison of systemic pharmacological manipulations modulating alcohol consumption. We next provide a detailed overview of brain region-specific roles for serotonin and serotonin receptor signaling in alcohol-related behaviors in preclinical animal models, highlighting the complexity of forming a cohesive model of serotonin function in AUD and providing possible avenues for more effective therapeutic intervention. Throughout the review, we discuss what is known about sex differences in the sequelae of AUD and the role of serotonin in these sequelae. We stress a critical need for additional studies in women and female animals so that we may build a clearer path to elucidating sex-specific serotonergic mechanisms and develop better treatments.

Alcohol and the dopamine system

The mesolimbic dopamine pathway plays a major role in drug reinforcement and is likely involved also in the development of drug addiction. Ethanol, like most addictive drugs, acutely activates the mesolimbic dopamine system and releases dopamine, and ethanol-associated stimuli also appear to trigger dopamine release. In addition, chronic exposure to ethanol reduces the baseline function of the mesolimbic dopamine system. The molecular mechanisms underlying ethanol´s interaction with this system remain, however, to be unveiled. Here research on the actions of ethanol in the mesolimbic dopamine system, focusing on the involvement of cystein-loop ligand-gated ion channels, opiate receptors, gastric peptides and acetaldehyde is briefly reviewed. In summary, a great complexity as regards ethanol´s mechanism(s) of action along the mesolimbic dopamine system has been revealed. Consequently, several new targets and possibilities for pharmacotherapies for alcohol use disorder have emerged.

Repurposing drugs for treatment of alcohol use disorder

Repurposing drugs for the treatment of alcohol dependence involves the use of drugs that were initially developed for other conditions, but have shown promise in reducing alcohol use or preventing relapse. This approach can offer a more cost-effective and time-efficient alternative to developing new drugs from scratch. Currently approved medications for alcohol use disorder (AUD) include acamprosate, disulfiram, naltrexone, nalmefene, baclofen, and sodium oxybate. Acamprosate was developed specifically for AUD, while disulfiram's alcohol-deterrent effects were discovered incidentally. Naltrexone and nalmefene were originally approved for opioids but found secondary applications in AUD. Baclofen and sodium oxybate were repurposed from neurological conditions. Other drugs show promise. Topiramate and zonisamide, anticonvulsants, demonstrate efficacy in reducing alcohol consumption. Another anticonvulsant, gabapentin has been disappointing overall, except in cases involving alcohol withdrawal symptoms. Varenicline, a nicotinic receptor agonist, benefits individuals with less severe AUD or concurrent nicotine use. Ondansetron, a 5-HT3 antagonist, has potential for early-onset AUD, especially when combined with naltrexone. Antipsychotic drugs like aripiprazole and quetiapine have limited efficacy. Further investigation is needed for potential repurposing of α1 adrenergic receptor antagonists prazosin and doxazosin, glucocorticoid receptor antagonist mifepristone, the phosphodiesterase inhibitor Ibudilast, the cysteine prodrug N-acetylcysteine, and the OX1R and OX2R blocker Suvorexant. This review supports repurposing drugs as an effective strategy for expanding treatment options for AUD.

A critical scientific evaluation of a purportedly negative data report - response to Seneviratne et al. 2022

A core principle in the pursuit of scientific knowledge is that science is self-correcting and that important results should be replicable. Hypotheses need to be reinforced, adjusted, or rejected when novel results are obtained. Replication of results confirms hypotheses and enhances their integration into scientific practice. In contrast, publication of substantiated and replicated negative findings (i.e., non-significant or opposite findings) can be the basis to reject erroneous hypotheses or develop alternative strategies for investigation. Replication is a problem in all research fields. The Psychology Reproductivity Project reported that only 36% of 'highly influential' published research in highly ranked journals were reproduced. Similar to positive data, negative data can be flawed. Errors in a negative data set can be based on methodology, statistics, conceptual defects, and flawed peer review. The peer review process has received progressive scrutiny. A large-scale review of the peer review process of manuscripts submitted to the British Medical Journal group indicated that the process could be characterized as inconsistent, inaccurate, and biased. Further analysis indicated that the peer process is easily manipulated, indicative of a failed system, is a major factor behind the lack of replication in science (acceptance of flawed manuscripts), suppresses opposing scientific evidence and views, and causes gaps in and lack of growth of science. Complicating the integrity of scientific publication is the role of Editors/Researchers. Ethical guidelines exist for major publishing houses about editorial ethics, behavior, and practice.

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.

Off-label and investigational drugs in the treatment of alcohol use disorder: A critical review

Compounds known to be successful in the treatment of alcohol use disorder include the aversive agent, Disulfiram, the glutamatergic NMDA receptor antagonist, Acamprosate, and the opioid receptor antagonists, Naltrexone and Nalmefene. Although all four are effective in maintaining abstinence or reduction of alcohol consumption, only a small percentage of patients receive pharmacological treatment. In addition, many other medications have been investigated for their therapeutic potential in the treatment of alcohol use disorder. In this review we summarize and compare Baclofen, Gabapentin, Topiramate, Ondansetron, Varenicline, Aripiprazole, Quetiapine, Clozapine, Antidepressants, Lithium, Neuropeptide Y, Neuropeptide S, Corticotropin-releasing factor antagonists, Oxytocin, PF-05190457, Memantine, Ifenprodil, Samidorphan, Ondelopran, ABT-436, SSR149415, Mifepristone, Ibudilast, Citicoline, Rimonabant, Surinabant, AM4113 and Gamma-hydroxybutyrate While some have shown promising results in the treatment of alcohol use disorder, others have disappointed and should be excluded from further investigation. Here we discuss the most promising results and highlight medications that deserve further preclinical or clinical study. Effective, patient-tailored treatment will require greater understanding provided by many more preclinical and clinical studies.

A randomized, double-blind, placebo-controlled, pharmacogenetic study of ondansetron for treating alcohol use disorder

BACKGROUND

In a previous study, ondansetron, a serotonin 5-HT3 receptor antagonist, reduced drinking intensity (drinks/drinking day [DPDD]) among European-ancestry (EA) participants with moderate-to-severe alcohol use disorder (AUD) and variants in genes encoding the serotonin transporter (SLC6A4) and 5-HT3A (HTR3A), and 5-HT3B (HTR3B) receptors. We tested whether (1) ondansetron reduces DPDD among individuals of either European or African ancestry (AA), and (2) that reductions in DPDD are greatest among ondansetron-treated individuals with population-specific combinations of genotypes at SLC6A4, HTR3A, and HTR3B.

METHODS

In this 16-week, double-blind, placebo-controlled, parallel-group clinical trial, adults with AUD were randomized to receive low-dose oral ondansetron (0.33 mg twice daily) or placebo stratified by "responsive" versus "nonresponsive" genotype defined using population-specific genotypes at the three genetic loci. Generalized estimating equation regression models and a modified intent-to-treat analysis were used to compare the treatment groups on the primary outcome-DPDD-and two secondary outcomes-heavy drinking days per week [HDD] and drinks per day [DPD] across the 16 weeks of treatment.

RESULTS

Of 296 prospective participants screened, 95 (58 EA and 37 AA) were randomized and received at least one dose of study medication. In the modified intent-to-treat analysis, the ondansetron group averaged 0.40 more DPDD (p = 0.51), 1.35 times as many HDD (p = 0.16), and 1.06 times as many DPD (p = 0.59) as the placebo group. There were no significant interactions with genotype. There were no study-related serious adverse events (AEs) and similar proportions of participants in the two treatment groups experienced AEs across organ systems.

CONCLUSIONS

We found no evidence that low-dose oral ondansetron is beneficial in the treatment of AUD, irrespective of genotype, thus failing to confirm prior study findings. However, the study was underpowered to identify medication by genotype interactions.

The role of alcohol intake in the pharmacogenetics of treatment with clozapine

Clozapine (CLZ) is an atypical antipsychotic reserved for patients with refractory psychosis, but it is associated with a significant risk of severe adverse reactions (ADRs) that are potentiated with the concomitant use of alcohol. Additionally, pharmacogenetic studies have explored the influence of several genetic variants in CYP450, receptors and transporters involved in the interindividual response to CLZ. Herein, we systematically review the current multiomics knowledge behind the interaction between CLZ and alcohol intake, and how its concomitant use might modulate the pharmacogenetics. CYP1A2*1F, *1C and other alleles not yet discovered could support a precision medicine approach for better therapeutic effects and fewer CLZ ADRs. CLZ monitoring systems should be amended and include alcohol intake to protect patients from severe CLZ ADRs.

A pharmacogenomic investigation of the cardiac safety profile of ondansetron in children and pregnant women

BACKGROUND

Ondansetron is a highly effective antiemetic for the treatment of nausea and vomiting. However, this medication has also been associated with QT prolongation. Pharmacogenomic information on therapeutic response to ondansetron exists, but no investigation has been performed on genetic factors that influence the cardiac safety of this medication.

METHODS

Three patient groups receiving ondansetron were recruited and followed prospectively (pediatric post-surgical patients n = 101; pediatric oncology patients n = 98; pregnant women n = 62). Electrocardiograms were conducted at baseline, and 5- and 30-min post-ondansetron administration, to determine the effect of ondansetron treatment on QT interval. Pharmacogenomic associations were assessed via analyses of comprehensive CYP2D6 genotyping and genome-wide association study data.

RESULTS

In the entire cohort, 62 patients (24.1%) met the criteria for prolonged QT, with 1.2% of the cohort exhibiting unsafe QT prolongation. The most significant shift from baseline occurred at five minutes post-ondansetron administration (P = 9.8 × 10^-4). CYP2D6 activity score was not associated with prolonged QT. Genome-wide analyses identified novel associations with a missense variant in TLR3 (rs3775291; P = 2.00 × 10^-7) and a variant linked to the expression of SLC36A1 (rs34124313; P = 1.97 × 10^-7).

CONCLUSIONS

This study has provided insight into the genomic basis of ondansetron-induced cardiac changes and has emphasized the importance of genes that have been implicated in serotonin-related traits. These biologically-relevant findings represent the first step towards understanding this adverse event with the overall goal to improve the safety of this commonly used antiemetic medication.

Background sensitivity to chemotherapy-induced nausea and vomiting and response to antiemetics in paediatric patients: a genetic association study

Chemotherapy-induced nausea and vomiting (CINV) remains a common adverse effect for children with cancer. In children, chemotherapy emetogenicity and patient factors such as susceptibility to motion sickness and age group determine a patient's risk of CINV. Besides known risk factors, genetic factors may play a role in interindividual variation in the occurrence of CINV. We investigated the influence of candidate gene polymorphisms on the efficacy of antiemetics and on the background sensitivity to CINV in children. This prospective study included 100 children with cancer (median age 6.4 years, range 0.8-17.9) who received moderately to highly emetogenic chemotherapy. Participants registered nausea and vomiting episodes in a mobile app. Genotypes were determined by whole-genome sequencing (n = 79) or Sanger sequencing (n = 21) for 71 genetic polymorphisms involved in motion sickness and antiemetic pathways. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to estimate associations between acute CINV and genotypes adjusting for susceptibility to motion sickness and age group. Rs3782025 in the 5-hydroxytryptamine type 3 (5-HT3) receptor gene (HTR3B) [minor allele frequency (MAF): 0.48] affected response to 5-HT3 receptor antagonists; acute CINV occurred in 76% of patients with GA/AA genotypes and in 41% of patients with GG genotype (OR 5.59; 95% CI 1.74-17.9, dominant genetic model). Rs2975226 in the dopamine transporter gene (SLC6A3) (MAF: 0.54) was associated with acute CINV (OR 5.79; 95% CI 1.09-30.67, recessive genetic model). Polymorphisms in HTR3B and SLC6A3 may contribute to the variability in response to antiemetic prophylaxis for CINV in children.

An inpatient human laboratory study assessing the safety and tolerability, pharmacokinetics, and biobehavioral effect of GET 73 when co-administered with alcohol in individuals with alcohol use disorder

RATIONALE

Previous work suggests that GET 73, a novel compound with putative activity on the metabotropic glutamate receptor subtype 5 (mGluR5), may represent a novel pharmacological treatment for alcohol use disorder (AUD).

OBJECTIVE

In this study, we investigated the safety, tolerability, pharmacokinetics, and biobehavioral effects of GET 73, when co-administered with alcohol, in individuals with alcohol dependence (AD).

METHODS

This was an inpatient, cross-over, randomized, double-blind, placebo-controlled, human laboratory study with non-treatment-seeking, alcohol-dependent individuals. The study used a within-subject design, with two counterbalanced stages, during which participants received GET 73 and then placebo, or vice versa. During each stage, participants underwent an alcohol interaction session and, on a separate day, an alcohol cue reactivity, followed by an alcohol self-administration session.

RESULTS

Safety outcomes of GET 73 were excellent with no serious adverse events, nor adverse events of severe grade. The co-administration of alcohol and GET 73 did not affect the pharmacokinetics of GET 73 or alcohol. GET 73, compared to placebo, did not affect the alcohol-related stimulation effects, but increased the subjective sedative effects of alcohol. GET 73 did not affect alcohol cue-induced craving, or alcohol self-administration in the laboratory.

CONCLUSIONS

The study confirms the safety and tolerability of GET 73 when co-administered with alcohol. Although, under this experimental condition, we did not detect an effect on alcohol craving and consumption in the laboratory, additional studies should be conducted administering GET 73 for an extended period in an outpatient setting.

Tapping into 5-HT3 Receptors to Modify Metabolic and Immune Responses

5-hydroxytryptamine type 3 (5-HT₃) receptors are ligand gated ion channels, which clearly distinguish their mode of action from the other G-protein coupled 5-HT or serotonin receptors. 5-HT₃ receptors are well established targets for emesis and gastrointestinal mobility and are used as adjunct targets in treating schizophrenia. However, the distribution of these receptors is wider than the nervous system and there is potential that these additional sites can be targeted to modulate inflammatory and/or metabolic conditions. Recent progress in structural biology and pharmacology of 5-HT₃ receptors have provided profound insights into mechanisms of their action. These advances, combined with insights into clinical relevance of mutations in genes encoding 5-HT₃ subunits and increasing understanding of their implications in patient's predisposition to diseases and response to the treatment, open new avenues for personalized precision medicine. In this review, we recap on the current status of 5-HT₃ receptor-based therapies using a biochemical and physiological perspective. We assess the potential for targeting 5-HT₃ receptors in conditions involving metabolic or inflammatory disorders based on recent findings, underscoring the challenges and limitations of this approach.

A randomized, double-blind, placebo-controlled trial of ondansetron for the treatment of cocaine use disorder with post hoc pharmacogenetic analysis

BACKGROUND

Cocaine use disorder (CUD) has significant consequences and there remain no FDA-approved pharmacotherapies. Ondansetron is an indirect dopaminergic modulator that has shown efficacy in alcohol use disorder, particularly in phenotypic and genotypic subgroups, and was found to be efficacious in a pilot dose-finding trial for CUD.

METHODS

One-hundred eight (108) adults with CUD were randomized to ondansetron 4 mg twice daily or placebo for 9 weeks and assessed up to thrice weekly to evaluate self-reported cocaine use and urine benzoylecgonine. Participants received cognitive-behavioral therapy and brief behavioral compliance enhancement therapy. Consenting participants (N = 79) provided blood samples for exploratory pharmacogenetic analyses.

RESULTS

Participants in both arms reduced cocaine use over time, but there was no statistically significant difference on percentage of cocaine-free days (PCFD; p = 0.972) or percentage of cocaine-free urine samples (PCFU; p = 0.909). Participants with early-onset CUD had greater improvement regardless of study arm (p = 0.002). Post hoc pharmacogenetic analyses demonstrated an interaction effect between treatment and rs1176713 SNP on PCFU in the total sample (p = 0.040) and African ancestry subset (p = 0.03). Constipation, fatigue, and somnolence were more common among ondansetron-treated participants (Fisher exact p < 0.05). Those who developed constipation were mostly rs1176713:GG carriers (Fisher exact p = 0.029).

CONCLUSIONS

Ondansetron did not demonstrate efficacy in the treatment of CUD. However, these preliminary results suggest a genotype-based variance in response to ondansetron in African ancestry individuals with CUD. Further studies are needed to validate findings for developing a personalized genomic approach for CUD treatment in racially and ethnically diverse populations.

The offspring of alcohol-exposed sires exhibit heightened ethanol intake and behavioral alterations in the elevated plus maze

Research suggests that addictive traits are indeed heritable, but very few preclinical studies have explored transgenerational effects of paternal alcohol exposure. The present study addressed this gap in knowledge. We explored whether offspring of ethanol-exposed sires would be more likely to accept ethanol than descendants of water-exposed and control sires. We also investigated whether the second generation of ethanol-exposed descendants would accept ethanol more than controls and were more or less likely to experience anxiety-like behavior in behavioral assessments. We exposed male rats to repeated binge doses of alcohol (4 g/kg/day across 8 days), water, or left them untreated and mated them with untreated females. We then bred the offspring of these rats to test transgenerational effects of paternal alcohol exposure. We tested 14-day-old offspring from the first and second filial generation for their acceptance of ethanol and water, and measured anxiety-like behavior in 38-day-old, second-generation offspring using an elevated plus maze. The results indicate that offspring of ethanol-exposed sires increase ethanol acceptance in the first generation compared to untreated controls, whereas in the second-generation increased ethanol acceptance vs. these controls is seen in descendants of both ethanol- and vehicle-treated sires. At adolescence, the second generation of rats derived from alcohol-exposed sires exhibited significantly more time spent in the open arms and significantly more arm entries than any other group. The present study suggests that parental ethanol exposure is associated with lingering effects in the infant and adolescent offspring. The second filial generation was also found to be affected, albeit similarly by grandparental ethanol exposure or by the stress of the vehicle administration.

Precision medicine: Subgroup identification in longitudinal trajectories

In clinical studies, the treatment effect may be heterogeneous among patients. It is of interest to identify subpopulations which benefit most from the treatment, regardless of the treatment's overall performance. In this study, we are interested in subgroup identification in longitudinal studies when nonlinear trajectory patterns are present. Under such a situation, evaluation of the treatment effect entails comparing longitudinal trajectories while subgroup identification requires a further evaluation of differential treatment effects among subgroups induced by moderators. To this end, we propose a tree-structured subgroup identification method, termed "interaction tree for longitudinal trajectories", which combines mixed effects models with regression splines to model the nonlinear progression patterns among repeated measures. Extensive simulation studies are conducted to evaluate its performance and an application to an alcohol addiction pharmacogenetic trial is presented.

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.

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.

Developing neuroscience-based treatments for alcohol addiction: A matter of choice?

Excessive alcohol use is the cause of an ongoing public health crisis, and accounts for ~5% of global disease burden. A minority of people with recreational alcohol use develop alcohol addiction (hereafter equated with "alcohol dependence" or simply "alcoholism"), a condition characterized by a systematically biased choice preference for alcohol at the expense of healthy rewards, and continued use despite adverse consequences ("compulsivity"). Alcoholism is arguably the most pressing area of unmet medical needs in psychiatry, with only a small fraction of patients receiving effective, evidence-based treatments. Medications currently approved for the treatment of alcoholism have small effect sizes, and their clinical uptake is negligible. No mechanistically new medications have been approved since 2004, and promising preclinical results have failed to translate into novel treatments. This has contributed to a reemerging debate whether and to what extent alcohol addiction represents a medical condition, or reflects maladaptive choices without an underlying brain pathology. Here, we review this landscape, and discuss the challenges, lessons learned, and opportunities to retool drug development in this important therapeutic area.

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.

Therapeutic Prospects of Cannabidiol for Alcohol Use Disorder and Alcohol-Related Damages on the Liver and the Brain

Background: Cannabidiol (CBD) is a natural component of cannabis that possesses a widespread and complex immunomodulatory, antioxidant, anxiolytic, and antiepileptic properties. Much experimental data suggest that CBD could be used for various purposes in alcohol use disorder (AUD) and alcohol-related damage on the brain and the liver. Aim: To provide a rationale for using CBD to treat human subjects with AUD, based on the findings of experimental studies. Methods: Narrative review of studies pertaining to the assessment of CBD efficiency on drinking reduction, or on the improvement of any aspect of alcohol-related toxicity in AUD. Results: Experimental studies find that CBD reduces the overall level of alcohol drinking in animal models of AUD by reducing ethanol intake, motivation for ethanol, relapse, anxiety, and impulsivity. Moreover, CBD reduces alcohol-related steatosis and fibrosis in the liver by reducing lipid accumulation, stimulating autophagy, modulating inflammation, reducing oxidative stress, and by inducing death of activated hepatic stellate cells. Finally, CBD reduces alcohol-related brain damage, preventing neuronal loss by its antioxidant and immunomodulatory properties. Conclusions: CBD could directly reduce alcohol drinking in subjects with AUD. Any other applications warrant human trials in this population. By reducing alcohol-related steatosis processes in the liver, and alcohol-related brain damage, CBD could improve both hepatic and neurocognitive outcomes in subjects with AUD, regardless of the individual's drinking trajectory. This might pave the way for testing new harm reduction approaches in AUD, in order to protect the organs of subjects with an ongoing AUD.

Medication Development for Alcohol Use Disorder: A Focus on Clinical Studies

Compared to other medical disorders, including other brain diseases, the number of medications approved for alcohol use disorder (AUD) is very small. Disulfiram, naltrexone (oral and long-acting), and acamprosate are approved by the US Food and Drug Administration (FDA) to treat patients with AUD. These medications are also approved in other countries, including in Europe, where the European Medicines Agency (EMA) also approved nalmefene for AUD. Furthermore, baclofen was recently approved for AUD in France. These approved medications have small effect sizes, which are probably the consequence of the fact that they only work for some patients, yet a personalized approach to match the right medication with the right patient is still in its infancy. Therefore, research is needed to expand the armamentarium of medications that clinicians can use to treat their patients, as well as to better develop personalized approaches. This book chapter reviews other medications, beyond those approved by the FDA, that have shown efficacy in clinical trials, as well as medications which are still in the early stages of evaluation in human studies.

Association and cis-mQTL analysis of variants in serotonergic genes associated with nicotine dependence in Chinese Han smokers

Variants in serotonergic genes are implicated in nicotine dependence (ND) in subjects of European and African origin, but their involvement with smoking in Asians is largely unknown. Moreover, mechanisms underlying the ND risk-associated single-nucleotide polymorphisms (SNPs) in these genes are rarely investigated. The Fagerström Test for Nicotine Dependence (FTND) score was used to assess ND in 2616 male Chinese Han smokers. Both association and interaction analysis were used to examine the association of variants in the serotonergic genes with FTND. Further, expression and methylation quantitative trait loci (cis-mQTL) analysis was employed to determine the association of individual SNPs with the extent of methylation of each CpG locus. Individual SNP-based association analysis revealed that rs1176744 in HTR3B was marginally associated with FTND (p = 0.042). Haplotype-based association analysis found that one major haplotype, T-T-A-G, formed by SNPs rs3758987-rs4938056-rs1176744-rs2276305, located in the 5' region of HTR3B, showed a significant association with FTND (p = 0.00025). Further, a significant genetic interactive effect affecting ND was detected among SNPs rs10160548 in HTR3A, and rs3758987, rs2276305, and rs1672717 in HTR3B (p = 0.0074). Finally, we found four CpG sites (CpG_4543549, CpG_4543464, CpG_4543682, and CpG_4546888) to be significantly associated with three cis-mQTL SNPs (i.e., rs3758987, rs4938056, and rs1176744) located in our detected haplotype within HTR3B. In sum, we showed SNP rs1176744 (Tyr129Ser) to be associated with ND. Together with the SNPs rs3758987 and rs4938056 in HTR3B, they formed a major haplotype, which had significant association with ND. We further showed these SNPs contribute to ND through four methylated sites in HTR3B. All these findings suggest that variants in the serotonergic system play an important role in ND in the Chinese Han population. More importantly, these findings demonstrated that the involvement of this system in ND is through gene-by-gene interaction and methylation.

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.

Variable selection for random effects two-part models

Random effects two-part models have been applied to longitudinal studies for zero-inflated (or semi-continuous) data, characterized by a large portion of zero values and continuous non-zero (positive) values. Examples include monthly medical costs, daily alcohol drinks, relative abundance of microbiome, etc. With the advance of information technology for data collection and storage, the number of variables available to researchers can be rather large in such studies. To avoid curse of dimensionality and facilitate decision making, it is critically important to select covariates that are truly related to the outcome. However, owing to its intricate nature, there is not yet a satisfactory variable selection method available for such sophisticated models. In this paper, we seek a feasible way of conducting variable selection for random effects two-part models on the basis of the recently proposed "minimum information criterion" (MIC) method. We demonstrate that the MIC formulation leads to a reasonable formulation of sparse estimation, which can be conveniently solved with SAS Proc NLMIXED. The performance of our approach is evaluated through simulation, and an application to a longitudinal alcohol dependence study is provided.

Pharmacotherapy for Alcohol Use Disorder

Alcohol use disorder is a common, destructive, and undertreated disease. As understanding of alcohol use disorder has evolved, so has our ability to manage patients with pharmacotherapeutic agents in addition to nondrug therapy, including various counseling strategies. Providers now have a myriad of medications, both approved and not approved by the US Food and Drug Administration, to choose from and can personalize care based on treatment goals, comorbidities, drug interactions, and drug availability. This review explores these treatment options and offers the prescriber practical advice regarding when each option may or may not be appropriate for a specific patient.

Advances in Pharmacotherapy Development: Human Clinical Studies

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

The Corticotropin Releasing Factor Receptor 1 in Alcohol Use Disorder: Still a Valid Drug Target?

Corticotropin releasing factor (CRF) is a neuropeptide that plays a key role in behavioral and physiological responses to stress. A large body of animal literature implicates CRF acting at type 1 CRF receptors (CRFR1) in consumption by alcohol-dependent subjects, stress-induced reinstatement of alcohol seeking, and possibly binge alcohol consumption. These studies have encouraged recent pilot studies of CRFR1 antagonists in humans with alcohol use disorder (AUD). It was a great disappointment to many in the field that these studies failed to show an effect of these compounds on stress-induced alcohol craving. Here, we examine these studies to explore potential limitations and discuss preclinical and human literature to ask whether CRFR1 is still a valid drug target to pursue for the treatment of AUD.

Genotype combination contributes to psoriasis: An exhaustive algorithm perspective

Researchers have learned that nearly all conditions and diseases have a genetic component. With the benefit of technological advances, many single-nucleotide polymorphisms (SNPs) have been found to be associated with the risk of complex disorders by using genome wide association studies (GWASs). Disease-associated SNPs are sometimes shared by healthy controls and cannot clearly distinguish affected individuals from unaffected ones. The combined effects of multiple independent SNPs contribute to the disease process, but revealing the relationship between genotype and phenotype based on the combinations remains a great challenge. In this study, by considering the disease prevalence rate, we conducted an exhaustive process to identify whether a genotype combination pattern would have a decisive effect on complex disorders. Based on genotype data for 68 reported SNPs in 8,372 psoriasis patients and 8,510 healthy controls, we found that putative causal genotype combination patterns (CGCPs) were only present in psoriasis patients, not in healthy subjects. These results suggested that psoriasis might be contributed by combined genotypes, complementing the traditional modest susceptibility of a single variant in a single gene for a complex disease. This work is the first systematic study to analyze genotype combinations based on the reported susceptibility genes, considering each individual among the cases and controls from the Chinese population, and could potentially advance disease-gene mapping and precision medicine due to the causality relationship between the candidate CGCPs and complex diseases.

Promising pharmacogenetic targets for treating alcohol use disorder: evidence from preclinical models

Inherited genetic variants contribute to risk factors for developing an alcohol use disorder, and polymorphisms may inform precision medicine strategies for treating alcohol addiction. Targeting genetic mutations linked to alcohol phenotypes has provided promising initial evidence for reducing relapse rates in alcoholics. Although successful in some studies, there are conflicting findings and the reports of adverse effects may ultimately limit their clinical utility, suggesting that novel pharmacogenetic targets are necessary to advance precision medicine approaches. Here, we describe promising novel genetic variants derived from preclinical models of alcohol consumption and dependence that may uncover disease mechanisms that drive uncontrolled drinking and identify novel pharmacogenetic targets that facilitate therapeutic intervention for the treatment of alcohol use disorder.

Guidelines for biological treatment of substance use and related disorders, part 1: Alcoholism, first revision

These practice guidelines for the biological treatment of alcohol use disorders are an update of the first edition, published in 2008, which was developed by an international Task Force of the World Federation of Societies of Biological Psychiatry (WFSBP). For this 2016 revision, we performed a systematic review (MEDLINE/PUBMED database, Cochrane Library) of all available publications pertaining to the biological treatment of alcoholism and extracted data from national guidelines. The Task Force evaluated the identified literature with respect to the strength of evidence for the efficacy of each medication and subsequently categorised it into six levels of evidence (A-F) and five levels of recommendation (1-5). Thus, the current guidelines provide a clinically and scientifically relevant, evidence-based update of our earlier recommendations. These guidelines are intended for use by clinicians and practitioners who evaluate and treat people with alcohol use disorders and are primarily concerned with the biological treatment of adults with such disorders.

Differential potassium channel gene regulation in BXD mice reveals novel targets for pharmacogenetic therapies to reduce heavy alcohol drinking

Alcohol (ethanol) dependence is a chronic relapsing brain disorder partially influenced by genetics and characterized by an inability to regulate harmful levels of drinking. Emerging evidence has linked genes that encode K_V7, K_IR, and K_Ca2 K⁺ channels with variation in alcohol-related behaviors in rodents and humans. This led us to experimentally test relations between K⁺ channel genes and escalation of drinking in a chronic-intermittent ethanol (CIE) exposure model of dependence in BXD recombinant inbred strains of mice. Transcript levels for K⁺ channel genes in the prefrontal cortex (PFC) and nucleus accumbens (NAc) covary with voluntary ethanol drinking in a non-dependent cohort. Transcripts that encode K_V7 channels covary negatively with drinking in non-dependent BXD strains. Using a pharmacological approach to validate the genetic findings, C57BL/6J mice were allowed intermittent access to ethanol to establish baseline consumption before they were treated with retigabine, an FDA-approved K_V7 channel positive modulator. Systemic administration significantly reduced drinking, and consistent with previous evidence, retigabine was more effective at reducing voluntary consumption in high-drinking than low-drinking subjects. We evaluated the specific K⁺ channel genes that were most sensitive to CIE exposure and identified a gene subset in the NAc and PFC that were dysregulated in the alcohol-dependent BXD cohort. CIE-induced modulation of nine genes in the NAc and six genes in the PFC covaried well with the changes in drinking induced by ethanol dependence. Here we identified novel candidate genes in the NAc and PFC that are regulated by ethanol dependence and correlate with voluntary drinking in non-dependent and dependent BXD mice. The findings that Kcnq expression correlates with drinking and that retigabine reduces consumption suggest that K_V7 channels could be pharmacogenetic targets to treat individuals with alcohol addiction.

Review: Pharmacogenetics of alcoholism treatment: Implications of ethnic diversity

BACKGROUND AND OBJECTIVES

Pharmacogenetic studies of alcohol use disorder (AUD) have suggested that the efficacy of treatments for AUD is, in part, influenced by the genetic background of an individual. Since the frequency of alleles associated with pharmacotherapy for AUD varies by ancestral background, the effectiveness of medications used to treat AUD may vary among different populations. The purpose of this review is to summarize the existing pharmacogenetic studies of treatments for AUD in individuals of European, East Asian, African, and American Indian/Alaska Native ancestry.

METHODS

Electronic databases were searched for pharmacogenetic studies of AUD treatment that included individuals of diverse ancestral backgrounds.

RESULTS

Pharmacogenetic studies of AUD reviewed here have primarily investigated genetic variation thought to play a role in the response to naltrexone, ondansetron, and topiramate. There is support that the A118G polymorphism should be further investigated in individuals of East Asian ancestry.

DISCUSSION AND CONCLUSIONS

Given the lack of pharmacogenetic research on response to AUD medication in ethnic minority populations and the mixed results, there is a critical need for future studies among individuals of different ancestries. More efforts should be devoted to standardizing procedures such that results can be more readily integrated into a body of literature that can directly inform clinical practice.

SCIENTIFIC SIGNIFICANCE

This review highlights the importance for future research to aim for inclusiveness in pharmacogenetic studies of AUD and increase diversity of clinical trials in order to provide the best treatment outcomes for individuals across different racial and ethnic groups. (Am J Addict 2017;26:516-525).

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.

From genetic studies to precision medicine in alcohol dependence

Genetic factors contribute to more than 50% of the variation in the vulnerability to alcohol dependence (AD). Although significant advances have been made in medications for AD, these medications do not work for all people. Precise tailoring of medicinal strategies for individual alcoholic patients is needed to achieve optimal outcomes. This review updates the most promising information on genetic variants in AD, which may be useful for improving diagnostic, therapeutic, and monitoring strategies. We describe genetic candidates of various neurotransmitter and enzyme systems. In addition to biological and allelic associations with AD, genetic effects on AD-related phenotypes and treatment responses have also been described. Gene-gene and gene-environment interactions have been considered. Potential applications of genomewide and epigenetic approaches for identifying genetic biomarkers of AD have been discussed. Overall, the application of genetic findings in precision medicine for AD will likely involve an integrated approach that distinguishes effect sizes of specific genetic predictors with regard to sex, pharmacotherapy, ethnicity, and AD-related aspects and considers gene-gene and gene-environment interactions. Our work may pave the way toward more precise treatment for AD that could ultimately improve clinical management and interventions.

Medications between psychiatric and addictive disorders

INTRODUCTION

Many epidemiological studies have revealed a frequent co-occurrence of psychiatric and substance use disorders. The term used in the literature to refer to this co-occurrence is dual diagnosis. The high prevalence of dual diagnosis has led physicians to observe the effects of medication prescribed to treat psychiatric disorders on the co-occurring substance use disorder and vice versa. The concept of medications between psychiatric and addictive disorders stems from these clinical observations, alongside which, however, it has developed from the observation that both psychiatric and substance use disorders share common neurobiological pathways and trigger common cognitive disorders. This has led researchers to develop medications on the basis of neurobiological and cognitive rationales.

MATERIAL AND METHOD

In our article, we review peculiar medications based on neurobiological and cognitive rationales and that have an impact in both psychiatric and addictive disorders.

RESULTS

We highlight how interesting these new prescriptions are for clinical observation and for the treatment of patients suffering from dual diagnosis.

CONCLUSION

We then go on to discuss the interest in them from the perspective of clinical practice and clinical research, in that the development of medications to treat dual diagnosis helps to further our knowledge of both psychiatric and substance use disorders.

METHYLATION OF SEROTONIN RECEPTOR 3A IN ADHD, BORDERLINE PERSONALITY, AND BIPOLAR DISORDERS: LINK WITH SEVERITY OF THE DISORDERS AND CHILDHOOD MALTREATMENT

BACKGROUND

Serotonin 3A receptor (5-HT3A R) is associated at the genetic and epigenetic levels with a variety of psychiatric disorders and interacts with early-life stress such as childhood maltreatment. We studied the impact of childhood maltreatment on the methylation status of the 5-HT3A R and its association with clinical severity outcomes in relation with a functional genetic polymorphism.

METHODS

Clinical severity indexes of 346 bipolar, borderline personality, and adult attention deficit hyperactivity disorders patients were tested for association with the DNA methylation status of eight 5-HT3A R gene CpGs. Relationship between the functional variant rs1062613 (C > T) and methylation status on severity of the disorders were also assessed.

RESULTS

Childhood maltreatment was associated with higher severity of the disease (higher number of mood episodes, history of suicide attempts, hospitalization, and younger age at onset) across disorders and within each individual disorder. This effect was mediated by two 5-HT3A R CpGs. Compared to T allele carriers, CC carriers had higher methylation status at one CpG located 1 bp upstream of this variant.

CONCLUSIONS

This study shows that epigenetic modification of the 5-HT3A R is involved in the mechanism underlying the relationship between maltreatment in childhood and the severity of several psychiatric disorders in adulthood.

What the alcohol doctor ordered from the neuroscientist: Theragnostic biomarkers for personalized treatments

Major advances in the neuroscientific understanding of alcohol actions have so far not translated into measurably improved clinical outcomes in alcoholism. Future treatment development should be guided by accumulating insights into a diverse range of biological mechanisms that maintain the pathophysiology of alcoholism in different individuals, but also at different points in time within any given patient. This biological diversity calls for the development and use of biological markers predictive of treatment response in the individual case, at the specific stage of the disease, here called "theragnostics." As novel therapeutic mechanisms and molecules targeting these mechanisms are discovered, the use of theragnostics will be critical for their successful clinical development, as well as their optimal subsequent clinical use. During clinical development, lest theragnostics are utilized, efficacy signals will risk remaining undetected when diluted in study populations that are not appropriately selected. Similarly, for treatments that reach approval, clinical acceptance, and optimal use will require the proper identification of responsive patients. Here, we discuss desirable properties of theragnostic biomarkers in alcohol addiction using two examples: alcohol-induced activation of brain reward circuitry as assessed using positron emission tomography of functional magnetic resonance imaging; and central glutamate tone, as assessed using MR spectroscopy.

Developing a Risk Score to Guide Individualized Treatment Selection in Attention Deficit/Hyperactivity Disorder

OBJECTIVE

To develop a risk score for treatment failure that could potentially be used to individualize treatment selection between lisdexamfetamine dimesylate (LDX) and osmotic-release oral system methylphenidate (OROS-MPH) in children and adolescents with attention deficit/hyperactivity disorder (ADHD).

METHODS

The study used data from patients with ADHD receiving LDX (N = 104) or OROS-MPH (N = 107) in a phase III randomized clinical trial. A prediction model was developed to estimate risk scores for failing OROS-MPH, where treatment failure was defined as less than 25% improvement in the ADHD Rating Scale IV total score from baseline. Patients were ranked by their predicted risks of OROS-MPH failure to define high-risk subpopulations. Outcomes of LDX and OROS-MPH were compared within subpopulations.

RESULTS

The prediction model for OROS-MPH failure selected seven predictors (age, disease duration, and five ADHD Rating Scale IV item scores) and had an in-sample C statistic of 0.860. Among all patients, LDX had a 17% (95% confidence interval 7.1%-27.8%) lower treatment failure rate than that of OROS-MPH; differences in failure rates ranged from 17% to 43% across subpopulations, increasingly enriched for high-risk patients. Similar heterogeneity across subgroups was observed for other efficacy measures.

CONCLUSIONS

In the overall trial population, LDX was associated with a lower rate of treatment failure compared with OROS-MPH in patients with ADHD. A more pronounced benefit of LDX over OROS-MPH was observed among subpopulations with a higher predicted risk of failing OROS-MPH. The present study showed the feasibility of individualizing treatment selection. Future research is needed to prospectively verify these results.

Variation in the Serotonin Transporter Gene and Alcoholism: Risk and Response to Pharmacotherapy

SLC6A4, the gene encoding the serotonin transporter protein (5-HTT), has been extensively examined as a risk factor for alcohol dependence (AD). More recently, variability in the transporter gene was identified to be a potential moderator of treatment response to serotonergic medications such as ondansetron and sertraline. There is an insertion-deletion polymorphism in the promoter region (5-HTTLPR) of the SLC6A4, with the most common alleles being a 14-repeat short (S) allele and a 16-repeat long (L) allele. The S allele has often been associated with AD. By contrast, the L allele has been associated with pharmacological responsiveness in some individuals with AD. Differences in clinical phenotype may determine the utility of the 5-HTTLPR polymorphism as a moderator of pharmacological interventions for AD. We review the AD typology and disease onset in the context of pharmacogenetic and genomic studies that examine the utility of 5-HTTLPR in improving treatment outcomes.