Alcoholism: Clinical and Experimental Research

Stress exposure contributes to the development of drug and alcohol use disorders. In animal models, stress exacerbates escalations in alcohol consumption in alcohol-dependent animals. The nucleus of the solitary tract (NTS) is a critical brainstem region for integrating and relaying peripheral signals to regulate stress responses. To define the molecular adaptions within this brain region that may contribute to stress-induced alcohol drinking, we exposed animals to chronic intermittent bouts of ethanol vapor (CIE), forced swim stress (FSS), or both (CIE + FSS) and then transcriptionally profiled the NTS at three different timepoints after the last vapor exposure (0-hr, 72-hr, and 186-hr). We identified interferon (IFN) signaling as a critical gene network correlated with alcohol consumption levels. Using a likelihood ratio test, we identified genes that were differentially expressed across time and between groups. Clustering analysis of these genes to identify unique expression patterns identified a subset of genes that fail to normalize in the CIE + FSS group, but not the others. These genes were enriched for cell-to-cell interaction and cellular movement pointing to long-term structural and functional changes in this brain region caused by the unique interaction of alcohol dependence and stress. Specific genes of interest identified in this group include Aqp4, Il16, Reln, Grm4, Gabrd, and Gabra6. We also compared gene expression changes in the NTS to the PFC and found a significant overlap of genes between the two brain regions. Overlapping NTS/PFC genes in the CIE + FSS group were enriched for type I IFN signaling. Finally, we tested the hypothesis that activation of type I IFN signaling increases alcohol consumption based on the three lines of evidence identifying type I IFN signaling as critical for escalations in alcohol intake. Mice treated with recombinant IFN{beta} showed significantly elevated levels of alcohol intake in a two-bottle choice procedure compared to saline-treated controls. Overall, these results define the transcriptomic changes across time in the NTS that may be critical to the development of stress-induced increases in alcohol consumption and alcohol dependence.

Alcohol use disorder (AUD) imposes a significant global health burden, yet effective treatments remain limited due to the scarcity of well-characterized biological sample repositories. To address this gap, we established the UCSD Alcohol BioBank, a comprehensive resource containing thousands of samples from over 700 genetically diverse heterogeneous stock (HS) rats. Modeled after successful cocaine and oxycodone biobanks, this repository utilizes the chronic intermittent ethanol vapor exposure (CIE) model, paired with oral self-administration, to characterize AUD-like behaviors, including ethanol consumption, preference, motivation, and withdrawal symptoms such as allodynia and anxiety-like behavior. Longitudinal samples (blood, urine, and feces) are collected before, during, and after ethanol exposure, while terminal samples (brain, heart, liver, kidneys, cecum, reproductive organs, adrenal glands, peripheral blood mononuclear cells) are obtained at intoxication, acute withdrawal, protracted abstinence, or from naive controls. Samples are preserved via snap-freezing or paraformaldehyde fixation to support diverse applications, including genomics, transcriptomics, proteomics, and neuroanatomy. The genetic diversity of HS rats enables genome-wide association studies (GWAS) to identify AUD-related genetic variants. Freely available to non-profit organizations at www.alcoholbiobank.org, with genetic and behavioral data deposited in public repositories, the Alcohol BioBank facilitates collaborative research to uncover biomarkers and develop novel therapies for AUD, addressing a critical need in addiction science.

BackgroundStudies show that Black and Hispanic Veterans have a higher prevalence of alcohol use disorder (AUD) than White Veterans. We examined whether the relationship between self-reported race/ethnicity and AUD diagnosis varies by self-reported alcohol consumption. MethodsThe sample included 700,013 Black, Hispanic, and White Veterans enrolled in the Million Veteran Program cohort. Alcohol consumption was defined as an individuals maximum score on the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) questionnaire, a screen for hazardous or harmful drinking. The primary outcome, AUD, was defined by the presence of ICD-9/10 codes in the electronic health record. We used logistic regression with interactions to assess the association between race/ethnicity and AUD by maximum AUDIT-C score. ResultsBlack and Hispanic Veterans were more likely to have an AUD diagnosis than White Veterans despite similar levels of alcohol consumption. The difference was greatest between Black and White men. At all but the lowest and highest levels of alcohol consumption, Black men had 24%-111% greater odds of an AUD diagnosis. The association between race/ethnicity and AUD diagnosis remained after adjustment for alcohol consumption, alcohol-related disorders, and other potential confounders. ConclusionsThe large discrepancy in AUD diagnosis across groups despite a similar distribution of alcohol consumption measures suggests that Veterans are differentially assigned an AUD diagnosis by race/ethnicity. Efforts are needed to examine the causes of the observed differences and to implement changes, such as structured diagnostic methods, to address a likely contributor to racial differences (i.e., bias) in AUD diagnosis.

This study explores the neurobiological underpinnings of alcohol use disorder (AUD) by integrating bulk and single-cell transcriptomic data from humans, primates, and mice across three brain regions associated with addiction (i.e., prefrontal cortex (PFC), nucleus accumbens (NAc), and central amygdala (CeA)). We compared AUD RNA expression and cell-type abundance from 92 human brain to data from 53 primates and 90 mice engaged in diverse alcohol use paradigms. The findings revealed significant and reproducible correlations between human AUD and mammalian models of alcohol use that vary by tissue, species, and behavioral paradigm. The strongest correlations occurred between primate and mouse models of binge drinking (i.e., high drinking in the dark). Certain primate models demonstrated that the brain RNA correlations with human alcohol use disorder (AUD) were approximately 40% as strong as the correlations observed within human samples themselves. By integrating single-cell transcriptomic data, this study observed decreased oligodendrocyte proportions in the PFC and NAc of human AUD with similar trends in animal models. Gene co-expression network analyses revealed conserved systems associated with human AUD and animal models of heavy/binge alcohol consumption. Gene co-expression networks were enriched for pathways related to inflammation, myelination, and synaptic plasticity and the genes within them accounted for [~]20% of the heritability in human alcohol consumption. Identified hub genes were associated with relevant traits (e.g., impulsivity, motivation) in humans and mice. This study sheds light on conserved biological entities underlying AUD and chronic alcohol use, providing insights into the cellular, genetic, and neuromolecular basis across species.

BackgroundAlcohol is the most widely consumed psychoactive substance worldwide. In Portugal, alcohol consumption is deeply embedded in social and cultural practices, contributing to high prevalence rates among university students, with binge drinking emerging as a predominant consumption pattern. Despite the associations between this drinking behaviour and numerous social, physical, and psychological problems, research on alcohol consumption in Portuguese university populations remains limited. Thus, this study aimed to provide a comprehensive description of alcohol use patterns among a large sample of Portuguese university students, focusing on adolescents and young adults. MethodsA total of 1,746 students, aged 17-24 years, were surveyed using the Alcohol Use Disorders Identification Test (AUDIT) and additional questionnaires regarding socio-demographic information, alcohol and illicit drug use, smoking habits, and alcohol cravings. Students were classified into five drinking groups: Abstainers (16.8%), Moderate Drinkers (35.1%), Hazardous Drinkers (25.8%), Binge Drinkers (20.8%), and Dependent Drinkers (1.5%). Statistical analyses included descriptive statistics, group comparisons, and multinomial logistic regressions to obtain Odds Ratios (ORs) for group membership. ResultsAlcohol consumption was reported by 83.2% of students over the past year. Nearly 47% of students revealed harmful drinking patterns, and 1.5% exhibited symptoms of alcohol dependence. A progressive increase in the severity of alcohol consumption characteristics was observed across the groups, with Dependent Drinkers reporting the highest levels overall. Significant predictors of group membership included polydrug use, standard weekly consumption, earlier drinking onset, and higher levels of alcohol craving. Polydrug use, reported by 27.3% of students, was the strongest predictor for being a Hazardous Drinker (OR = 10.75), Binge Drinker (OR = 13.20), and Dependent Drinker (OR = 21.40). Binge Drinkers displayed standard weekly consumption and craving levels comparable to Dependent Drinkers, while Moderate Drinkers exhibited the least risky patterns, including a later age of onset of drinking. Male students reported significantly greater consumption and craving levels than their female peers. ConclusionsThis study highlights the prevalence of harmful drinking behaviours among Portuguese university students and identifies critical risk factors, such as polydrug use and early drinking onset. These findings underscore the need for prevention programmes focused on delaying the onset of alcohol use, reducing polydrug use, and promoting healthier behaviours within academic settings.

BackgroundGenetic influences account for a substantial proportion of individual differences in alcohol use behaviors (AUBs). However, multiple distinct sets of genes are linked to different AUBs, which may explain their dramatic variability in risk factors and manifestations. In this study, we explore whether intermediate neurobiological traits and alcohol-related cognitions mediate the relationship between polygenic scores (PGS) and multiple AUBs, with the aim to better understand processes captured by different genetic profiles. MethodsUsing results from prior genome-wide association studies, we derived PGS for 6 AUBs in participants from Spit for Science, a longitudinal study of college students in the U.S. (n=4,549). Self-report measures included personality traits, alcohol expectancies, drinking motivations, and alcohol sensitivity measures as well as drinking frequency, drinking quantity, alcohol use disorder (AUD) symptoms, and maximum drinks in 24 hours. Using linear regression and multiple mediation models, we investigated the direct and indirect effects of PGS on AUBs. ResultsIn univariable regression results, PGSs indexing broad AUB dimensions such as drinks per week (DPW) and AUD predicted higher levels of sensation-seeking and multiple drinking motives, while BeerPref PGSs (indexing a variable pattern of alcohol problems associated with a preference for beer) predicted higher negative urgency and lower alcohol sensitivity. Mediational models indicated strong direct and indirect effects of DPW PGSs on multiple AUBs via social/enhancement drinking motives and alcohol sensitivity, indirect effects of AUD PGSs on AUD symptoms via coping motives, and indirect effects of BeerPref PGS on all AUBs via the joint effect of mediators including alcohol sensitivity. ConclusionsThese findings provide initial evidence that the genetic influences on different AUBs are associated with and partially mediated by intermediate neurobiological and cognitive factors, which may be more amenable to intervention. Greater focus on drinking motives and alcohol sensitivity is warranted in genetic research, as well as attention to the heterogeneous pathways linking genes to alcohol use outcomes.

BackgroundMethamphetamine addiction remains a significant public health concern, primarily affecting the central nervous system by disrupting dopamine and serotonin signaling. Epigenetic modifications, especially DNA methylation in the catechol-O-methyltransferase (COMT) and serotonin transporter (SLC6A4) genes, are implicated in addiction-related behavioral changes. While previous research has examined these genes, this study provides a novel perspective by analyzing methylation patterns in relation to aggression subtypes and methamphetamine use behaviors within a Middle Eastern cohort--an underrepresented population in addiction genetics. AimsTo investigate the genetic and epigenetic factors associated with methamphetamine addiction and aggression, with a specific focus on methylation profiles of the SLC6A4 and COMT genes. MethodsSixty male patients with methamphetamine addiction and aggression, and thirty age-matched healthy controls were enrolled. Peripheral blood samples were collected for RNA and DNA extraction. Methylation levels were assessed via bisulfite sequencing, and gene expression was evaluated using qRT-PCR. Behavioral data and substance use patterns were recorded through structured assessments. ResultsPatients showed significantly higher methylation levels in the SLC6A4 (63.29% vs. 7.84%, p = 0.0001) and COMT(50.98% vs. 19.77%, p = 0.0001) genes compared to controls. A strong correlation was observed between dopamine and methamphetamine levels (r = 0.846, p < 0.001). Methylation levels varied by aggression subtype and drug use frequency, suggesting epigenetic involvement in addiction severity and behavioral traits. ConclusionsThis study supports the role of SLC6A4 and COMT gene methylation in methamphetamine addiction and aggression. While causality cannot be inferred, the findings encourage further investigation into epigenetic biomarkers for behavioral risk profiling. Broader, longitudinal studies are needed to evaluate therapeutic potential and inform ethically sound applications in personalized addiction treatment.

Understanding the neurobiological systems that regulate alcohol cue-induced craving is of utmost importance for the development of novel intervention strategies for alcohol use disorders (AUDs). However, although a human experimenter is required to conduct alcohol self-administration studies in the lab, the cues associated with the experimenter are seldom if ever factored into the experimental design. Thus, although we have learned much to date about alcohol cue-induced behavior and neurobiology, and in particular about discrete cues presented many times throughout a single daily alcohol self-administration session, we know relatively little about how responses to alcohol availability cues might predict subsequent alcohol consumption. For the current experiment, mice were exposed daily to auditory cues that preceded 2 hours of alcohol or water access using drinking-in-the-dark (DID) methods. An additional control group experienced cues but were not otherwise manipulated. Importantly, cues were initiated remotely from outside the animal facility, avoiding the experimenter being the first cue predicting ethanol availability. Head direction, location in the home cage, and movement velocity were the primary variables on interest. Surprisingly, during the cue period, there were no significant differences between groups in any of these measures, despite meaningful alterations over days. However, we observed many significant correlations between behaviors and drinking variables. First, we observed significant positive associations between ambulatory velocity during cues and subsequent total alcohol (R2=0.14; p<0.0001) and total water (R2=0.12; p=0.0002) consumption, but only in females. We also observed a significant positive relationship (R2=0.25; p<0.0001) between the amount of time oriented toward the sipper port during the auditory cues and the average rate of subsequent alcohol consumption (i.e. front-loading), but only in females. In males, head direction was found to be positively associated with subsequent total water consumption (R2=-0.21; p<0.0001), but not alcohol (R2=-0.01; p=0.2267). We also observed a significant negative relationship (R2=-0.15; p<0.0001) between proximity to the sipper during the cue period and subsequent total 2-hour alcohol intake in males. Although these associations were modest in strength, they suggest potential sex-specific behavioral predictors of alcohol consumption that are regulated by different neural dynamics.

RationaleIn humans, alcohol drinking is a significant driver of violent behaviors such as assaults and homicides. While acute intoxication is known to produce heightened aggression, little is known about alcohols long-term effects. Emerging evidence, however, suggests that chronic alcohol intake can promote heightened aggression, including during abstinence and may also sensitize individuals to alcohols acute aggression-heightening effects. ObjectivesThe goal of this study was to test the effects of chronic binge-like ethanol drinking on both alcohol-involved and alcohol-uninvolved aggression in male CFW mice. We aimed to model individual differences in binge drinking and assess changes in aggression during both acute and protracted abstinence. ResultsAfter 5 weeks of Drinking in the Dark (DID), CFW mice that showed higher levels of EtOH drinking ( high drinkers, 1.33 g/kg/h) became more aggressive than low drinkers (0.45 g/kg/h) and H2O controls, as measured via frequency of attack bites during resident-intruder fighting. In the first aggressive encounter following 1 week of abstinence, animals with an alcohol drinking history initiate a fight more rapidly and with greater consistency than H2O controls. We also found that a single session of binge-like alcohol drinking acutely heightened aggression regardless of drinking history. ConclusionsThese results suggest that repeated binge-like alcohol drinking causes escalations in alcohol-uninvolved aggression during acute (in high drinkers) and protracted abstinence (in all alcohol drinkers). However, chronic alcohol intake does not appear to sensitize animals to alcohol-involved aggression. These findings support the utility of genetically heterogeneous CFW mice for modeling individual variability in alcohol-related aggression.

ObjectiveFetal alcohol spectrum disorders affect approximately 1 in 20 school age children in the United States of America. To study fetal alcohol spectrum disorders, mouse models are commonly used. Of the many approaches of gestational exposure, voluntary drinking paradigms represent the most similar mechanism of drinking as human exposure. These exposures can be done through low-tech solutions such as test tubes (TT), or more high-tech methods such as a volumetric drinking monitor (VDM). Here were compare the TT method and the VDM directly, to evaluate their effect on female mouse drinking. MethodWe adapted a drinking in the dark, active cycle, limited access (4 hr.) voluntary drinking paradigm first described by Brady et al. (2012) to test tubes and the volumetric drinking monitor. 8 mice were placed in either drinking method and we evaluated their drinking volume and blood alcohol concentrations (BACs). We compared the values for each group using t-tests. ResultsAfter 2 weeks of drinking 10% ethanol with 0.4% saccharine, BACs were not significantly different [t(14)=0.2681, p=0.7935] between the VDM (81.56 {+/-} 21.16 mg/dL) vs.TT (73.14 {+/-} 23.20 mg/dL) groups. Calculated intake of ethanol (g/kg) on the day of blood draw for BAC analysis was also not significantly different [t(14)=0.4308, p=0.6732] between VDM (2.985 {+/-} 0.4127) vs.TT (3.260 {+/-} 0.4863; Fig 1B) groups. O_FIG O_LINKSMALLFIG WIDTH=139 HEIGHT=200 SRC="FIGDIR/small/658718v1_fig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@5f3ad4org.highwire.dtl.DTLVardef@f45edorg.highwire.dtl.DTLVardef@b7d7f8org.highwire.dtl.DTLVardef@1c40c63_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFig 1.C_FLOATNO C_FIG ConclusionsTest tube or VDM resulted in similar average daily ethanol consumption and resultant BACs in female mice

AbstractDespite decades of research, no new FDA-approved medications for alcohol use disorder (AUD) have emerged in over 25 years. Enhancing the translational relevance of preclinical models by more precisely capturing the behavioral and neurobiological features of AUD offers a promising path toward identifying novel therapeutic targets. Operant self-administration paradigms are essential for modeling voluntary ethanol intake in rodents, yet traditional approaches often confound appetitive (seeking) and consummatory (intake) behaviors. The sipper model addresses this limitation by allowing extended, uninterrupted access to ethanol following operant responding, enabling a clearer dissociation between seeking and consumption. In this review, we synthesize key findings from studies employing the sipper model to investigate the behavioral and neurobiological mechanisms underlying alcohol use. We emphasize how over two decades of research employing the sipper model have demonstrated that ethanol- directed behaviors are dynamic processes, shaped by internal states, environmental cues, and prior experience. Finally, we introduce medparser, a new open-source R package designed to standardize the analysis of high-resolution licking data generated by sipper paradigms. By promoting reproducibility and cross-study comparability, this tool supports rigorous behavioral phenotyping. Together, these methodological and analytical advances enhance the translational potential of preclinical models and may ultimately aid in the discovery of novel therapeutic targets for AUD.

Excessive alcohol (ethanol) consumption is a hallmark of alcohol use disorder (AUD). Activation of innate immune system and proinflammatory signaling in the brain may play a key role in promoting alcohol consumption and development of AUD in humans. Innate immune activation by toll-like receptor (TLR) agonists in rodents is associated with release of proinflammatory cytokines and changes in alcohol consumption, and these effects are genotype- and sex-dependent. For example, C57BL/6J male, but not female mice increase alcohol intake after TLR3 activation. In order to better understand the interactions between neuroimmune signaling, genotype, and sex and their effects on ethanol drinking, males and females of more genotypes need to be tested. The goal of this study was to test the effects of innate immune activation on ethanol consumption and neuroimmune molecular profiles of F1 hybrid mice from reciprocal crosses between C57BL/6J (B6) and FVB/NJ (FVB) mouse strains, which are animals with high levels of ethanol intake. Animals were randomly assigned to receive intraperitoneal injections of either saline, Poly(I:C) (PIC, 2 or 10 mg/kg), a TLR3 agonist, or lipopolysaccharide, (LPS, 0.1 mg/kg), a TLR4 agonist, administered every 4 days for a total of 10 injections and subjected to a 2-bottle choice every-other-day ethanol drinking paradigm for a total of 18 dinking sessions, which generated high levels of voluntary ethanol consumption. Six and 24 hours after the last injection, brains were removed, frontal cortex dissected, and levels of 3 proinflammatory cytokines (Tnfa, Il1b, Ccl5), as well as Tlr3, and Tlr4 were measured using qPCR. Immune activation by PIC produced escalation of ethanol drinking, while LPS resulted in a reduction of ethanol consumption or a trend to reduce drinking in males but not females of both FVB/B6 and B6/FVB crosses. Furthermore, activation of TLR3 by PIC produced sex-specific time course responses of pro-inflammatory cytokines, which may, at least in part, explain behavioral differences. Taken together, these results validate previous findings that the effects of immune activation on ethanol consumption depend on genotype, sex, and mode of activation (TLR3 vs TLR4) and suggest that FVB/B6J and B6J/FVB F1 males are a suitable model to study TLR3-dependent escalation of alcohol drinking. HighlightsO_LIImmune activation by Toll-like receptor 3 (TLR3) agonist, Poly(I:C), produced an escalation of ethanol drinking, while immune activation by TLR4 agonist, LPS, reduced ethanol intake in male but not female FVB/NJ x C57BL/6J hybrid mice. C_LIO_LIPoly(I:C)-induced escalation of alcohol consumption in males was reproducible and consistent across different Poly(I:C) doses. C_LIO_LIActivation of TLR3 by Poly(I:C) produced sex-specific time course responses of pro-inflammatory cytokines, which may, at least in part, explain sex differences in alcohol consumption. C_LIO_LIOur data suggest that FVB/NJ x C57BL/6J hybrid male mice are a suitable model to study TLR3-dependent escalation of alcohol drinking. C_LI

Food addiction (FA) has been proposed as a phenotype sharing features with substance use disorders. Despite increasing recognition of food addiction as a behavioral phenotype with features overlapping substance use disorders, little is known about its prevalence or clinical significance among individuals with alcohol use disorder (AUD). Objective: To examine the prevalence of FA and to evaluate demographic, psychological, and alcohol-related correlates in individuals with AUD. Design, Setting, and Participants: This cross-sectional analysis included 743 adults with AUD who were either treatment seeking (Tx) (n = 534) for AUD and were enrolled in an inpatient program at the National Institutes of Health Clinical Center or not treatment-seeking (non Tx) (n = 209). Main Outcomes and Measures: FA symptoms were assessed using the Yale Food Addiction Scale, with >=2 symptoms categorized as FA in this report. Multivariable logistic regression models adjusted for age, education, and income were conducted separately within each cohort. Results: Among 743 adults with AUD, 238 (32.1%) met criteria for FA symptoms, with similar prevalence among Tx (32.6%) and nonTx (30.6%) participants despite marked differences in clinical characteristics. Across both cohorts, FA was independently associated with higher body mass index, greater psychological distress, and greater alcohol dependence severity. Childhood trauma and poorer sleep quality were additionally associated with FA among treatment-seeking participants, whereas alcohol-related measures differed according to treatment status. Conclusions and Relevance: FA was common among adults with AUD and was associated with greater psychological, behavioral, and metabolic burden regardless of treatment-seeking status. These findings suggest that FA identifies a clinically meaningful subgroup of individuals with AUD who may benefit from more comprehensive assessment and integrated treatment approaches.

Background: Alcohol use disorder (AUD) is associated with altered gene expression across diverse cell types in reward-related brain regions, including the ventral tegmental area (VTA), which is rich in dopaminergic neurons. The VTA plays a central role in reward processing, learning, and memory; however, cell type-specific gene expression changes within the VTA remain uncharacterized. Methods: We applied single-nucleus RNA sequencing (snRNA-seq) to profile transcriptomic alterations associated with AUD in the VTA. Postmortem VTA samples from four individuals of European ancestry [two with AUD (one male, one female) and two matched controls (one male, one female)] were analyzed using the 10X Genomics Chromium Fixed RNA Profiling protocol. Differentially expressed genes (DEGs) were identified using Seurat, and enriched KEGG pathways was assessed by gene set enrichment analysis. Results: Nuclei were classified into six major cell types: astrocytes, endothelial cells, mature neurons, microglia, oligodendrocytes, and oligodendrocyte precursor cells (OPCs). At thresholds of P < 0.05 and |fold change| > 2.0, we identified 547 DEGs in astrocytes, 727 DEGs in endothelial cells, 715 DEGs in mature neurons, 421 DEGs in microglia, 263 DEGs in oligodendrocytes, and 432 DEGs in OPCs. DEGs across VTA cell types were enriched for pathways related to mitochondrial function, neurodegeneration, and synaptic signaling. Notably, DEGs in mature neurons were enriched for addiction-related pathways. Further subdivision of mature neurons into dopaminergic, GABAergic, glutamatergic, and unclassified subtypes revealed 526, 930, 896, and 569 DEGs, respectively. Neuronal DEGs indicate a convergence on mitochondrial/oxidative phosphorylation and neurodegeneration-related pathways across subtypes, whereas addiction- and synapse-related pathways show dopaminergic neuron-specific enrichment. Conclusions: This study provides the first cell type-resolved transcriptomic profiling of the human VTA, revealing AUD-associated gene expression alterations across neuronal, glial, and endothelial cells. The observed cell type-specific changes in synaptic plasticity and addiction-related genes offer new insights into molecular mechanisms underlying AUD pathophysiology.

BackgroundVariation in genes involved in ethanol metabolism has been shown to influence risk for alcohol dependence (AD) including protective loss of function alleles in ethanol metabolizing genes. We therefore hypothesized that people with severe AD would exhibit different patterns of rare functional variation in genes with strong prior evidence for influencing ethanol metabolism and response when compared to genes not meeting these criteria. ObjectiveLeverage a novel case only design and Whole Exome Sequencing (WES) of severe AD cases from the island of Ireland to quantify differences in functional variation between genes associated with ethanol metabolism and/or response and their matched control genes. MethodsFirst, three sets of ethanol related genes were identified including those a) involved in alcohol metabolism in humans b) showing altered expression in mouse brain after alcohol exposure, and altering ethanol behavioral responses in invertebrate models. These genes of interest (GOI) sets were matched to control gene sets using multivariate hierarchical clustering of gene-level summary features from gnomAD. Using WES data from 190 individuals with severe AD, GOI were compared to matched control genes using logistic regression to detect aggregate differences in abundance of loss of function, missense, and synonymous variants, respectively. ResultsThree non-independent sets of 10, 117, and 359 genes were queried against control gene sets of 139, 1522, and 3360 matched genes, respectively. Significant differences were not detected in the number of functional variants in the primary set of ethanol-metabolizing genes. In both the mouse expression and invertebrate sets, we observed an increased number of synonymous variants in GOI over matched control genes. Post-hoc simulations showed the estimated effects sizes observed are unlikely to be under-estimated. ConclusionThe proposed method demonstrates a computationally viable and statistically appropriate approach for genetic analysis of case-only data for hypothesized gene sets supported by empirical evidence.

BackgroundHabitual behavior and attentional bias are distinct cognitive processes that both contribute to inflexible behavior and are commonly observed in addiction. While animal studies provide strong evidence for an association between adolescent alcohol use and impairments in behavioral flexibility in adulthood, such a link in human research has not yet been explored. Moreover, since reduced flexible behavior serves as a risk factor for escalating alcohol intake, continued alcohol consumption use in adulthood may further exacerbate any deficits associated with adolescent drinking. MethodsWe used principal component analysis to create composite scores for adolescent and past year alcohol use, based on self-report measures from a healthy adult sample. Group differences in alcohol use were examined in relation to habitual responding (n=71) and attentional bias (n=44) toward non-drug reward cues, using two behavioral flexibility tasks. We used linear regression analyses to explore associations between past year alcohol use and behavioral flexibility outcomes in adults with histories of light versus heavy adolescent alcohol use. ResultsHeavy adolescent alcohol use was characterized by earlier drinking onset and higher binge-drinking frequency before age 18. Adults with a history of heavy adolescent alcohol use demonstrated significantly greater habitual responding compared to those with lighter use. Among this group, greater past year alcohol use was also associated with increased difficulty disengaging attention from non-drug reward cues. ConclusionsThese results indicate that adolescent and current alcohol use may differentially impact habitual responding and attentional bias towards non-drug reward cues. Notably, this is the first human study to explore both aspects of behavioral inflexibility in relation to different periods of alcohol use within the same adult sample.

BackgroundDopamine and serotonin are key regulators of reward sensitivity, yet their distinct roles in motivating natural (e.g., sucrose) versus drug (e.g., ethanol) rewards remain unclear. Understanding these mechanisms could help explain individual variability in reward processing relevant to substance use vulnerability. MethodsWe assessed reward sensitivity in dopamine transporter (DAT) and serotonin transporter (SERT) knockout (KO) rats using both home cage (two-bottle choice for sucrose and ethanol) and operant paradigms (Pavlovian and instrumental learning). ResultsDAT KO rats showed lower sucrose preference (-27% for 2%, -13% for 4%) and intake (-42% for 4%), diminished Pavlovian responding for sucrose (-68%), and slower acquisition of sucrose-taking behavior ([~]+30 days) compared to WT rats. DAT KO rats also showed reduced ethanol preference in the home cage (-16%) despite an unchanged intake. Furthermore, operant performed was markedly reduced operant performance after the sucrose-to-ethanol transition (-83%), with no increase in ethanol-taking following sucrose exposure (0% change), unlike WT controls (+41%). SERT KO rats presented reduced sucrose preference (-5%) and intake (-46%) for the 4% solution only. In addition, SERT KO rats also showed reduced Pavlovian sucrose responding (- 28%) and slower acquisition of sucrose-taking ([~]+30 days) but intact responding and learning for ethanol. In the home cage, they displayed lower ethanol preference (-35%) without significant change in operant ethanol performance. A modest overall increase in ethanol-taking was seen post-sucrose in both SERT KO and WT, but without genotype-specific effects. Conclusion and ImplicationsDAT deletion broadly impaired sensitivity for both natural sucrose and ethanol rewards, particularly under effortful or devalued conditions. In contrast, SERT deletion produced more selective impairments by disrupting sucrose operant responding and moderately reducing ethanol reward preference. These findings reveal distinct but overlapping roles of DAT and SERT in regulating reward sensitivity, with implications for understanding individual vulnerability to substance use.

Both prenatal alcohol exposure (PAE) and adolescent alcohol exposure (AAE) persistently impair executive function in humans and animal models. Executive function encompasses multiple interrelated domains including working memory, inhibitory control, and behavioral flexibility. We hypothesized that a developmental "double hit" of PAE and AAE would produce more severe behavioral deficits associated with these executive domains compared to alcohol-naive and single-exposed animals. We tested this hypothesis in rats by assessing disinhibition (low-light elevated plus maze; LL-EPM), behavioral flexibility (attentional set shift test; ASST), and working memory (spontaneous alternations in a T-maze); we also tested behavioral flexibility (ASST) in mice. Pregnant Sprague Dawley rats received water or 5 g/kg alcohol from gestational day (GD)13.5-GD20.5, and offspring received water or 5 g/kg alcohol on a 2-day-on, 2-day-off paradigm from postnatal day (PD)25 to PD54. Pregnant C57BL/6J mice received water or 4.5 g/kg alcohol from GD13.5-GD17.5, and offspring received water or 4.5 g/kg alcohol on a 2-day-on, 2-day-off paradigm from PD25 to PD42. Offspring underwent behavioral testing in young adulthood. Double hit rats showed more exploration in the LL-EPM than controls and fewer alternations in the T-maze than AAE-only rats, suggesting deficits in disinhibition and spatial working memory, respectively. Double hit rats and mice exhibited more errors and/or more trials to criterion in the ASST, indicative of decreased behavioral flexibility. Overall, double hit animals showed altered performance on tests related to executive function, suggesting that the combined exposure alters executive function in a manner distinct from single-exposure models.

Background Alcohol-associated injury is a leading cause of emergency department (ED) utilization in the United States and a clinically important driver of preventable morbidity across the adult lifespan. Prior surveillance research has characterized how the rate and severity of alcohol-associated injury vary by patient age, but whether the seasonal timing of injury risk is equally predictable across age groups (a question directly relevant to the timing of clinical screening intensification and public health intervention) has not been formally tested. Methods We conducted a retrospective surveillance analysis of 45,876 alcohol-associated ED visits among adults aged 18 years and older, identified from the National Electronic Injury Surveillance System (NEISS), 2019-2025 (weighted national estimate: 2,092,319 visits), using the structured Alcohol_Involved indicator introduced into NEISS case abstraction in 2019. Patients were stratified by sex and five age groups (18-24, 25-34, 35-49, 50-64, and [&ge;]65 years). Single-harmonic cosinor (Poisson) regression was used to estimate the seasonal peak day of injury risk (acrophase) for each stratum. To assess reliability, we performed leave-one-year-out jackknife resampling (seven iterations per group), case-resampling bootstrap confidence intervals (1,000 iterations), and likelihood-ratio tests of seasonal-phase interactions. Results Peak injury timing differed significantly across age groups (X^2 [8] = 2356.2, p < .0001). Adults aged 25-64 years showed a highly reproducible early-to-mid-July peak, with jackknife estimates shifting [&le;]14 days when any single study year was excluded. Adults aged [&ge;]65 years showed significant seasonal variation annually (all p < .0001, amplitude comparable to younger groups) but a pooled peak estimate that shifted by up to 100 days across jackknife iterations. Sex-stratified analyses revealed that this instability was driven entirely by females aged [&ge;]65 years (jackknife range: 332 days, peak consistently in late October through early January) rather than males aged [&ge;]65 (jackknife range: 31 days, peak consistently in early August). Hospital admission rates increased monotonically with age from 9.0% (18-24 years) to 31.8% ([&ge;]65 years). Conclusions Alcohol-associated injury follows a reproducible, calendar-stable summer seasonal pattern in adults aged 25-64 years. Among adults [&ge;]65 years, the previously reported temporal instability is concentrated in the female subgroup, whose seasonal injury risk does not converge on a fixed calendar window. These findings suggest that fixed-calendar prevention and screening strategies are well suited to working-age adults and older men, but older women may require a year-round, individually tailored approach. Keywords: Alcohol-related injury; Emergency department; Seasonality; Age factors; Sex differences; Injury surveillance; Cosinor analysis; Older adults

Any increase in alcohol use is associated with an increase in risk of illness and mortality and consequences of chronic alcohol use include cancer, hypertension, heart and liver disease, and Alcohol Use Disorder. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are effective anti-glycemic and weight-loss medications with a strong safety record. There is substantial preclinical evidence and mounting retrospective and prospective randomized controlled trial evidence that GLP-1RAs could be effective for reducing alcohol consumption. However, the mechanism by which GLP-1RAs reduce alcohol intake remains unclear. While medications that reduce alcohol intake such as naltrexone and acamprosate have central nervous system action, disulfiram reduces alcohol intake through peripheral mechanisms. Here, we test whether GLP- 1RAs alter alcohols peripheral pharmacokinetics as a potential mechanism of action for their alcohol intake suppressive effects. In this pilot study, twenty participants with obesity in the GLP-1RA or control group consumed a challenge dose of alcohol, and we measured breath alcohol (BrAC) and the subjective effects of alcohol. We observed a delayed rise in BrAC and subjective effects in the GLP-1RA group as compared to controls, that was not explained by nausea. These data provide preliminary evidence that GLP-1RAs could act through peripheral mechanisms to suppress alcohol intake.