Alcoholism: Clinical and Experimental Research

Objective To evaluate the association of early addiction consultation with withdrawal pharmacotherapy and complications in hospitalized patients with alcohol withdrawal. Methods Retrospective single-center cohort of adult hospitalizations with alcohol withdrawal (diagnosis code or CIWA-Ar [≥]10 within 24 hours) from July 2020 to January 2026. Exposure was an addiction consult service order within 24 hours of arrival, compared with no or later consultation. Primary outcomes were intensive care unit (ICU) transfer after the first 24 hours and delirium tremens or withdrawal seizure not present on admission. Process outcomes included phenobarbital and thiamine administration within 24 hours and benzodiazepine dose in the first 48 hours. Secondary outcomes included length of stay and 30-day death or return to hospital. Results Of 4,663 hospitalizations, 1,379 (29.6%) received early consultation. After adjustment, early consultation was associated with lower odds of ICU transfer (odds ratio [OR] 0.73; 95% CI 0.54-0.99) and fewer episodes of delirium tremens (risk difference -1.09 per 100; -1.45 to -0.73), with no significant difference in withdrawal seizure. Early consultation was associated with phenobarbital (OR 1.57; 1.32-1.86) and thiamine (OR 1.23; 1.07-1.41) within 24 hours, higher 48-hour lorazepam-equivalent dose (ratio of geometric means 1.44; 1.32-1.57), shorter stays (ratio 0.92; 0.88-0.97), and lower odds of 30-day death or return to hospital (OR 0.78; 0.66-0.91). Conclusions Early addiction consultation was associated with earlier, more intensive withdrawal pharmacotherapy, lower odds of ICU transfer, and fewer episodes of delirium tremens, although the complication associations were sensitive to cohort definition.

Chronic ethanol consumption produces long-lasting effects on the brain that contribute to persistent behavioral changes. This has been modeled in animals using the chronic intermittent ethanol (CIE) paradigm, which induces escalation of consumption and alterations in affective and cognitive behavior. While this model has been well characterized in male subjects, the effects of CIE in females and long-term effects that persist beyond the acute withdrawal remain relatively underexplored. Here, female C57BL/6J mice were exposed to four weeks of chronic intermittent ethanol (CIE) vapor to induce dependence. Following CIE, mice were evaluated for physiological tolerance to ethanol and alterations in anxiety-like behaviors and memory processing. Using the ethanol responsivity battery (ERB) assay to assess physiological tolerance, we found blunted responsiveness to the intoxicating effects of ethanol in the CIE-exposed females, indicating heightened ethanol tolerance that persists beyond the acute withdrawal phase. A cohort underwent behavioral testing following CIE to characterize changes in anxiety-like behavior, exploration, and memory across abstinence. In early abstinence (<5 days post-CIE), CIE-exposed females showed increased exploratory behavior compared with Air controls. After one week of abstinence, CIE-exposed females displayed impaired object recognition memory. CIE-exposed females also showed increased anxiety-like behavior at protracted abstinence time points, exhibiting hyponeophagia in the novelty-suppressed feeding test at 2 weeks post-CIE. In addition, following cued fear conditioning, we found reduced extinction recall at 4 weeks post-CIE. Together, this work indicates that chronic alcohol exposure leads to increased alcohol tolerance and distinct, persistent alterations in memory and anxiety-like behavior in female mice.

Background: Alcohol and cannabinoids are frequently used during pregnancy, however their combined effects on offspring outcomes are currently under-investigated. In this study, co-exposure was compared to single-drug and drug-free exposures for influences on adult alcohol-seeking and cannabinoid system proteomics. Methods: Pregnant C57BL/6J mice received ethanol vapor (ALC), CP-55,940 (0.75 mg/kg; CB), both (ALC+CB), or neither on gestational days 12-15. Beginning on Postnatal Day 200, male and female offspring underwent home-cage ethanol drinking (N=108) and operant self-administration, progressive-ratio, extinction, and reinstatement testing (N=96). CNR1 and CNRIP1 protein abundance was quantified in the medial prefrontal cortex (mPFC) and dorsomedial striatum (N=57) and compared to within-subject drinking behaviors. Results: Prenatal CB exposure increased cumulative home-cage ethanol intake, primarily in males. At 40% ethanol under progressive-ratio schedules, ALC+CB males consumed more than all other male groups, whereas all exposed female groups consumed more than controls. ALC+CB males also showed greater extinction responding than all other male groups and greater reinstatement intake relative to baseline than CON and ALC males. ALC+CB increased mPFC CNR1 in males relative to all other groups, whereas CB and ALC+CB reduced mPFC CNR1 in females. Higher mPFC CNR1 was associated with fixed-ratio and 40% progressive-ratio intake, extinction, and reinstatement exclusively in males. Conclusions: Prenatal co-exposure produced a persistent male phenotype of enhanced ethanol seeking that was distinct from either exposure alone and accompanied by elevated mPFC CNR1. This behavioral and molecular convergence justifies future investigations manipulating corticostriatal cannabinoid signaling to attenuate exposure-induced ethanol consumption in late adulthood.

Alcohol use disorders are heritable, and large-scale genome-wide association studies have recently identified novel genetic loci that are correlated with alcohol consumption and problematic alcohol use. One such gene is Slc39a8, which encodes the ion transporter ZIP8, responsible for cellular import of zinc and other metals. Slc39a8 is highly pleiotropic, and a common missense variant has been associated with decreased problematic alcohol use. Here, we used Slc39a8 heterozygous (HET) knockout mice and their wild type (WT) littermates to characterize the effects of reduced gene function on two models of voluntary alcohol consumption (drinking in the dark and intermittent access two-bottle choice), and anxiety- and depression-like behavior. We found that HET mice consumed less alcohol than WT in the intermittent access two-bottle choice procedure. No evidence was found for genotypic differences in baseline locomotor activity, anxiety-like, or depression-like behavior in the open field and forced swim tests. Slc39a8 mRNA expression and alcohol metabolism experiments confirmed decreased brain expression of Slc39a8 in HET mice and unchanged alcohol metabolism. Basal and post-alcohol measurement of zinc levels showed that HET mice after ethanol exposure had lower zinc concentrations in the liver and higher concentrations in blood than WT animals. Analysis of the spatial distribution of multiple trace metals in the brains of naive Slc39a8 HET and WT mice using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) showed region-specific genotypic differences in levels of zinc and iron. These results provide evidence for a direct role of Slc39a8 in ethanol consummatory behavior that does not appear to be due to metabolism, affective state, or locomotor activity. Moreover, we confirm that this animal model shows tissue- and brain region-specific alterations in zinc levels, highlighting potential mechanisms for future study.

In the KARE trial, 96 adults with severe alcohol use disorder, abstinent following detoxification, were randomised in a 2x2 factorial design to 3 weekly infusions of ketamine (0.8 mg/kg) or saline, each combined with mindfulness-based psychological support (PS) or alcohol psychoeducation (PE). We re-expressed the trial data on endpoints acceptable to regulators and compared the most and least intensive arms. Across pooled weeks 17-24, ketamine plus PS gave 78.5% versus 57.8% days abstinent (difference, 20.7 percentage points; P = .032); adjusted for baseline, the difference at weeks 21-24 was 26.9 percentage points (P = .011). At weeks 21-24, 50.0% versus 26.1% had no heavy drinking days (P = .127). Relative reductions in heavy drinking days were 55% in KARE, against 25%, -17%, 46% and 35% reported for naltrexone, exenatide, semaglutide and pemvidutide. These post hoc differences, measured 4 to 6 months after a 4 week course ended, are of magnitude similar to agents requiring continuous administration.

Importance: Preventing substance use disorder (SUD) is a top public health priority, but clinical practice currently lacks validated prognostic tools to identify risk before the onset of heavy use/problems. Objective: To determine whether models can predict SUD using genetic, behavioral, and environmental factors and to evaluate performance across substance types (alcohol, cannabis, tobacco), sex, and genetic similarity groups. Design: This prognostic study developed and validated a multi-domain risk model using data from four longitudinal cohorts (The National Longitudinal Study of Adolescent to Adult Health, Avon Longitudinal Study of Parents and Children, The Collaborative Study on the Genetics of Alcoholism, and FinnTwin12) with follow-up from early adolescence into young adulthood. Setting: Population-based and family-based samples from the United States, United Kingdom, and Finland. Participants: The analysis included participants with available genomic and behavioral data. The cohorts represented a spectrum of risk, ranging from nationally representative community samples to high-risk populations. Exposure(s) (for observational studies): Predictors included polygenic scores for substance use-related phenotypes and 10 established early-life behavioral and environmental risk factors. Main Outcome(s) and Measure(s): The outcomes were a diagnosis of moderate-to-severe SUD based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and positive and negative predictive value. Results: A total of 16,362 participants were included in the study (54.7% female; mean [SD] age 26.73 [3.36]). Genetic similarity group composition was 70.4% European, 16.8% African, 9.8% admixed American, 2.2% East Asian, and 0.7% South Asian. SUD prevalence was 22.0%. The integrated model achieved an AUC of 0.78 for predicting any SUD, with a sensitivity of 69% and a positive predictive value of 45%. Performance was comparable for specific substances (AUC range 0.74-0.82) and across genetic similarity groups (AUC range 0.61-0.82). The model demonstrated higher AUC in females compared with males. Conclusions and Relevance: Findings highlight the potential utility of an SUD prediction model to inform clinicians and patients about risk for developing a SUD.

Background: Deficits in inhibitory control are considered a central feature of alcohol use disorder (AUD), yet behavioral and neuroimaging findings have been inconsistent. One potential explanation is the marked heterogeneity of AUD, which encompasses multiple symptom dimensions that may differ in their underlying neurocognitive mechanisms. In this study, we investigated whether behavioral and neural markers of inhibitory control are associated with specific DSM-5 AUD symptom domains. Methods: A total of 589 participants (432 with non-treatment seeking AUD, 157 controls) completed a Stop-Signal Task (SST) during fMRI. Associations between DSM-5 symptom domains (impaired control over alcohol use, risky use, social problems, physical dependence) and SST performance, inhibition-related brain activation, and alcohol consumption were examined. Real-life drinking behavior was additionally assessed over 12 months using ecological momentary assessment (EMA). Results: Greater impaired control symptom severity was associated with poorer performance on go trials and diminished post-error slowing during SST. At the neural level, higher impaired control symptom severity was associated with reduced activation across fronto-insular, parietal, cingulate, supplementary motor, and cerebellar regions. In contrast, other symptom domains showed little to no associations with inhibition-related behavioral or neural measures. Higher impaired control symptom severity was associated with greater alcohol consumption across questionnaire-based and EMA-based assessments. Conclusions: In this large cohort, altered behavioral performance and recruitment of inhibition-related brain regions in the SST was selectively linked to impaired control symptoms. These findings highlight the importance of symptom-based approaches for understanding heterogeneity in addiction and may inform the development of more targeted interventions.

Fetal alcohol spectrum disorders (FASD) are caused by prenatal alcohol exposure (PAE), which leads to developmental defects during embryogenesis. Angiogenesis is one facet of development that is heavily dysregulated during PAE and where such impairment is poorly understood. Here we found that expression levels of focal adhesion molecules Tensin 1 (Tns1) and Tensin 2 (Tns2) were significantly reduced by alcohol exposure in brain microvascular endothelial cells (BMVECs). We also found that miR-150-5p, which we previously found was increased by PAE, regulates the expression of Tns1 and Tns2. Dual-luciferase assays demonstrated direct binding of miR-150-5p to the 3UTRs of Tns1 and Tns2. Additionally, we utilized sprouting angiogenesis bead assays to evaluate endothelial cell sprouting in response to ethanol (EtOH) treatment and following Tns1 and/or Tns2 overexpression as well as miR-150-5p modulation. Tns1 and Tns2 rescued both EtOH- and miR-150-5p-mediated deficits in sprouting angiogenesis. Overall, we found that miR-150-5p negatively regulates Tns1 and Tns2 in BMVECs and that augmenting Tns1 and Tns2 expression may reverse the negative effects of EtOH, and subsequent miR-150-5p elevation, thus improving endothelial cell sprouting during cerebrovascular development.

Background: Social difficulties in alcohol use disorder (AUD) have been linked to alterations in social cognition, including increased egocentric bias. Psychedelics such as psilocybin have been proposed to modulate self-related processing, but their effects on specific socio-cognitive mechanisms remain unclear. Methods: In this randomized controlled pilot study, recently detoxified individuals with AUD with persistent depressive symptoms completed a visual perspective-taking task before and after a psilocybin session (25 mg dose vs active placebo 1 mg psilocybin). Results: The 25 mg psilocybin group showed a significant reduction in egocentric bias and egocentric superiority on reaction times, with no effect on altercentric bias nor on accuracy. Between-group comparisons confirmed greater reductions in the high-dose relative to the low-dose group. The high-dose group reported more intense subjective psychedelic experiences, and greater subjective intensity was associated with lower egocentric superiority in accuracy. Conclusions: These findings provide preliminary evidence that psilocybin may selectively reduce egocentric interference in individuals with AUD, suggesting a decrease in egocentricity rather than enhanced sensitivity to others. Although replication in larger samples is needed, reduced egocentricity may represent one mechanism through which psilocybin influences social cognition in AUD. Clinical trial registration: ClinicalTrials.gov, https://clinicaltrials.gov/study/NCT06235411, NCT06235411.

Genome-wide association studies (GWAS) have identified numerous loci associated with substance use disorders (SUDs). To connect common genetic variation to cell type- and region-specific gene expression and chromatin accessibility, we examined the enrichment of genetic liability for several SUDs (alcohol, cannabis, tobacco, and opioid use disorders) and substance consumption phenotypes (drinks per week, cannabis ever-use, and cigarettes per day) in available single-nucleus RNAseq data spanning 10 brain regions and snATACseq data spanning 42 brain regions. Significant cell-type enrichment after multiple testing corrections was observed only for drinks per week and tobacco use disorder in the snRNAseq data and for cannabis use disorder and problematic alcohol use in snATACseq data. Across both transcriptomic and chromatin accessibility annotations, enrichment patterns were concentrated in excitatory neuronal populations, particularly upper layer intratelencephalic neurons, amygdala excitatory neurons, and regionally resolved striatal medium spiny neuron subtypes. Drinks per week, problematic alcohol use, and cannabis use disorder showed enrichment values that were significantly correlated within cell-type across snRNAseq and snATACseq, suggesting convergent biological signals across independent single-nucleus modalities. These findings implicate chromatin-mediated expression differences in specific excitatory neuronal populations as potential mediators of SUD genetic liability and highlight the value of integrating transcriptomic and chromatin accessibility data for characterising the neurobiology of addiction.

Alcohol use disorder is associated with persistent neuroadaptations and cognitive impairments, particularly during withdrawal, yet the temporal dynamics and interactions between these processes remain poorly understood. In the present study, we investigated time-dependent alterations in the oxytocin receptor (OTR), -opioid receptor (MOPr), metabotropic glutamate receptor 5 (mGlu5R), and translocator protein (TSPO) following chronic ethanol exposure and withdrawal, and their relationship to behavioral impairments. Male C57BL/6J mice were exposed to a 10-day escalating-dose ethanol liquid diet paradigm followed by 1, 4, or 7 days of withdrawal. Motor coordination and recognition memory were assessed using rotarod and novel object recognition tests, and receptor binding was quantified using autoradiography across multiple brain regions. Chronic ethanol exposure induced motor deficits that persisted during early withdrawal, whereas recognition memory impairments emerged after 7 days of withdrawal. Ethanol exposure and withdrawal produced region- and time-dependent alterations across all systems examined, with increased OTR binding in septal regions and transient reductions in basomedial amygdala OTR binding during intermediate withdrawal that normalized following prolonged withdrawal, transient increases in MOPr binding in striatal regions at 4 days of withdrawal, increased mGlu5R binding in the nucleus accumbens core, basolateral amygdala, and hippocampus, and early transient increases in TSPO binding indicative of neuroimmune activation. Notably, mGlu5R binding in the caudate-putamen and amygdala was associated with recognition memory deficits in a withdrawal stage-dependent manner. Bioinformatic analysis of human postmortem hippocampal transcriptomic datasets from individuals with alcohol use disorder revealed no consistent changes in GRM5 expression, suggesting that mGlu5R dysregulation may be driven by post-transcriptional mechanisms. These findings demonstrate that ethanol withdrawal is characterized by temporally distinct neuroadaptations across multiple systems and identify mGlu5R as a key correlate of withdrawal-associated memory impairment, highlighting its potential as a translational therapeutic target.

Circadian clock genes in the striatum modulate alcohol drinking behavior in female mice, but the underlying synaptic mechanisms remain unknown. Medium spiny neurons (MSNs) of the striatum express D1- or D2-type dopamine receptors, which are differentially modulated by alcohol. Here we used whole-cell patch-clamp recordings to examine how deletion of the clock gene Bmal1 affects spontaneous excitatory postsynaptic currents (sEPSCs) in electrophysiologically identified D1 and D2 neurons of the female mouse dorsomedial striatum (DMS). Prior intermittent access to alcohol increased sEPSC amplitude in putative D1 neurons of wildtype mice without affecting sEPSC frequency, and this increase was accompanied by greater dendritic branching and complexity in biocytin-filled D1 MSNs. Bmal1 knockout had the opposite effect in D1 neurons, reducing sEPSC amplitude in both alcohol-exposed and alcohol-naive animals. In D2 neurons, alcohol produced only a non-significant trend toward increased sEPSC amplitude in wildtype mice, but a significant increase in Bmal1 knockout mice. Thus, local disruption of Bmal1 appears to block the alcohol-induced enhancement of sEPSCs in D1 neurons while unmasking a similar enhancement in D2 neurons. These findings may help explain how Bmal1 deletion in the DMS reduces alcohol consumption in female mice.

Chronic heavy alcohol use shifts brain metabolism from glucose toward acetate utilization. Sudden decreases in acetate following alcohol cessation in individuals with alcohol use disorder (AUD) may create an energetic imbalance that contributes to craving and withdrawal. A recent randomized study found that, compared with a standard American (SA) diet, a ketogenic diet (KD) during alcohol detoxification reduced withdrawal severity and craving and increased ketones and glutamate in the dorsal anterior cingulate cortex. These findings suggest that ketones may support metabolic adaptation during alcohol withdrawal, but the effects of altered brain metabolism on neural dynamics and alcohol cue reactivity remain unknown. Here, we used a control theoretic approach to test whether shifts in cerebral energy substrate utilization influence large-scale network dynamics through altered information flow. We analyzed fMRI cue-reactivity scans collected after one, two, and three weeks of inpatient treatment during presentation of alcohol, food, and neutral cues. Whole-brain effective connectivity was estimated using Shannon transfer entropy applied to whole brain atlas-aligned fMRI time series. Assuming neural activity flow along effective connections, we identified distinct shifts in the state-transition landscape in participants receiving the KD compared with the SA diet. Increases in serum {beta}-hydroxybutyrate (BHB) were associated with changes in state-transition landscape organization, which were in turn associated with reduced cue-induced alcohol craving. These findings link metabolic adaptation to large-scale neural dynamics and clinically relevant behavior and suggest that cerebral energy substrate availability may shape behavior by altering the organization of large-scale neural dynamics.

Background: ADHD is characterized by inattention and impulsivity. Stimulants such as amphetamine are the first line treatments for ADHD. Amphetamine (AMPH) works by increasing extracellular levels of dopamine and noradrenaline. Such stimulants are used to test predictive validity of animal tasks, where it has been reported that amphetamine improves rat 5-CSRTT accuracy when the session length is increased to 250 trials. This improvement in accuracy was observed later in the session as control performance declined. Proving that amphetamine can improve 5C-CPT task performance adds to the predictive validity of the task. No previous works has demonstrated the pro-attentional effects of amphetamine on sustained attention in rat 5C-CPT. We have previously shown that pharmacological manipulations of dopaminergic system improve waiting impulsivity in a rate dependent manner and the importance of analysing the data using Oldham method. The present study extends this work to investigate the effect of amphetamine on attentional processes. Objective: to investigate effects of amphetamine on attentional processes as measured by 5C-CPT task using correlational analysis and group performance. Methods: Trained female Lister hooded rats were tested with AMPH (0.1, 0.2 and 0.4 mg/kg) under reduced stimulus duration schedule (0.25,0.5,1,1.5 and 2s SD) over normal length session (120 trials). Correlational analysis (Oldham method) was used to understand the relationship between baseline performance measures and the change following administration of AMPH. Results: The highest dose of AMPH impaired attentional performance in the 5C-CPT under reduced SD challenge (0.5s,1s,1.5s and 2s). This impairment was due to increase in FAR. Previous studies in 5-CSRTT suggest that reducing the SD increases attentional demand in the form of reducing accuracy without affecting waiting impulsivity. However, the 5-CSRTT does not include non-target trials, therefore, it cannot be used to measure sustained attention (SI) and responsivity index. The 5C-CPT requires greater attentional resources than the 5-CSRTT.This study is the first to report that reducing the SD changes responsivity index (bias) rather than measures of sustained attention (sensitivity index) in the 5C-CPT. Control sensitivity index did not change until the SD was reduced to less than 0.5s and this change was due to a change in baseline responsivity index (bias). Performance under each reduced SD revealed that the highest dose of AMPH (0.4 mg/kg) showed a tendency toward reducing sensitivity index at 0.5, 1.0 and 1.5s SDs. Under 1.0s SD, the highest dose of AMPH changed sustained attention (SI, HR and FAR) and omission in a rate-dependent manner without changing responsivity index. Performance across the session revealed that the impairment in sustained attention was observed at the beginning of the session. In the third trial block, Oldham method revealed an inverse relationship between baseline accuracy and the change following administration of 0.2 mg/kg AMPH, indicative of a rate-dependent effect. Conclusions: This study successfully demonstrates rate-dependent effects of AMPH on measures of attentional performance in the 5C-CPT. This experiment also demonstrates that responsivity index is sensitive to reduced SD challenge. To our knowledge this is the first study to report the presence of a direct relationship between baseline sustained attention and magnitude of improvement following administration of 0.4 mg/kg AMPH and an inverse relationship between baseline accuracy and the change following administration of 0.2 mg/kg AMPH in 5C-CPT task. Future studies should test lower doses of amphetamine (0.05 and 0.1 mg/kg) over extended session length (250 trials) to reveal the pro-attentional effects of this drug on 5C-CPT performance measures.

Pavlovian conditioned stimuli can compromise goal-directed behavior, particularly when they conflict with the required instrumental response. Previous research linked an increased impact of such Pavlovian-to-instrumental transfer (PIT) interference to risky drinking and alcohol dependence. However, it remained unclear whether the observed behavioral and neural alterations generalize to the substantially larger population of non-treatment-seeking individuals with predominantly mild-to-moderate alcohol use disorder (AUD) and to other substances like nicotine. We therefore studied 200 participants from the general population who were stratified by AUD and smoking status before completing a single-lever PIT task during functional imaging. PIT interference was measured as the difference in error rates between incongruent PIT trials, characterized by conflicts of Pavlovian and instrumental stimuli, and congruent trials. Associations with AUD and smoking status, as well as dimensional associations of behavioral PIT interference and neural responses to PIT conflicts with substance-related measures, were examined. As expected, participants with AUD showed greater PIT interference and reduced conflict-related activation in the lateral prefrontal, dorsomedial prefrontal, and anterior cingulate cortex than participants without AUD. The magnitude of these alterations also correlated with higher AUD severity and alcohol consumption, while being independent of smoking status and other smoking-related measures. These findings suggest that enhanced PIT interference generalizes to the broader AUD population but may not extend to other substances like nicotine. They further implicate a reduced recruitment of prefrontal control networks during PIT conflicts as a potential mechanism underlying enhanced PIT interference in AUD and its association with clinically relevant outcome measures.

Background: Risk of recurrent overdose is elevated following non-fatal overdose (NFOD) survival; timely interventions may reduce this risk. The specific role of mental health care in reducing recurrence is relatively underexplored, and post-overdose care has seldom been examined for sex differences. This study examined sex differences in the association between mental health-related primary care contacts following NFOD and overdose recurrence risk among people in British Columbia (BC) with a documented depression diagnosis history. Methods: This was a nested case-control study using linked administrative health data from the Provincial Health Services Authority Platform for Analytics and Data. The source cohort (n=7,022) comprised BC residents with a history of a documented depression diagnosis between 2010-2014 and at least one NFOD between 2015-2024. Cases experienced a recurrent overdose within one year of their index overdose; controls were selected using incidence density sampling. Exposures were the presence and number of mental health related primary care contacts in the 30- or 90-day window following the index overdose. Conditional logistic regression models were used to estimate adjusted incidence rate ratios (aIRRs) and confidence intervals (CI), overall and by sex. Secondary analyses were conducted using psychiatrist contacts. Results: Mental-health related primary care contact rates were low, with only 16.3% and 28.1% of the cohort with any contact within 30 and 90 days, respectively. Mental health-related primary care contacts were more strongly associated with reduced recurrence risk in the 30-day window (any contact aIRR: 0.57 [CI: 0.46-0.71]) than in the 90-day window (aIRR: 0.78 [CI: 0.65-0.94]). Any contact within 30 days was more strongly associated with lower recurrence risk among males (aIRR: 0.53 [CI: 0.39-0.72]) than among females (aIRR: 0.67 [CI: 0.50-0.91]), whereas associations between the number of contacts and recurrence risk were similar for males and females. Any psychiatrist contact within 30 days was more strongly associated with lower recurrence risk among females (aIRR: 0.50 [CI: 0.34-0.73]) than males (aIRR: 0.70 [0.52-0.95]). Discussion: Mental health-related care contacts shortly following NFOD were associated with lower overdose recurrence risk among people with a documented depression diagnosis history, with modest sex differences that varied by provider type. Low rates of contacts overall suggest gaps in access to care following NFOD, particularly among males. Further research on sex differences in post-overdose care are warranted.

Alcohol consumption is an established risk factor for breast cancer, with a particularly strong association with estrogen receptor-positive (ER+) disease. Although the estrogenic activity of alcohol is well recognized, how alcohol-induced ER signaling is coupled to growth factor receptor pathways that promote tumor cell growth and progression remains incompletely understood. Here, we identify neuregulin-1 (NRG1) as a functional mediator, linking alcohol-induced ER activity to ErbB3 receptor tyrosine kinase signaling in ER+ breast cancer cells. Under estrogen-depleted conditions, alcohol induced proliferation, clonogenic growth, and S-phase progression in MCF-7 and T47D cells. Alcohol concurrently increased ER phosphorylation and transcriptional activity, including enhanced ER occupancy at the endogenous TFF1/pS2 regulatory region, and activated ErbB3 and downstream Akt, ERK, and p38 signaling. Notably, alcohol induced NRG1 expression in both cell lines. Pharmacological inhibition of ER signaling with ICI 182,780 (fulvestrant) substantially attenuated NRG1 induction, ErbB3/RTK activation, and alcohol-promoted growth, indicating that NRG1 induction and engagement of RTK signaling are strongly dependent on functional ER signaling. Conversely, shRNA-mediated NRG1 depletion suppressed alcohol-induced proliferation, clonogenic growth, and cell-cycle progression and markedly reduced alcohol-induced migratory and invasive phenotypes. NRG1 depletion also attenuated ErbB3/Akt/ERK signaling while reducing ER activation and ERE-dependent transcription, demonstrating a functional contribution of NRG1 to both arms of the signaling response. Together, these findings support a reciprocal ER-NRG1-ErbB3 signaling circuit in which alcohol-induced ER activity promotes NRG1 expression, while NRG1-dependent ErbB3 signaling reinforces ER activity and tumor-promoting phenotypes. Our study identifies NRG1 as a previously unrecognized molecular link between the estrogenic activity of alcohol and growth factor receptor signaling and provides a mechanistic framework for understanding alcohol-associated promotion of ER+ breast cancer.

Background Cocaine use disorder (CUD) is estimated to be 50% heritable, yet few genetic variants have been robustly associated with risk. During January 2021 to June 2024, cocaine was involved in 30% of U.S. overdose deaths. Identifying genetic contributors to CUD could inform diagnostics and treatments. The missing heritability may stem from small sample sizes, models that inadequately account for small-effect common variants, and the exclusion of large-effect structural variants like copy number changes. Epistasis likely contributes but remains challenging to detect genome-wide. Results We focused on epistasis and haplotypes rather than individual SNPs by applying the custom correlation coefficient in BlocBuster to construct allele networks from eQTL SNPs. Testing these regulatory haplotype networks for association with cocaine use in 7,826 individuals with opioid use disorder identified 12 significant associations across two ancestries. For one haplotype, raw genotyping array intensity data revealed a copy number increase at the CYP2D6 locus in individuals of European ancestry. In a subcohort of individuals who co-use cocaine and heroin (i.e., speedball), two haplotypes were also significantly associated with HIV infection. One of these involved GPR75, whose ligand, CCL5 (RANTES), is shared with CCR5, a coreceptor for HIV entry. Conclusions Our findings, integrated with long-read human pan-genomes, support a model in which non-functional copies of CYP2D6 disrupt dopaminergic, glutamatergic, and kynurenine pathways in the brain, contributing to cocaine use severity. The association of additional haplotypes with HIV status in speedball users highlights the genetic contribution to comorbid risk in high-exposure populations.

Chronic alcohol consumption is associated with increased breast cancer risk; however, the long-term effects of alcohol exposure on DNA damage response (DDR) signaling and therapeutic vulnerability in breast epithelial cells remain incompletely understood. In the present study, we established a chronic alcohol exposure model using immortalized human breast epithelial MCF-10A cells to investigate persistent alterations in DNA damage signaling and sensitivity to poly (ADP-ribose) polymerase (PARP) inhibition. MCF-10A cells that chronically exposed to 0.2% alcohol for 20 weeks and then withdrew alcohol treatment for 4 weeks still retained elevated {gamma}H2AX levels and sustained activation of ATM/ATR-associated DDR pathways. Chronic alcohol-exposed cells also exhibited increased sensitivity to the PARP inhibitors olaparib and veliparib, as demonstrated by reduced cell viability, decreased clonogenic survival, and enhanced apoptosis. Mechanistically, olaparib induced greater G2/M checkpoint activation and replication-associated DNA damage in chronic alcohol-exposed cells compared with control cells. In addition, chronic alcohol exposure increased PARP expression and enhanced activation of DDR signaling following PARP inhibition. These findings demonstrate that chronic alcohol exposure induces persistent DNA repair stress and sensitizes breast epithelial cells to PARP inhibition. Our study suggests that chronic alcohol-associated genomic stress may create potential vulnerability to PARP inhibition.

Background We aimed to characterize substance use patterns, and their correlates, among adults with and without HIV at two healthcare facilities in Cape Town, South Africa. Methods We recruited adults with and without HIV from two primary healthcare facilities. We assessed alcohol use with the AUDIT-C and other substance use with the WHO-ASSIST questionnaires. We classified participants with no lifetime drug use and no or low-risk alcohol use as "low risk" and fitted latent class models among remaining participants to identify additional substance use patterns. We used multinomial logistic regression to examine factors associated with substance use patterns. Results Among 602 participants, 265 (44.0%) were "low risk". Latent class analysis among the remaining 337 identified three patterns: "higher-risk alcohol use" (N=168; 27.9%), "cannabis use" (universal cannabis use with mixed alcohol risk; N=114; 18.9%), and "mixed illicit drug use" (predominantly no or low-risk alcohol use with use of multiple drugs; N=55; 9.1%). Participants younger than 45 years were less likely to be in the low-risk group. Male sex was associated with lower probability of the low-risk group and higher probability of the higher-risk alcohol use and cannabis use classes. HIV was associated with higher probability of higher-risk alcohol use. One facility had a substantially higher probability of mixed illicit drug use. Conclusions We identified distinct higher-risk substance use profiles that varied strongly by age, sex, and facility. These findings support integrating alcohol and substance use screening and management into primary care and tailoring responses to local substance use patterns.