Alcohol�s Negative Emotional Side: The Role of Stress Neurobiology in Alcohol Use Disorder

Subgroups of anxiety and depression trajectories during early abstinence in alcohol use disorder

BACKGROUND

Symptoms of anxiety and depression are common during early abstinence and can precipitate relapse. Previous studies show that, on average, anxiety and depression symptoms are typically elevated at treatment intake and decline rapidly during the first month. However, alcohol use disorder (AUD) is clinically heterogeneous, and it remains unknown whether there are distinct subgroups in the trajectories of anxiety and depression symptoms or whether all individuals show the characteristic decline.

METHODS

This study aimed to identify and characterize anxiety and depression trajectories in a large sample (n = 1005) of individuals with AUD during early abstinence. Deidentified electronic medical record data were obtained from a community substance use treatment program. Anxiety and depression symptoms were assessed weekly using the GAD-7 and PHQ-9 scales, respectively. Latent growth curve analyses were used to identify subgroups.

RESULTS

Three subgroups were identified for both anxiety and depression trajectories: low, high, and sustained. The low trajectory subgroup comprised the majority of individuals (73% for anxiety, 70% for depression) and showed rapid symptom reduction. The high trajectory symptom subgroup (22% for anxiety, 24% for depression) showed a slower decrease in symptoms. In comparison, the sustained trajectory symptom subgroup (5% for anxiety, 6% for depression) maintained high reported symptoms throughout treatment. The three trajectory subgroups differed in age, sex, co-occurring mental health and substance use disorders, and PTSD symptom severity scores.

CONCLUSION

These findings provide strong evidence for subtypes based on anxiety and depression symptom trajectories in early abstinence. Early identification of individuals in the sustained trajectory subgroup could improve treatment outcomes and reduce relapse risk.

Salivary cortisol trajectories among inpatients undergoing substance use disorder treatment: A prospective repeated-measures study

BACKGROUND

A growing body of research among inpatients with substance use disorders (SUD) suggests a link between cortisol levels and treatment outcomes. However, there is limited insight into the pattern of cortisol level during an inpatient SUD treatment stay.

AIM

The aim was to investigate changes in salivary cortisol levels during 8 weeks of an inpatient SUD treatment stay, and to determine whether the primary SUD diagnosis exerted a distinct effect on cortisol level trajectories.

METHODS

We employed a prospective repeated-measures design and followed a cohort of patients with various SUD diagnoses. Salivary cortisol samples were collected at four time points during the first 8 weeks of the treatment stay (t1: week 2 (baseline); t2: week 4; t3: week 6; and t4: week 8). We assessed basal cortisol concentration by calculating the area under the curve with respect to ground (AUCG), which represents total daily cortisol output. Associations were determined using Linear mixed model analyses (LMMs).

RESULTS

The analytic sample comprised 173 patients. The full LMM model, including covariates (i.e. polysubstance disorder, age, gender, treatment history, treatment unit, mental distress) revealed that cortisol levels decreased from t1 to t2 (β = -7.218; 95 % CI: -11.126 to -3.310; p < 0.001) and stabilized thereafter. Patients with opioid use disorders (OUD) had lower cortisol level trajectories than patients with stimulant use disorders (β=-20.357; 95 % CI: -29.394 to -11.319; p < 0.001), while patients treated in the long-term unit showed elevated cortisol trajectories relative to those in the short-term unit (β=6.650; 95 % CI: 0.072-13.229; p = 0.048).

CONCLUSION

This study showed a decline in cortisol levels during the first 4 weeks of SUD inpatient treatment, followed by stabilization. Patients with stimulant use disorders had higher cortisol levels over time than those with OUD. Further research should explore the clinical implications of the current findings. In particular, greater insight into the moderating effects of polysubstance disorders on cortisol levels may contribute to the development of individual tailored treatment approaches.

Gut Microbiome-Liver-Brain axis in Alcohol Use Disorder. The role of gut dysbiosis and stress in alcohol-related cognitive impairment progression: possible therapeutic approaches

The Gut Microbiome-Liver-Brain Axis is a relatively novel construct with promising potential to enhance our understanding of Alcohol Use Disorder (AUD), and its therapeutic approaches. Significant alterations in the gut microbiome occur in AUD even before any other systemic signs or symptoms manifest. Prolonged and inappropriate alcohol consumption, by affecting the gut microbiota and gut mucosa permeability, is thought to contribute to the development of behavioral and cognitive impairments, leading to Alcohol-Related Liver Disorders and potentially progressing into alcoholic cirrhosis, which is often associated with severe cognitive impairment related to neurodegeneration, such as hepatic encephalopathy and alcoholic dementia. The critical role of the gut microbiota is further supported by the efficacy of FDA-approved treatments for hepatic encephalopathy in alcoholic cirrhosis (i.e., lactulose and rifaximin). To stimulate new research, we hypothesize that interactions between a maladaptive stress response and a constitutional predisposition to neurodegeneration underlie the progression of AUD to conditions of Alcohol-Related Clinical Concerns with severe cognitive impairment, which represent a significant and costly burden to society. Early identification of AUD individuals at risk for developing these conditions could help to prioritize integrated therapeutic interventions targeting different substrates of the Gut Microbiome-Liver-Brain axis. Specifically, addiction medications, microbiome modulators, stress-reducing interventions, and, possibly soon, novel agents that reduce hepatic steatosis/fibrosis will be discussed in the context of digitally supported integrated therapeutic approaches. The explicit goal of this AUD treatment performed on the early stage of the disorder would be to reduce the transition from AUD to those conditions of Alcohol-Related Common Clinical Concerns associated with severe cognitive impairment, a strategy recommended for most neurological neurodegenerative disorders.

History of Alcohol Use Disorder and Housing Instability as Predictors of Fatigue and Mental Health Problems During the COVID-19 Pandemic

Mental health and alcohol problems are significant public health concerns amid the COVID-19 pandemic. Housing instability and symptoms of fatigue are understudied aspects of the pandemic. This study examined history of Alcohol Use Disorder (AUD), history of COVID-19 infection, and housing instability as correlates of fatigue, anxiety, and depression symptoms. Data were drawn from 250 adults enrolled in an online survey within the NIAAA COVID-19 Pandemic Impact on Alcohol Study in between April 6 and June 2 of 2022. Participants completed self-report measures of housing stability, fatigue, and mental health symptoms. Multivariable analyses controlling for age, sex, race, ethnicity, and household income were conducted. Individuals with a history of AUD reported higher mental fatigue, anxiety symptoms, and depressive symptoms when compared to those with no history of AUD. Individuals with "other" housing arrangements (not renting or owning) reported higher mental fatigue, pandemic fatigue, anxiety symptoms, and depressive symptoms relative to homeowners. Individuals who worried about not having a place to live in the past 6 months reported higher physical fatigue, mental fatigue, anxiety symptoms, and depressive symptoms when compared to individuals without housing worry. History of COVID-19 infection was neither associated with mental health nor fatigue symptoms. Housing instability, as captured by housing worry and having "other" housing arrangements, was associated with greater fatigue and mental health problems, even after controlling for household income. Housing instability uniquely contributed to mental health symptoms, warranting further research and targeted prevention and intervention efforts.

A stress-activated mid-insula to BNST pathway regulates susceptibility to abstinence-induced negative affect in female mice

Stress is central to many neuropsychiatric conditions, including alcohol use disorder (AUD). Stress influences the initiation and continued use of alcohol, the progression to AUD, and relapse. Identifying the neurocircuits activated during stress, and individual variability in these responses is critical for developing new treatment targets for AUD, particularly to mitigate stress-induced relapse. Using a longitudinal approach, this study examined the relationship between sub-chronic stress exposure and negative affect during protracted abstinence following chronic ethanol exposure. Sub-chronic restraint stress heightened negative affect-like behavior in protracted abstinence. Interestingly, this was driven by a subset of "stress-susceptible" female mice. We examined the mid-insula, a hub in the brain's salience network, as a driver of this effect, given its role in emotional regulation and links to alcohol craving, consumption, and abstinence-induced negative affect. Mid-insula GCaMP fiber photometry revealed that GCaMP activity during stress exposure was positively correlated with activity during the novelty-suppressed feeding test (NSFT) two weeks into abstinence. A distinct subset of mice exhibited increasing activity during the consummatory phase, implicating the mid-insula as a neural basis for heightened negative affect in abstinence. Chemogenetic inhibition of mid-insula neurons projecting to the dorsal BNST during stress disrupted the emergence of stress susceptibility, highlighting this circuit as a key determinant of susceptibility to abstinence-induced negative affect. These outcomes were female-specific, addressing a critical gap in understanding AUD risk in women. Furthermore, female mice exhibited higher struggling behavior during stress than males. However, this effect was blocked by chemogenetic inhibition of the insula-BNST pathway during stress. By linking pre-alcohol stress response with abstinence outcomes, this work positions the insula-BNST pathway as a potential AUD circuit activity biomarker and therapeutic target.

HCV Treatment Outcomes in PWID: Impact of Addiction History on SVR12

People who inject drugs (PWIDs) experience high rates of hepatitis C virus (HCV) infection, primarily due to needle sharing and limited healthcare access, resulting in a disproportionate disease burden within this population. This prospective study evaluated treatment outcomes in 432 adult patients with chronic hepatitis C (CHC) treated with direct-acting antivirals (DAAs) at the University Clinical Center of Serbia. Patients were categorized into two groups based on a history of drug addiction: PWIDs (163, 37.7%) and non-PWIDs (269, 62.3%). The PWID group was further categorized into subpopulations of problematic PWIDs (39, 23.9%), ex-PWIDs (124, 76.1%), and PWIDs on OST (96, 58.9%). The PWID group demonstrated significantly lower treatment adherence, with an intention-to-treat (ITT) rate of 82.8%, compared to 96.3% in the control group (p < 0.001). In contrast, no significant differences were observed in per-protocol (PP) outcomes between the two groups. Additionally, PWIDs were significantly younger (p < 0.001) and had higher rates of psychiatric disorders (p < 0.001), alcohol abuse (p < 0.001), and HCV genotype 1a (p < 0.001). Advanced fibrosis was predictor of PP treatment failure among PWIDs, while mood disorders and alcohol use disorder were associated with interruptions before the scheduled completion time. For non-PWIDs, older age and advanced fibrosis emerged as key predictors of PP treatment failure. The loss to follow-up was most commonly observed in the problematic PWID subgroup (p = 0.001). These findings highlight the importance of addressing barriers in PWIDs through integrated care strategies that concurrently manage addiction and HCV.

Re-evaluating our focus in addiction: emotional dysregulation is a critical driver of relapse to drug use

Most addiction research has focused on reward- and impulsivity-related neurocircuitry. However, the impact of the withdrawal/negative affect stage in the addiction cycle has been somewhat overlooked, despite it being commonly evident in the clinic. This stage crucially drives negative reinforcement of repeated drug use and relapse, yet less is known about its neural underpinnings. How negative emotional processing is dysregulated in substance dependence is incompletely understood and may manifest differentially across the types of substances. In turn, the regions involved in negative emotional processing may show different patterns of dysregulation. Understanding how neurocircuitry involved in negative states differs across various substances may help inform new targets for treatments. Following a comprehensive literature search of studies examining negative emotional processing in substance dependence, a quantitative approach was deemed inappropriate. Instead, we employed a narrative approach to exploring neural responses to tasks involving emotional processing in alcohol, cocaine, opioid and cannabis dependence. Regions that were found to be dysregulated included the amygdala, insula, anterior cingulate, and medial prefrontal cortex. However, patterns of reactivity differed across alcohol, cocaine, opioid and cannabis dependence. Brain activation in alcohol dependence broadly appeared blunted in response to negative affective stimuli and emotional faces, whilst conversely appeared heightened in cocaine dependence. In opioid dependence, the amygdala was consistently implicated, whilst the insula, anterior cingulate, and medial prefrontal cortex were implicated in cannabis dependence. However, there was wide variability amongst the studies, with very few studies investigating opioid and cannabis dependence. These findings suggest emotional dysregulation varies according to the type of substance dependence. However, the variability in findings and lack of studies highlights the need for more research in this area. Further characterisation of emotional dysregulation in substance dependence will enable identification of treatment targets. More targeted treatments that modulate negative emotional processing could substantially improve outcomes by aiding relapse prevention.

Sex-specific differences in the association between triglyceride glucose index and carotid plaque in a cardiovascular high-risk population: a cross-sectional study based on a Chinese community-dwelling population

Background

To date, numerous studies have investigated the relationship between the triglyceride glucose (TyG) index and carotid plaques, but the impact of gender on this relationship has not been explored. Therefore, this study aims to investigate gender-specific differences in the relationship between the TyG index and carotid plaques in a high cardiovascular risk population in China.

Methods

This cross-sectional study's data were derived from a longitudinal pilot study involving 1,085 high-risk cardiovascular subjects. A multivariable logistic regression model was used to analyze the relationship between the TyG index and carotid plaques. A generalized additive model combined with a stratified regression model was employed to assess the nonlinear relationship between the TyG index and carotid plaques across different genders. In the nonlinear relation, the inflection point was calculated by a two-piecewise linear regression model.

Results

After adjusting for confounders such as age, sex, BMI, SBP, DBP, AST/ALT, TC, LDL-c, HDL-c, creatinine, smoking, and antilipemic medication, the generalized additive model results revealed a nonlinear relationship between the TyG index and carotid plaque formation, with significant differences across genders. In males, the relationship between the TyG index and carotid plaques was S-shaped. The two-piecewise linear regression model identified two inflection points: TyG = 8.39 (P = 0.017) and TyG = 10.2 (P = 0.009).

Conclusion

The relationship between the TyG index and the formation of carotid plaques is nonlinear, and there are significant differences in the correlation between males and females.

Oppression-Based Stress and Alcohol Inequities Among Sexual and Gender Minority People: An Intersectional Multilevel Framework

PURPOSE

Sexual and gender minority (SGM) people are at heightened risk for alcohol use, hazardous drinking, and alcohol use disorder compared to heterosexual and cisgender individuals. This paper: (a) presents an oppression framework that integrates intersectionality, stress, stigma, and addiction-based theories to examine the complex and nuanced ways oppression-based stress (e.g., minority stress) leads to sexual orientation and gender identity inequities in alcohol use; (b) conducts a narrative review that summarizes recent and novel advancements in the literature on the impact of oppression-based stressors on alcohol use outcomes across structural, interpersonal, and intrapersonal domains among SGM people; and (c) provides future research and intervention directions for the alcohol field.

SEARCH METHODS

A select review of the literature was conducted on July 10, 2023, using multiple electronic databases (i.e., PsycInfo, PubMed, Web of Science) and focusing on studies that had examined the associations between oppression-based stressors and alcohol use outcomes across structural, interpersonal, and intrapersonal levels. Search terms focused on alcohol consumption; SGM people, particularly SGM people of color; and oppression-based stress. Cross-sectional studies that focused on heterosexism-based and anti-bisexual oppression-based stressors at the interpersonal or intrapersonal levels and alcohol use outcomes were excluded as they have been included in prior reviews of the literature.

SEARCH RESULTS

The initial and combined search across the databases resulted in 3,205 articles. Of those, the narrative review included 50 peer-reviewed articles that focused on the following four areas of the literature on the associations between oppression-based stressors and alcohol use outcomes: (1) experimental, longitudinal, and experience sampling studies of heterosexism- and anti-bisexual oppression-based stressors (22 articles); (2) any studies of cissexism-based stressors (12 articles); (3) any studies of intersectional oppression among SGM people of color (seven articles, one article overlapped with the first category and another overlapped with the fourth category); and (4) any studies of structural oppression (11 articles).

DISCUSSION AND CONCLUSIONS

Results of this narrative review indicate that mounting evidence implicates oppression-based stress in inequities in alcohol use, hazardous drinking, and alcohol use disorder in SGM populations. This reflects SGM people's embodiment of oppression and injustice at the structural, interpersonal, and intrapersonal levels. Given some inconsistent and mixed patterns of findings, future research needs greater specificity in drinking inclusion criteria, robust and well-validated measures, more attention to culturally and developmentally relevant moderating and mediating mechanisms across the lifespan, application of sophisticated methodologies, and integration of intersectional and addiction frameworks.

Stress and substance use disorders: risk, relapse, and treatment outcomes

Stress has long been associated with substance misuse and substance use disorders (SUDs). The past two decades have seen a surge in research aimed at understanding the underlying mechanisms driving this association. This Review introduces a multilevel "adaptive stress response" framework, encompassing a stress baseline, acute reaction, and recovery with return-to-homeostasis phase that occurs at varying response times and across domains of analysis. It also discusses evidence showing the disruption of this adaptive stress response in the context of chronic and repeated stressors, trauma, adverse social and drug-related environments, as well as with acute and chronic drug misuse and with drug withdrawal and abstinence sequelae. Subjective, cognitive, peripheral, and neurobiological disruptions in the adaptive stress response phases and their link to inflexible, maladaptive coping; increased craving; relapse risk; and maintenance of drug intake are also presented. Finally, the prevention and treatment implications of targeting this "stress pathophysiology of addiction" are discussed, along with specific aspects that may be targeted in intervention development to rescue stress-related alterations in drug motivation and to improve SUD treatment outcomes.

The Role of Perceived Stress in the Relation between Childhood Maltreatment and Severity of Alcohol Use Disorder: A Mediation Analysis

INTRODUCTION

Experiences of Childhood Maltreatment (CM) relate to relapse and lower treatment success in Alcohol Use Disorder (AUD), one of the most prevalent substance use disorders. However, the exact mechanisms of this relationship still remain unclear. This study examines perceived stress and "drinking to cope with negative affect" (coping) as possible mediators in this relationship. Moreover, it aims at uncovering the differential effects of the subtypes of CM.

METHODS

N = 96 individuals (42% women; mean age 41 ± 13 years) including healthy controls and individuals with varying severity of AUD and CM completed the Alcohol-Dependence Scale, Childhood Trauma Questionnaire, Perceived Stress Scale and German Inventory of Drinking Situations. Mediation analyses including perceived stress as a mediator between CM (and subtypes) and severity of AUD, as well as a serial mediation of the relationship between CM and AUD severity by perceived stress and coping were conducted.

RESULTS

Perceived stress significantly mediated the relation between CM and AUD severity and the serial mediation by perceived stress and coping turned out significant. Subtype-specific analyses did not yield significant results.

CONCLUSION

This study reinforces perceived stress as a potential mechanism in the relation between CM and AUD severity. Moreover, coping further mediated the relationship between CM and AUD severity. Our results suggest including screening for CM (subtypes) in clinical routine in order to individually emphasize interventions focusing on stress regulation, as well as on developing healthy coping mechanisms, in patients with AUD. This might prevent heightened stress sensitivity, relapse and further maintenance of AUD.

INTRODUCTION

Experiences of Childhood Maltreatment (CM) relate to relapse and lower treatment success in Alcohol Use Disorder (AUD), one of the most prevalent substance use disorders. However, the exact mechanisms of this relationship still remain unclear. This study examines perceived stress and "drinking to cope with negative affect" (coping) as possible mediators in this relationship. Moreover, it aims at uncovering the differential effects of the subtypes of CM.

METHODS

N = 96 individuals (42% women; mean age 41 ± 13 years) including healthy controls and individuals with varying severity of AUD and CM completed the Alcohol-Dependence Scale, Childhood Trauma Questionnaire, Perceived Stress Scale and German Inventory of Drinking Situations. Mediation analyses including perceived stress as a mediator between CM (and subtypes) and severity of AUD, as well as a serial mediation of the relationship between CM and AUD severity by perceived stress and coping were conducted.

RESULTS

Perceived stress significantly mediated the relation between CM and AUD severity and the serial mediation by perceived stress and coping turned out significant. Subtype-specific analyses did not yield significant results.

CONCLUSION

This study reinforces perceived stress as a potential mechanism in the relation between CM and AUD severity. Moreover, coping further mediated the relationship between CM and AUD severity. Our results suggest including screening for CM (subtypes) in clinical routine in order to individually emphasize interventions focusing on stress regulation, as well as on developing healthy coping mechanisms, in patients with AUD. This might prevent heightened stress sensitivity, relapse and further maintenance of AUD.

The role of resilience in the relationship between stress and alcohol

Stress plays a well-documented role in alcohol consumption and the risk for developing alcohol use disorder. The concept of resilience - coping with and successfully adapting to stressful life experiences - has received increasing attention in the field of addiction research in recent decades, and there has been an accumulation of evidence for resilience as a protective factor against problematic alcohol consumption, risk for alcohol use disorder, disorder severity, and relapse. The conceptual and methodological approaches used in the generation of this evidence vary considerably across investigations, however. In light of this, we carried out this review in order to provide a more thorough understanding of the meaning and scope of resilience, what factors contribute to resilience, how it is measured, and how it relates to alcohol-associated phenotypes. Implications for treatment through the use of resilience-building interventions are likewise discussed, as well as implications for future research on the role of resilience in the etiology and clinical outcomes of alcohol use disorder.

Chronic alcohol consumption alters sex-dependent BNST neuron function in rhesus macaques

Repeated alcohol drinking contributes to a number of neuropsychiatric diseases, including alcohol use disorder and co-expressed anxiety and mood disorders. Women are more susceptible to the development and expression of these diseases with the same history of alcohol exposure as men, suggesting they may be more sensitive to alcohol-induced plasticity in limbic brain regions controlling alcohol drinking, stress responsivity, and reward processing, among other behaviors. Using a translational model of alcohol drinking in rhesus monkeys, we examined sex differences in the basal function and plasticity of neurons in the bed nucleus of the stria terminalis (BNST), a brain region in the extended amygdala shown to be a hub circuit node dysregulated in individuals with anxiety and alcohol use disorder. We performed slice electrophysiology recordings from BNST neurons in male and female monkeys following daily "open access" (22 h/day) to 4% ethanol and water for more than one year or control conditions. We found that BNST neurons from control females had reduced overall current density, hyperpolarization-activated depolarizing current (Ih), and inward rectification, as well as higher membrane resistance and greater synaptic glutamatergic release and excitatory drive, than those from control males, suggesting that female BNST neurons are more basally excited than those from males. Chronic alcohol drinking produced a shift in these measures in both sexes, decreasing current density, Ih, and inward rectification and increasing synaptic excitation. In addition, network activity-dependent synaptic inhibition was basally higher in BNST neurons of males than females, and alcohol exposure increased this in both sexes, a putative homeostatic mechanism to counter hyperexcitability. Altogether, these results suggest that the rhesus BNST is more basally excited in females than males and chronic alcohol drinking produces an overall increase in excitability and synaptic excitation. These results shed light on the mechanisms contributing to the female-biased susceptibility to neuropsychiatric diseases including co-expressed anxiety and alcohol use disorder.

Chronic alcohol consumption alters sex-dependent BNST neuron function in rhesus macaques

Repeated alcohol drinking contributes to a number of neuropsychiatric diseases, including alcohol use disorder and co-expressed anxiety and mood disorders. Women are more susceptible to the development and expression of these diseases with the same history of alcohol exposure as men, suggesting they may be more sensitive to alcohol-induced plasticity in limbic brain regions controlling alcohol drinking, stress responsivity, and reward processing, among other behaviors. Using a translational model of alcohol drinking in rhesus monkeys, we examined sex differences in the basal function and plasticity of neurons in the bed nucleus of the stria terminalis (BNST), a brain region in the extended amygdala shown to be a hub circuit node dysregulated in individuals with anxiety and alcohol use disorder. We performed slice electrophysiology recordings from BNST neurons in male and female monkeys following daily "open access" (22 hr/day) to 4% ethanol and water for more than one year or control conditions. We found that BNST neurons from control females had reduced overall current density, hyperpolarization-activated depolarizing current (Ih), and inward rectification, as well as higher membrane resistance and greater synaptic glutamatergic release and excitatory drive, than those from control males, suggesting that female BNST neurons are more basally excited than those from males. Chronic alcohol drinking produced a shift in these measures in both sexes, decreasing current density, Ih, and inward rectification and increasing synaptic excitation. In addition, network activity-dependent synaptic inhibition was basally higher in BNST neurons of males than females, and alcohol exposure increased this in both sexes, a putative homeostatic mechanism to counter hyperexcitability. Altogether, these results suggest that the rhesus BNST is more basally excited in females than males and chronic alcohol drinking produces an overall increase in excitability and synaptic excitation. These results shed light on the mechanisms contributing to the female-biased susceptibility to neuropsychiatric diseases including co-expressed anxiety and alcohol use disorder.

β-Endorphin influences sedative and ataxic effects of alcohol

Beta-endorphin (β-E) is an opioid peptide linked to the behavioral effects of ethanol. For example, β-E provides negative feedback to inhibit the hypothalamic-pituitary-adrenal (HPA) stress axis, and neuroadaptation of this system to ethanol may facilitate sex differences in disordered drinking. Locomotor sensitivity to ethanol may also influence the risk for addiction; however, the role of β-E in psychomotor effects of ethanol is not fully understood. We examined the role of β-E and sex on locomotor effects of ethanol using adult male and female wild-type C57BL/6J and β-E deficient B6.129S2-Pomctm1Low/J mice in a parallel rod floor apparatus following 0.75 or 2.0 g/kg ethanol. Beginning 15 min after intraperitoneal injection, we recorded foot slips, distance traveled, slips per meter, first instance of immobility, and total time spent off-balance (lying on the floor) over 15 min, and collected blood for analysis of ethanol concentration 60 min after injection. Overall, β-E deficient mice were more sedated and ataxic following ethanol; at the lower dose they slipped more frequently and had a higher rate of slips per meter traveled. At the higher dose, β-E deficient mice were predominantly sedated, slipping less frequently, and traveling less, as well as spending more time off-balance and becoming immobile sooner. Genotype interacted with sex in that male β-E deficient mice slipped more frequently than their female counterparts, suggesting that β-E may elicit sex-dependent effects of ethanol-induced ataxia. Blood ethanol concentration did not differ between any group, suggesting that behavioral differences result from altered sensitivity to ethanol. Our data support the contention that β-E modulates the locomotor effects of ethanol and may influence ataxia in a sex-dependent manner. These findings help elucidate the role of β-E in diverging behavioral responses to ethanol and may aid the development of targeted treatments for alcohol use disorders.

Stress-Induced Sensitization of Insula Activation Predicts Alcohol Craving and Alcohol Use in Alcohol Use Disorder

BACKGROUND

Stress and alcohol cues trigger alcohol consumption and relapse in alcohol use disorder. However, the neurobiological processes underlying their interaction are not well understood. Thus, we conducted a randomized, controlled neuroimaging study to investigate the effects of psychosocial stress on neural cue reactivity and addictive behaviors.

METHODS

Neural alcohol cue reactivity was assessed in 91 individuals with alcohol use disorder using a validated functional magnetic resonance imaging (fMRI) task. Activation patterns were measured twice, at baseline and during a second fMRI session, prior to which participants were assigned to psychosocial stress (experimental condition) or a matched control condition or physical exercise (control conditions). Together with fMRI data, alcohol craving and cortisol levels were assessed, and alcohol use data were collected during a 12-month follow-up. Analyses tested the effects of psychosocial stress on neural cue reactivity and associations with cortisol levels, craving, and alcohol use.

RESULTS

Compared with both control conditions, psychosocial stress elicited higher alcohol cue-induced activation in the left anterior insula (familywise error-corrected p < .05) and a stress- and cue-specific dynamic increase in insula activation over time (F22,968 = 2.143, p = .007), which was predicted by higher cortisol levels during the experimental intervention (r = 0.310, false discovery rate-corrected p = .016). Cue-induced insula activation was positively correlated with alcohol craving during fMRI (r = 0.262, false discovery rate-corrected p = .032) and alcohol use during follow-up (r = 0.218, false discovery rate-corrected p = .046).

CONCLUSIONS

Results indicate a stress-induced sensitization of cue-induced activation in the left insula as a neurobiological correlate of the effects of psychosocial stress on alcohol craving and alcohol use in alcohol use disorder, which likely reflects changes in salience attribution and goal-directed behavior.