Self-report of alcohol use for pain in a multi-ethnic community sample

Tribal Identity, Pain Interference, and Substance Use Among American Indian and Alaska Native Adolescents

Importance

Substance use is high among American Indian/Alaska Native adolescents. Pain interference is a risk factor for substance use, and identifying potential protective factors, such as Tribal identity, is important to help inform culturally grounded substance use prevention strategies.

Objective

To examine the protective potential of Tribal identity as a moderator in the association between pain interference and substance use in American Indian/Alaska Native adolescents.

Design, Setting, and Participants

This cross-sectional study of 10th-grade students self-identifying as American Indian/Alaska Native was conducted among students enrolled at 20 high schools on or near the Cherokee Nation Reservation. Data for this study were collected from the baseline assessments of a cluster randomized trial to prevent substance use among adolescents living on or near the Cherokee Nation Reservation. Inclusion criteria for high schools' participation included being located within counties that partially or fully fall within the Cherokee Nation reservation, a town population of 3000 individuals or fewer, and class sizes between 30 and 100 students. Exclusion criteria included high schools within metropolitan and micropolitan cores (per the US Census Bureau's Rural-Urban Commuting Area codes) and the existence of an established community drug prevention coalition. Student surveys were conducted from September 2021 to May 2024.

Exposure

Pain interference in the 7 days prior to baseline assessment.

Main Outcomes and Measures

The primary outcomes were past 30-day alcohol use, marijuana use, and prescription opioid misuse. Generalized estimating equations Poisson models were used, with an exchangeable correlation structure clustered on the school level using baseline data from a cluster randomized trial to prevent alcohol and substance use among adolescents. For each substance, a separate multivariable model was fit, which included pain interference, Tribal identity, an interaction term between pain interference and Tribal identity, age, gender, food insecurity, anxiety symptoms, and depressive symptoms.

Results

Among 514 self-identified American Indian/Alaska Native students at 20 high schools on or near the Cherokee Nation Reservation, mean (SD) participant age was 15.59 (0.62) years, and 252 participants (49.0%) self-identified as female. Pain interference was associated with alcohol use and prescription opioid misuse in American Indian/Alaska Native adolescents, controlling for age, gender, food insecurity, anxiety symptoms, and depressive symptoms. Tribal identity significantly moderated the association between pain interference and alcohol use (coefficient, -0.13; 95% CI, -0.23 to -0.02).

Conclusions and Relevance

When Tribal identity was high, the adverse association of pain interference with alcohol use was significantly attenuated. This demonstrates a protective role of Tribal identity on alcohol use, which can inform future substance use prevention efforts among American Indian/Alaska Native adolescents.

Trial Registration

ClinicalTrials.gov Identifier: NCT04839978.

Alcohol use disorder in the perioperative period: a summary and recommendations for anesthesiologists and pain physicians

Excessive alcohol consumption and alcohol use disorder (AUD) increase the risk of perioperative morbidity and mortality. Aspiration, malnutrition, coagulopathies, seizures, and hemodynamic alterations are only a few of the major concerns related to acute alcohol intoxication and AUD. There are also numerous physiological effects, changes in medication metabolism and pharmacology, and adverse events related to chronic alcohol consumption. These are all important considerations for the anesthesiologist in the perioperative management of a patient with AUD. Pain perception and thresholds are altered in patients with acute and chronic alcohol use. Medications used to manage AUD symptoms, particularly naltrexone, can have significant perioperative implications. Patients on naltrexone who continue or stop this medication in the perioperative period are at an increased risk for undertreated pain or substance use relapse. This review highlights key considerations for the anesthesiologist and pain physician in the perioperative management of patients with active AUD (or those in recovery). It discusses the effects of acute and chronic alcohol use on pain perception and thresholds, provides guidance on the perioperative management of naltrexone and low-dose naltrexone, and reviews a multimodal approach to pain management.

Determinants of perceived pain relief from acute alcohol intake in a laboratory setting

Background

Studies of alcohol analgesia often assume that changes in pain sensitivity reflect the negative reinforcing effects of alcohol in pain self-management. However, factors that may influence perceived pain relief due to alcohol use remain incompletely characterized. Thus, the primary aim of this study was to identify which factors are most strongly related to self-reported pain relief in individuals with and without chronic pain after alcohol consumption.

Methods

This study combined data from two studies of alcohol analgesia in individuals who regularly consume alcohol with and without chronic pain. Alcohol analgesia expectancies were assessed during screening. In laboratory sessions, participants received an alcohol-containing (.08 g/dL target BrAC) or placebo beverage and rated subjective intoxication and subjective response (positive/negative aspects of stimulation/sedation). Participants underwent quantitative sensory testing to measure pain intensity, pain threshold, and relief. Paired sample t-tests determined effects of alcohol on pain measures. Hierarchical linear models determined factors associated with pain relief ratings in the alcohol condition.

Results

Pain relief and pain threshold were higher in the alcohol session relative to placebo, but pain intensity did not differ. In a 4-step hierarchical linear model, expectancy of pain relief, subjective intoxication, and high positive affect, but not pain threshold or pain intensity, were significantly and uniquely associated with perceived relief.

Conclusions

Taken together, results suggest the negative-reinforcing effects of alcohol for pain-management are not completely reflected by changes in pain sensitivity in a laboratory setting. Expectancies and subjective response may be important in determining an individual's evaluation of alcohol's efficacy for pain self-management.

High-risk use of prescription opioids among patients treated for alcohol problems in New York State. A repeated cross-sectional study, 2005-2018

Background

Patients with alcohol use disorder (AUD) and high-risk opioid use are at risk of serious complications. The purpose of this study was to estimate the prevalence of and factors associated with high-risk opioid use in patients with an alcohol use problem from 2005 to 2018.

Methods

This repeated cross-sectional study analyzed data from first admissions for alcohol treatment (2005-2018) to the NYS Office of Addiction Services and Supports merged with Medicaid Claims Data. High-risk opioid use was defined as opioid dose ≥50 morphine mg equivalents (MME) per day; opioid prescriptions overlapping ≥7 days; opioids for chronic pain >90 days or opioids for acute pain >7 days.

Results

Patients receiving ≥50 MME increased from 690 to 3226 from 2005 to 2010; then decreased to 2330 in 2018. From 2005-2011, patients with opioid prescriptions overlapping ≥7 days increased from 226 to 1594 then decreased to 892 in 2018. From 2005-2010, opioid use >7 days for acute pain increased from 133 to 970 and plateaued after 2010. From 2005-2018, patients who received opioids >90 days for chronic pain trended from 186 to 1655. White patients, females, age 36-55, patients with chronic and acute pain diagnoses had the highest rates of high-risk use.

Conclusions

The prevalence of high-risk opioid use in patients with alcohol use problems increased from 2005 to 2011, and generally decreased after 2010. However, prevalence of opioids >90 days for chronic pain trended up from 2005 to 2018. High-risk opioid use among patients with AUD emphasizes the need to develop interventional strategies to improve patient care.

Neural correlates of proactive avoidance deficits and alcohol use motives in problem drinking

Physical pain and negative emotions represent two distinct drinking motives that contribute to harmful alcohol use. Proactive avoidance, in contrast, can reduce consumption in response to these motives but appears to be impaired in those with problem drinking. Despite such evidence, proactive avoidance and its underlying neural deficits have not been assessed experimentally. How these deficits inter-relate with drinking motives to influence alcohol use also remains unclear. The current study leveraged neuroimaging data in forty-one problem and forty-one social drinkers who performed a probabilistic learning go/nogo task featuring proactive avoidance of painful outcomes. We identified the brain responses to proactive avoidance and contrasted the neural correlates of drinking to avoid negative emotions vs. physical pain. Behavioral results confirmed proactive avoidance deficits in problem drinking individuals' learning rate and performance accuracy, both which were associated with greater alcohol use. Imaging findings in the problem drinking group showed that negative emotions as a drinking motive predicted attenuated right anterior insula activation during proactive avoidance. In contrast, physical pain motive predicted reduced right putamen response. These regions' activations as well as functional connectivity with the somatomotor cortex also demonstrated a negative relationship with drinking severity and positive relationship with proactive avoidance performance. Path modeling further delineated the pathways through which physical pain and negative emotions influenced the neural and behavioral measures of proactive avoidance. Taken together, the current findings provide experimental evidence for proactive avoidance deficits in alcohol misuse and establish the link between their neural underpinnings and drinking behavior.

Adolescent alcohol exposure promotes mechanical allodynia and alters synaptic function at inputs from the basolateral amygdala to the prelimbic cortex

Binge drinking is common among adolescents despite mounting evidence linking it to various adverse health outcomes that include heightened pain perception. The prelimbic (PrL) cortex is vulnerable to insult from adolescent alcohol exposure and receives input from the basolateral amygdala (BLA) while sending projections to the ventrolateral periaqueductal gray (vlPAG) - two brain regions implicated in nociception. In this study, adolescent intermittent ethanol (AIE) exposure was carried out in male and female rats using a vapor inhalation procedure. Assessments of mechanical and thermal sensitivity revealed that AIE exposure induced protracted mechanical allodynia. To investigate synaptic function at BLA inputs onto defined populations of PrL neurons, retrobeads and viral labelling were combined with optogenetics and slice electrophysiology. Recordings from retrobead labelled cells in the PrL revealed AIE reduced BLA driven feedforward inhibition of neurons projecting from the PrL to the vlPAG, resulting in augmented excitation/inhibition (E/I) balance and increased intrinsic excitability. Consistent with this finding, recordings from virally tagged PrL parvalbumin interneurons (PVINs) demonstrated that AIE exposure reduced both E/I balance at BLA inputs onto PVINs and PVIN intrinsic excitability. These findings provide compelling evidence that AIE alters synaptic function and intrinsic excitability within a prefrontal nociceptive circuit.

Pleiotropy and genetically inferred causality linking multisite chronic pain to substance use disorders

Individuals suffering from chronic pain develop substance use disorders (SUDs) more often than others. Understanding the shared genetic influences underlying the comorbidity between chronic pain and SUDs will lead to a greater understanding of their biology. Genome-wide association statistics were obtained from the UK Biobank for multisite chronic pain (MCP, Neffective = 387,649) and from the Million Veteran Program and the Psychiatric Genomics Consortium meta-analyses for alcohol use disorder (AUD, Neffective = 296,974), cannabis use disorder (CanUD, Neffective = 161,053), opioid use disorder (OUD, Neffective = 57,120), and problematic tobacco use (PTU, Neffective = 270,120). SNP-based heritability was estimated for each of the traits and genetic correlation (rg) analyses were performed to assess MCP-SUD pleiotropy. Bidirectional Mendelian Randomization analyses evaluated possible causal relationships. Finally, to identify and characterize individual loci, we performed a genome-wide pleiotropy analysis and a brain-wide analysis using imaging phenotypes available from the UK Biobank. MCP was positively genetically correlated with AUD (rg = 0.26, p = 7.55 × 10-18), CanUD (rg = 0.37, p = 8.21 × 10-37), OUD (rg = 0.20, p = 1.50 × 10-3), and PTU (rg = 0.29, p = 8.53 × 10-12). Although the MR analyses supported bi-directional relationships, MCP had larger effects on AUD (pain-exposure: beta = 0.18, p = 8.21 × 10-4; pain-outcome: beta = 0.07, p = 0.018), CanUD (pain-exposure: beta = 0.58, p = 2.70 × 10-6; pain-outcome: beta = 0.05, p = 0.014) and PTU (pain-exposure: beta = 0.43, p = 4.16 × 10-8; pain-outcome: beta = 0.09, p = 3.05 × 10-6) than the reverse. The genome-wide analysis identified two SNPs pleiotropic between MCP and all SUD investigated: IHO1 rs7652746 (ppleiotropy = 2.69 × 10-8), and CADM2 rs1248857 (ppleiotropy = 1.98 × 10-5). In the brain-wide analysis, rs7652746 was associated with multiple cerebellum and amygdala imaging phenotypes. When analyzing MCP pleiotropy with each SUD separately, we found 25, 22, and 4 pleiotropic variants for AUD, CanUD, and OUD, respectively. To our knowledge, this is the first large-scale study to provide evidence of potential causal relationships and shared genetic mechanisms underlying MCP-SUD comorbidity.

Identification of ethanol analgesia quantitative trait loci and candidate genes in BXD recombinant inbred mouse lines

Alcohol consumption produces acute analgesic effects, and people experiencing pain conditions may drink alcohol to alleviate discomfort. However, tolerance to the analgesic properties of alcohol could prompt escalating consumption and dependence. Both nociception and alcohol-induced analgesia are under significant genetic control. Understanding the genetic architecture of these processes could inform better treatment options for people with pain conditions. This study aims to identify quantitative trait loci (QTL) driving variation in ethanol-induced analgesia across BXD recombinant inbred mouse lines. Male and female mice from 62 BXD strains received ethanol or saline oral gavage for five days and were tested for hot plate (HP) latency at baseline, Day 1, and Day 5. QTL mapping of HP phenotypes identified a significant provisional QTL on chromosome 17 for Day 1 HP latency in mice receiving ethanol. An additional highly suggestive QTL was present on chromosome 9 for the difference in pre- and post-ethanol thermal nociception. Candidate genes within QTL support intervals were provisionally identified using HP phenotypic correlations to transcriptomic database, expression QTL analysis, and other bioinformatics inquiries. The combined behavioral and bioinformatic analyses yielded strong ethanol analgesia candidate genes, specifically Myo6. Thus, the results of this genetic study of ethanol-induced analgesia in BXD mouse strains may contribute significantly to our understanding of the molecular basis for individual variation in the analgesic response to acute ethanol.

Pain in alcohol use disorder: Evaluating effects of childhood trauma, perceived stress, and psychological comorbidity

The relationship between pain and alcohol use disorder (AUD) is complex and bidirectional. The current study examines risk factors for pain in a large comprehensively phenotyped sample including individuals from across the spectrum of alcohol use and misuse. Participants (n = 1101) were drawn from the National Institute on Alcohol Abuse and Alcoholism Natural History Protocol and included treatment-seeking AUD inpatients (AUD+Tx, n = 369), individuals with AUD not seeking treatment (AUD+, n = 161), and individuals without AUD (AUD-, n = 571). General linear models were utilized to test the effects of AUD status, history of childhood trauma exposure, perceived stress, and psychological comorbidity on daily percent time in pain, as well as change in daily percent time in pain across the inpatient stay in AUD+Tx individuals. Overall, 60.2% individuals reported any pain, with a significantly higher prevalence in the AUD+Tx group (82.1%) compared to the AUD+ (56.5%) and AUD- (47.1%) groups. Daily percent time in pain was also highest in the AUD+Tx group (30.2%) and was further increased in those with a history of childhood abuse and comorbid posttraumatic stress disorder (PTSD). Years of heavy drinking and craving were also associated with increased percent time in pain in the AUD+Tx group. Percent time in pain decreased following acute withdrawal in the AUD+Tx group but plateaued around 25% just prior to discharge. Individuals seeking inpatient treatment for AUD, especially those with a history of childhood trauma and/or comorbid PTSD, report greater percent time in pain compared to those not seeking treatment and those without AUD. The prolonged experience of pain in abstinent AUD inpatients after the resolution of acute withdrawal may signal the early stages of protracted withdrawal. Integrative treatments targeting pain and other symptoms of protracted withdrawal may be effective in improving overall function in people with severe AUD.

Surgical incision pain induced an increase in alcohol consumption in mice

INTRODUCTION

Large population-based studies have suggested a link between increased alcohol use and reduced pain. In addition, these studies suggest that higher levels of pain intensity are associated with an increase in alcohol consumption and rates of hazardous drinking which potentiates the risk of developing alcohol use disorders (AUD). The mechanisms and determinants of the alcohol-pain interaction can be studied in preclinical studies.

METHODS

The overall goal of this study is to use animal models to explore the impact of acute postoperative pain on alcohol intake. To achieve this, we characterized the timeline and levels of alcohol intake and preference in mice after laparotomy in the 2-bottle choice paradigm.

RESULTS

Our results show that laparotomy surgery increased alcohol intake and preference in male mice but not females in the 2-bottle choice and 3-bottle choice assays. In addition, ketoprofen administration blocked the increase in alcohol consumption in male mice after laparotomy. We also found that changes in alcohol initial sensitivity and acute functional tolerance, using loss of righting reflex (LORR) response, occur after surgery in mice.

CONCLUSION

Taken together, these findings suggests that sex, pain and alcohol sensitivity-related factors may modulate the relationship between alcohol consumption and pain.

A Brief Screening Tool for Risk of Self-Medication of Pain With Substance Use

OBJECTIVES

Substance use and pain are both growing public health concerns globally. Evidence suggests that individuals may use substances in order to self-medicate their pain. The Catastrophizing, Anxiety, Negative Urgency, and Expectancy model was developed to provide a theoretical foundation for the modifiable risk factors implicated in self-medication of pain with substance use. This study aimed to use the outcomes in the Catastrophizing, Anxiety, Negative Urgency, and Expectancy model to develop a brief clinical screening tool to identify individuals at risk for self-medication.

METHODS

Participants (N = 520; M age = 38.8) were adults who endorsed the past three-month use of at least one substance and completed an online questionnaire. Logistic regression and receiver operator characteristic analyses were used to reduce the initial 104-item questionnaire to the items needed to achieve a minimum accuracy score of 0.95 and 0.90.

RESULTS

A 14-item and a 7-item questionnaire were derived from the initial larger questionnaire. Both of these questionnaires were significantly correlated with the outcome variables and were significantly associated with health risk and percent of use because of pain. The R2 values between the 14- and 7-item versions were only significantly different for the percent of alcohol use because of pain.

CONCLUSIONS

The study provides two brief screening tools to screen for individuals at risk for self-medication of pain with substance use that can be easily implemented within clinical settings. Further, the screening tools provide insight into modifiable risk factors for self-medication and may also be valuable to monitor treatment response.

Converging Effects of Chronic Pain and Binge Alcohol Consumption on Anterior Insular Cortex Neurons Projecting to the Dorsolateral Striatum in Male Mice

Chronic pain and alcohol use disorder (AUD) are highly comorbid, and patients with chronic pain are more likely to meet the criteria for AUD. Evidence suggests that both conditions alter similar brain pathways, yet this relationship remains poorly understood. Prior work shows that the anterior insular cortex (AIC) is involved in both chronic pain and AUD. However, circuit-specific changes elicited by the combination of pain and alcohol use remain understudied. The goal of this work was to elucidate the converging effects of binge alcohol consumption and chronic pain on AIC neurons that send projections to the dorsolateral striatum (DLS). Here, we used the Drinking-in-the-Dark (DID) paradigm to model binge-like alcohol drinking in mice that underwent spared nerve injury (SNI), after which whole-cell patch-clamp electrophysiological recordings were performed in acute brain slices to measure intrinsic and synaptic properties of AIC→DLS neurons. In male, but not female, mice, we found that SNI mice with no prior alcohol exposure consumed less alcohol compared with sham mice. Electrophysiological analyses showed that AIC→DLS neurons from SNI-alcohol male mice displayed increased neuronal excitability and increased frequency of miniature excitatory postsynaptic currents. However, mice exposed to alcohol prior to SNI consumed similar amounts of alcohol compared with sham mice following SNI. Together, our data suggest that the interaction of chronic pain and alcohol drinking have a direct effect on both intrinsic excitability and synaptic transmission onto AIC→DLS neurons in mice, which may be critical in understanding how chronic pain alters motivated behaviors associated with alcohol.

Hazardous Alcohol Use Among Community-Dwelling Older Adults With Persistent or Recurrent Pain: Findings From the Health and Retirement Study

BACKGROUND

Although pain and alcohol use are highly prevalent and associated with deleterious health outcomes among older adults, a paucity of literature has examined hazardous drinking among older adults with pain. We aimed to examine the prevalence of hazardous drinking among a nationally representative sample of older adults with persistent or recurrent pain.

METHODS

We conducted cross-sectional analyses of data collected from the 2018 wave of the Health and Retirement Study. Participants included 1  549 community-dwelling adults aged ≥65 with persistent or recurrent pain (ie, clinically significant pain present at 2 consecutive survey waves).

RESULTS

More than one-quarter of older adults with persistent or recurrent pain reported regular alcohol use (≥weekly), nearly half of whom reported hazardous patterns of drinking. Specifically, 32% reported excessive drinking (ie, >2 drinks per day for older men; >1 drink per day for older women), and 22% reported binge drinking (ie, ≥4 drinks on one occasion). Exploratory analyses revealed a high prevalence of hazardous drinking among the subsample of older adults who used opioids (47%).

CONCLUSIONS

Hazardous alcohol use-including both excessive and binge drinking-is common among older adults with persistent or recurrent pain, including those who take opioids. Given that hazardous drinking can complicate pain management and increase the risk for adverse opioid effects (eg, overdose), the current findings underscore the importance of assessing and addressing hazardous patterns of alcohol use among older adults with persistent or recurrent pain.

Pain and Hazardous Alcohol Use in Veterans in Primary Care: The Role of Affective Pain Interference and Alcohol Pain-Coping Perceptions

Chronic pain and unhealthy alcohol use commonly co-occur and are associated with negative health outcomes. Veterans may be particularly vulnerable to these conditions, yet limited research has examined factors involved in their co-occurrence. This cross-sectional study aimed to examine the role of affective pain interference and alcohol pain-coping perceptions in the relationship between pain and hazardous alcohol use. As informed by the catastrophizing, anxiety, negative urgency, and expectancy model, we hypothesized that the relationship between pain and hazardous alcohol consumption is mediated by affective pain interference and stronger among those with greater perceptions that alcohol helps cope with pain. Participants were 254 VA primary care patients (87.8% male, Mage = 64.03, 76.4% White) with a history of chronic musculoskeletal pain, past-year alcohol use, and past-week pain. Veterans completed a mailed survey including measures of pain, affective pain interference, alcohol pain-coping perceptions, and hazardous alcohol use. Hypotheses were tested with regression models and PROCESS macros. As hypothesized, affective pain interference mediated the pain-hazardous alcohol use association. Contrary to hypotheses, results showed no moderating effect of alcohol pain-coping perceptions. Findings partially support relationships among theorized constructs and suggest that for Veterans with co-occurring pain and alcohol use it may be important to target pain-related affective interference and perceptions that alcohol helps cope with pain. PERSPECTIVE: This article presents a test of factors involved in the pain and alcohol relationship, as informed by the CANUE model. Findings suggest that for Veterans with co-occurring pain and past-year alcohol use, it may be important to target pain-related affective interference and perceptions that alcohol helps cope with pain.

Use and co-use of alcohol and cannabis following physical pain in the daily life of community adults engaged in regular substance use

OBJECTIVE

Alcohol and cannabis are often perceived as pain-relieving. However, minimal work has examined whether people use and co-use these substances following pain in daily life.

METHOD

Forty-six adults reporting weekly use of alcohol and/or cannabis completed a 60-day ecological momentary assessment protocol, answering at least four daily reports on their alcohol and cannabis use and pain (nassessments = 10,769 over 2,656 days). We examined whether self-reported pain so far that day (cumulative-average pain) was associated with subsequent alcohol and cannabis use and same-occasion co-use. Models also addressed whether associations differed for initiating versus continuing a use episode. Hypotheses were preregistered.

RESULTS

A multinomial multilevel model found that cumulative-average pain was associated with a greater likelihood of same-occasion co-use in the continuation phase but not the initiation phase, compared to no use (OR = 1.48,95% CI [1.06, 2.06], p = .023) and alcohol use (OR = 1.52, CI [1.03, 2.26], p = .037). Cumulative-average pain was largely not associated with alcohol-only and cannabis-only use. After alcohol use, greater pain was associated with cannabis use (OR = 1.37, CI [1.11, 1.70], p = .004), but not the reverse. Secondary analyses found greater previous-occasion (not cumulative) pain was associated with initiation of alcohol use and number of drinks, and initiation and continuation of cannabis use, but not number of cannabis hits.

CONCLUSIONS

Although not all hypotheses were supported, pain was associated with subsequent substance use in this sample engaged in regular substance use and not recruited for chronic pain. Cumulative pain may be particularly related to alcohol-cannabis same-occasion co-use, which may increase the risk of substance use-related problems over time. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Deficits in proactive avoidance and neural responses to drinking motives in problem drinkers

Physical pain and negative emotions represent two distinct drinking motives that contribute to harmful alcohol use. Proactive avoidance which can reduce problem drinking in response to these motives appears to be impaired in problem drinkers. However, proactive avoidance and its underlying neural deficits have not been assessed experimentally. How these deficits inter-relate with drinking motives to influence alcohol use also remains unclear. The current study leveraged neuroimaging data collected in forty-one problem and forty-one social drinkers who performed a probabilistic learning go/nogo task that involved proactive avoidance of painful outcomes. We characterized the regional brain responses to proactive avoidance and identified the neural correlates of drinking to avoid physical pain and negative emotions. Behavioral results confirmed problem drinkers' proactive avoidance deficits in learning rate and performance accuracy, both which were associated with greater alcohol use. Imaging findings in problem drinkers showed that negative emotions as a drinking motive predicted attenuated right insula activation during proactive avoidance. In contrast, physical pain motive predicted reduced right putamen response. These regions' activations as well as functional connectivity with the somatomotor cortex also demonstrated a negative relationship with drinking severity and positive relationship with proactive avoidance performance. Path modeling further delineated the pathways through which physical pain and negative emotions, along with alcohol use severity, influenced the neural and behavioral measures of proactive avoidance. Taken together, the current findings provide experimental evidence for proactive avoidance deficits in problem drinkers and establish the link between their neural underpinnings and alcohol misuse.

Alcohol use and the pain system

The World Health Organization's epidemiological data from 2016 revealed that while 57% of the global population aged 15 years or older had abstained from drinking alcohol in the previous year, more than half of the population in the Americas, Europe, and Western Pacific consumed alcohol. The spectrum of alcohol use behavior is broad: low-risk use (sensible and in moderation), at-risk use (e.g., binge drinking), harmful use (misuse) and dependence (alcoholism; addiction; alcohol use disorder). The at-risk use and misuse of alcohol is associated with the transition to dependence, as well as many damaging health outcomes and preventable causes of premature death. Recent conceptualizations of alcohol dependence posit that the subjective experience of pain may be a significant contributing factor in the transition across the spectrum of alcohol use behavior. This narrative review summarizes the effects of alcohol at all levels of the pain system. The pain system includes nociceptors as sensory indicators of potentially dangerous stimuli and tissue damage (nociception), spinal circuits mediating defensive reflexes, and most importantly, the supraspinal circuits mediating nocifensive behaviors and the perception of pain. Although the functional importance of pain is to protect from injury and further or future damage, chronic pain may emerge despite the recovery from, and absence of, biological damage (i.e., in the absence of nociception). Like other biological perceptual systems, pain is a construction contingent on sensory information and a history of individual experiences (i.e., learning and memory). Neuroadaptations and brain plasticity underlying learning and memory and other basic physiological functions can also result in pathological conditions such as chronic pain and addiction. Moreover, the negative affective/emotional aspect of pain perception provides embodied and motivational components that may play a substantial role in the transition from alcohol use to dependence.

Preoperative Factors Associated With Worse PROMIS Pain Interference 2 Years After Hand and Wrist Surgery

BACKGROUND

The purpose of this study was to identify preoperative factors associated with worse postoperative Patient-Reported Outcomes Measurement Information System (PROMIS) pain interference (PI) scores 2 years after hand and wrist surgery. We hypothesized that older age, more comorbidities, increased substance use, and lower socioeconomic status would correlate with worse 2-year PROMIS PI scores.

METHODS

This study was a retrospective review of prospectively acquired data on 253 patients. Surveys were administered within 1 week of surgery and 2 years postoperatively. Bivariate and multivariable analyses were conducted to identify significant predictors of worse 2-year PROMIS PI scores and change in PROMIS PI scores.

RESULTS

Older age, higher body mass index, more comorbidities, lower preoperative expectations, more prior surgeries, unemployment, smoking, higher American Society of Anesthesiologists (ASA) score, and multiple other socio-demographic factors were correlated with worse 2-year PROMIS PI scores (P ≤ .018). Similar factors were also correlated with less improvement in 2-year PROMIS PI scores (P ≤ .048). Worse scores on all preoperative patient-reported outcome measures correlated with worse 2-year PROMIS PI scores (P ≤ .007). Multivariable analysis identified smoking history, less frequent alcohol consumption, worse preoperative PROMIS social satisfaction and Numeric Pain Scale whole body scores, and higher ASA scores as independent predictors of worse 2-year PROMIS PI. The same factors in addition to better baseline PROMIS PI were predictive of less improvement in 2-year PROMIS PI.

CONCLUSION

Numerous preoperative factors were predictive of worse postoperative 2-year PROMIS PI and less improvement in 2-year PROMIS PI for patients undergoing hand and wrist surgery.

Clinical Phenomenology of Fibromyalgia Syndrome in Male Patients: Same But Different

The majority of knowledge about fibromyalgia syndrome (FMS) derives from studies of female patients. Little is known about the clinical characteristics and treatment outcomes of male patients with FMS. In this retrospective cohort study with a prospective posttreatment follow-up, we investigated whether male patients with FMS differ from female patients in terms of 1) symptom burden, 2) psychological characteristics, and 3) clinical treatment response. We identified 263 male (4%) out of 5,541 patients with FMS completing a 3-week multimodal pain-treatment program. Male patients (51.3 ± 9.1 years) were age- and time-matched (1:4) with female patients (N = 1,052, 51.3 ± 9.0 years). Data on clinical characteristics, psychological comorbidities, and treatment responses were obtained from medical records and validated questionnaires. Levels of perceived pain, psychological comorbidity, and functional capacity were similar between genders, although male patients with FMS showed a higher prevalence of alcohol abuse. Compared to female patients, male patients experienced themselves less often as overly accommodating (Cohen's d = -.42) but more often as self-sacrificing (d = .26) or intrusive (d = .23). Regarding pain coping, male patients were less likely to utilize mental distraction, rest- and relaxation techniques, or counteractive activities (d = .18-.27). Male patients showed a slightly worse overall response rate than women (69% vs 77%), although differences between individual outcome measures were small (d < .2). Although male and female patients in our cohort were similar in clinical presentation and treatment response, the gender-specific differences in interpersonal problems and pain coping suggest consideration of these aspects in the treatment of male patients with FMS. PERSPECTIVE: Knowledge about fibromyalgia mostly derives from studies of female patients. Identifying and understanding gender-specific differences in fibromyalgia is an important roadmap in the treatment of this syndrome by focusing on specific gender aspects such as differences in interpersonal problems and pain coping mechanisms.

Neural and Psychosocial Mechanisms Underlying Alcohol Use and Pain Interactions: Overview of Current Evidence and Future Directions

Purpose of Review

A growing body of research indicates bidirectional associations between alcohol use and pain. In this review, we highlight common neural and psychosocial mechanisms underlying pain and alcohol use and identify current gaps in the literature regarding alcohol/pain interactions. We also suggest future directions for the field moving forward, including more nuanced conceptualization of alcohol's negative reinforcing effects in the context of pain, broader use of clinically-relevant experimental pain induction modalities, and characterization of age, biological sex, gender, race, and ethnicity as moderators of pain/alcohol interactions.

Recent Findings

Acute alcohol intake has analgesic and negative-reinforcing effects in the context of pain, and chronic heavy alcohol use appears to increase risk for development of chronic pain. At the same time, pain, both acute and chronic, acts as a proximal antecedent for alcohol use and is associated with relapse risk for individuals in recovery from alcohol use disorder.

Summary

Although the links between alcohol use and pain are increasingly appreciated, significant gaps in understanding remain and systematic study of alcohol/pain interactions at all levels, including basic, preclinical, translational, and interventional, is needed.

Electroencephalography-Based Effects of Acute Alcohol Intake on the Pain Matrix

The effects of acute and chronic intakes of high doses of alcohol on pain perception are well known, ranging from short-term analgesic effects to long-term sensitization and polyneuropathies. The short-term analgesic effects of ethanol consumption on subjective pain perception have been well studied in the literature. Recent advances in neuroimaging allow for an insight into pain-related structures in the brain, fostering the mechanistic understanding of the processing of nociceptive input and pain. We aimed to utilize EEG, combined with standardized noxious mechanical/thermal stimulation and subjective pain testing, to research the effects of acute alcohol intake on nociceptive processing and pain perception. We recruited 12 healthy subjects in an unblinded cross-over study design and aimed at achieving a blood alcohol level of 0.1%. Our data revealed a significant reduction in subjective pain ratings to noxious thermal and mechanical stimuli after alcohol ingestion. Our EEG data revealed suppressing effects on the cortical structures responsible for processing pain, the "pain matrix". We conclude that in addition to its analgesic effects, as expressed by the reduction in subjective pain, alcohol has a further impact on the "pain matrix" and directly affects the salience to a nociceptive stimulus.

Does treating pain with alcohol affect drinking reduction among women with HIV enrolled in a clinical trial of naltrexone?

BACKGROUND

Many women living with HIV (WLWH) experience pain. Alcohol use with the intent to treat pain could lead to hazardous drinking and difficulty in reducing drinking. Naltrexone acts on opioid receptors important for pain regulation and is an approved treatment for alcohol use disorder. In this secondary analysis of a randomized double-blind placebo-controlled naltrexone clinical trial, the goals were to (1) compare alcohol reduction between women who drank to treat pain and those who did not and (2) examine differences in alcohol reduction by both drinking intention and treatment arm.

METHODS

Women living with HIV (N = 194, mean age 48.3 years, 83% non-Hispanic Black, 11% Hispanic) with hazardous drinking (>7 drinks/week) were randomized to receive daily treatment with naltrexone 50 mg or placebo for 4 months. Study visits occurred at baseline and 2, 4, and 7 months (posttreatment). The number of drinks/week was measured using the Timeline Follow Back. Use of alcohol to treat pain was self-reported. Participants were categorized as using alcohol to treat pain or not and in the naltrexone or placebo group. Chi-square, t-test, MANOVA, and sequential mixed effects models were used to determine group differences in demographic factors, mean/drinks per week, and percent change in mean drinks/week at baseline and each follow-up visit.

RESULTS

There was a consistent decrease in drinking throughout the study. There was not a significant difference in mean drinks/week at any point in the study between women who used alcohol to treat pain and those who did not. When considering treatment arm, at 2 months only those who did not use alcohol to treat pain in the naltrexone group had a significantly lower mean drinks/week than the other groups (p = 0.007); all groups had similar decreases in drinking from 4 months onward.

CONCLUSION

In the naltrexone group, WLWH who drank to treat pain reduced their alcohol consumption more slowly than WLWH who did not drink to treat pain. Replication of these findings would suggest that alcohol treatment guidelines should address pain as a factor in drinking outcomes.

Self-Reported Pain Treatment Practices Among U.S. and Canadian Adults: Findings From a Population Survey

Background and Objectives

Pain treatments and their efficacy have been studied extensively. Yet surprisingly little is known about the types of treatments, and combinations of treatments, that community-dwelling adults use to manage pain, as well as how treatment types are associated with individual characteristics and national-level context. To fill this gap, we evaluated self-reported pain treatment types among community-dwelling adults in the United States and Canada. We also assessed how treatment types correlate with individuals' pain levels, sociodemographic characteristics, and country of residence, and identified unique clusters of adults in terms of treatment combinations.

Research Design and Methods

We used the 2020 "Recovery and Resilience" United States-Canada general online survey with 2 041 U.S. and 2 072 Canadian community-dwelling adults. Respondents selected up to 10 pain treatment options including medication, physical therapy, exercise, etc., and an open-ended item was available for self-report of any additional treatments. Data were analyzed using descriptive, regression-based, and latent class analyses.

Results

Over-the-counter (OTC) medication was reported most frequently (by 55% of respondents, 95% CI 53%-56%), followed by "just living with pain" (41%, 95% CI 40%-43%) and exercise (40%, 95% CI 38%-41%). The modal response (29%) to the open-ended item was cannabis use. Pain was the most salient correlate, predicting a greater frequency of all pain treatments. Country differences were generally small; a notable exception was alcohol use, which was reported twice as often among U.S. versus Canadian adults. Individuals were grouped into 5 distinct clusters: 2 groups relied predominantly on medication (prescription or OTC), another favored exercise and other self-care approaches, one included adults "just living with" pain, and the cluster with the highest pain levels employed all modalities heavily.

Discussion and Implications

Our findings provide new insights into recent pain treatment strategies among North American adults and identify population subgroups with potentially unmet need for more adaptive and effective pain management.

Chronic alcohol induced mechanical allodynia by promoting neuroinflammation: A mouse model of alcohol-evoked neuropathic pain

BACKGROUND AND PURPOSE

Chronic pain is considered a key factor contributing to alcohol use disorder (AUD). The mechanisms responsible for chronic pain associated with chronic alcohol consumption are unknown. We evaluated the development of chronic pain in a mouse model of alcohol dependence and investigate the role of neuroinflammation.

EXPERIMENTAL APPROACH

The chronic-intermittent ethanol two-bottle choice CIE-2BC paradigm generates three groups: alcohol-dependent with escalating alcohol intake, nondependent (moderate drinking) and alcohol-naïve control male and female mice. We measured mechanical allodynia during withdrawal and after the last voluntary drinking. Immunoblotting was used to evaluate the protein levels of IBA-1, CSFR, IL-6, p38 and ERK2/1 in spinal cord tissue of dependent and non-dependent animals.

KEY RESULTS

We found significant escalation of drinking in the dependent group in male and female compared with the non-dependent group. The dependent group developed mechanical allodynia during 72 h of withdrawal, which was completely reversed after voluntary drinking. We observed an increased pain hypersensitivity compared with the naïve in 50% of non-dependent group. Increased IBA-1 and CSFR expression was observed in spinal cord tissue of both hypersensitivity-abstinence related and neuropathy-alcohol mice, and increased IL-6 expression and ERK1/2 activation in mice with hypersensitivity-related to abstinence, but not in mice with alcohol-evoked neuropathic pain.

CONCLUSIONS AND IMPLICATIONS

The CIE-2BC model induces two distinct pain conditions specific to the type of ethanol exposure: abstinence-related hypersensitivity in dependent mice and alcohol-evoked neuropathic pain in about a half of the non-dependent mice.

Identifying and addressing patient substance use: a survey of chiropractic clinicians

BACKGROUND

Chiropractors commonly encounter patients who present for spine pain with parallel substance use. There is currently no widespread training within the chiropractic profession to prepare chiropractors to recognize and address substance use in clinical practice. The purpose of this study was to examine chiropractors' confidence, self-perceptions, and interest in education associated with identifying and addressing patient substance use.

METHODS

A 10-item survey was developed by the authors. The survey addressed chiropractors' assessment of their training, experiences, and educational interest/needs regarding identifying and addressing patient substance use. The survey instrument was uploaded to Qualtrics and was electronically distributed to chiropractic clinicians at active and accredited English-speaking Doctor of Chiropractic degree programs (DCPs) in the United States.

RESULTS

A total of 175 individual survey responses were returned from a total of 276 eligible participants (63.4% response rate) from 16 out of 18 active and accredited English-speaking DCPs (88.8% of DCPs) in the United States. Nearly half of respondents strongly disagreed or disagreed (n = 77, 44.0%) that they were confident in their ability to identify patients who misuse prescription medication. The majority of respondents (n = 122, 69.7%) indicated that they did not have an established referral relationship with local clinical providers who provide treatment for individuals who use drugs or misuse alcohol or prescription medications. Most respondents strongly agreed or agreed (n = 157, 89.7%) that they would benefit from participating in a continuing education course on topics related to patients who use drugs or misuse alcohol or prescription medications.

CONCLUSIONS

Chiropractors indicated a need for training to help them identify and address patient substance use. There is a demand among chiropractors to develop clinical care pathways for chiropractic referrals and collaboration with health care professionals who provide treatment for individuals who use drugs or misuse alcohol or prescription medications.

Sex-specific biobehavioral regulation of persistent inflammatory pain by alcohol

BACKGROUND

Although a large percentage of chronic pain patients consume alcohol to manage their pain, there is a significant gap in knowledge regarding the mechanisms underlying the antinociceptive effects of alcohol.

METHODS

To determine the longitudinal analgesic effects of alcohol, we utilized the complete Freund's adjuvant (CFA) model of inflammatory pain in adult female and male Wistar rats. Both somatic and negative motivational aspects of pain were measured using the electronic von Frey (mechanical nociception) system, thermal probe test (thermal nociception), and mechanical conflict avoidance task (pain avoidance-like behavior). Tests were conducted at baseline and 1 and 3 weeks following intraplantar CFA or saline administration. At both time points post-CFA, animals were treated with each of three doses of alcohol (intraperitoneal; 0, 0.5, and 1.0 g/kg) over separate days in a Latin square design.

RESULTS

Alcohol produced dose-dependent mechanical analgesia and antihyperalgesia in females but only antihyperalgesia in males. Although alcohol continued to attenuate CFA-induced decreases in both thermal and mechanical nociceptive thresholds between 1 and 3 weeks post-CFA, it appeared less effective at increasing thresholds 3 weeks after CFA induction.

CONCLUSIONS

These data suggest that individuals may develop tolerance to alcohol's ability to alleviate both somatic and negative motivational symptoms of chronic pain over time. We also discovered sex-specific neuroadaptations in protein kinase A-dependent phosphorylation of GluR1 subunits and extracellular signal-regulated kinase (ERK 1/2) phosphorylation in nociceptive brain centers of animals receiving an alcohol challenge 1 week post-CFA. Together, these findings illustrate a sex-specific regulation of behavioral and neurobiological indices of persistent pain by alcohol.

Self-management with alcohol over lifespan: psychological mechanisms, neurobiological underpinnings, and risk assessment

Self-management includes all behavioural measures and cognitive activities aimed at coping with challenges arising throughout the lifespan. While virtually all of these challenges can be met without pharmacological means, alcohol consumption has long been instrumentalized as a supporting tool to help coping with problems arising selectively at adolescence, adulthood, and ageing. Here, we present, to our knowledge, the first systematic review of alcohol instrumentalization throughout lifespan. We searched MEDLINE, Google Scholar, PsycINFO and CINAHL (from Jan, 1990, to Dec, 2022) and analysed consumption patterns, goals and potential neurobiological mechanisms. Evidence shows a regular non-addictive use of alcohol to self-manage developmental issues during adolescence, adulthood, and ageing. Alcohol is selectively used to overcome problems arising from dysfunctional personality traits, which manifest in adolescence. A large range of psychiatric disorders gives rise to alcohol use for the self-management of distinct symptoms starting mainly in adulthood. We identify those neuropharmacological effects of alcohol that selectively serve self-management under specific conditions. Finally, we discuss the adverse effects and associated risks that arise from the use of alcohol for self-management. Even well-controlled alcohol use adversely impacts health. Based on these findings, we suggest the implementation of an entirely new view. Health policy action may actively embrace both sides of the phenomenon through a personalized informed use that allows for harm-controlled self-management with alcohol.

"I Was Literally Just Not Myself": How Chronic Pain Changes Multiple Frames of Identity

Though experienced by more than 1 in 5 (50 million) American adults, chronic pain is invisible, subjective, difficult to communicate, and often stigmatized. When faced with a serious injury or ongoing illness, individuals create an "illness identity" by modifying their goals and expectations for the future, adapting to impairments, and understanding new emotional reactions. The current, two-phase study uses the communication theory of identity (CTI) to explore the process of illness identity adoption in the context of chronic pain, which may be different than for more understood, less stigmatized illnesses. A focus group was conducted (N = 6), from which interview protocol were created. Interview participants (N = 23) described specific differences between their pre- and post-pain selves within three identity frames: personal, relational, and enacted. Within each frame, several sub-themes of pain-related identity changes are identified, as well how they were communicated and how they subsequently influenced communication. Additionally, three pain-related identity gaps, or ways in which two identity frames contradict each other, were identified, all created explicitly because of the onset of chronic pain: personal-enacted, personal-relational, and personal-communal. Theoretical contributions include using CTI to outline the illness identity adoption process in the context of chronic pain, identifying unique identity gaps created by this relatively widespread condition. Practically, understanding pain-related identity outcomes can help pain patients make sense of and manage their situation, and de-stigmatize the chronic pain experience.

Effects of ethanol on mechanical allodynia and dynamic weight bearing in male and female mice with spared nerve injury

BACKGROUND

Men and women with chronic pain report increased alcohol use and are more likely to be diagnosed with alcohol use disorder. The relationship between alcohol use and pain is bidirectional. Alcohol is used as an analgesic, but chronic alcohol intake increases pain. Sex differences in the relationship between chronic pain and alcohol are reported in the clinical and preclinical literature, but due to this bidirectional relationship, it is challenging to investigate the mechanisms that contribute to these differences. Thus, animal models of chronic pain are needed to characterize the efficacy of ethanol as an analgesic in males and females. The current experiments tested the hypothesis that ethanol differentially reduces pain behaviors in male and female mice in chronic neuropathic pain.

METHODS

The spared nerve injury (SNI) model was used to investigate the analgesic effects of multiple doses of ethanol (0.5, 1, 2, g/kg i.p.) in male and female mice using von Frey and dynamic weight-bearing (DWB) assays.

RESULTS

In both male and female mice, SNI led to robust allodynia and shifts in dynamic weight bearing. In male SNI mice, all three doses of ethanol fully reversed mechanical allodynia and shifts in DWB. In SNI females, only the highest dose (2.0 g/kg) was fully antiallodynic in the von Frey assay, while shifts in weight bearing were reversed at the 1.0 and 2.0 g/kg doses. The differences between male and females were not due to lower blood ethanol concentrations in female mice.

CONCLUSION

These data indicate that while ethanol has antiallodynic and antinociceptive effects in male and female mice, the doses and time course of these effects are distinct. Studies investigating the relationship between pain and ethanol exposure in mice should consider sex as a key variable. These data also inform reported sex differences in rodent models of chronic pain and in chronic pain patients.

Association of therapeutic and recreational reasons for alcohol use with alcohol demand

Motives for alcohol use and behavioral economic measures of demand are associated with alcohol consumption and alcohol-related problems. However, it is unclear how differences in reasons for alcohol use may affect alcohol demand. Additionally, although alcohol is commonly used to self-manage conditions such as pain and sleep problems, the impact of these reasons for alcohol use on alcohol demand is not well characterized. The present study addressed this gap. Participants were adults recruited via Amazon Mechanical Turk as part of a larger study investigating health behaviors. Analyses included participants who reported alcohol use in the past year (N = 637). Participants were categorized as having recreational, therapeutic, or both recreational and therapeutic reasons for using alcohol. A brief, three-item measure of alcohol demand was administered. Multivariate analysis of variance (MANOVA) analyses revealed that alcohol drinkers endorsing both recreational and therapeutic reasons for use had significantly higher average intensity, Omax, and breakpoint indices compared to those who only reported recreational or therapeutic drinking motives (ps < .05; Cohen's d = .09-.17). Secondary analyses revealed differences in demand according to therapeutic reason for alcohol use endorsed. Significant main effects were found for use to relieve pain and anxiety/depression/stress, while interactive effects were detected for use to relieve pain and improve sleep and use to relieve pain and anxiety/depression/stress. Overall, results suggest that alcohol demand is highest in drinkers who consume alcohol for both therapeutic and recreational reasons. This group may be at elevated risk for alcohol use disorder and alcohol-related consequences. Continued research is necessary to examine this possibility. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Thermal antinociceptive responses to alcohol in DBA/2J and C57BL/6J inbred male and female mouse strains

BACKGROUND

The phenomenon of alcohol analgesia and tolerance can facilitate misuse and lead to the development of alcohol use disorder (AUD). Numerous alcohol-induced behaviors are genetically influenced; however, it is unknown if alcohol analgesia has a genetic contribution. Rodent studies have shown that alcohol responses differ vastly between two widely studied inbred strains of mice, C57BL/6 J (B6) and DBA/2 J (D2). Here, we used B6 and D2 mice as an initial behavioral genetic analysis of acute alcohol-induced antinociception.

METHODS

The antinociceptive effect of orally-administered alcohol was characterized using the hot plate test in B6 and D2 mice of both sexes. Using the opioid receptor antagonist naloxone, the involvement of the opioid system was assessed. Locomotor activity and blood alcohol concentrations were also measured. Ovariectomized mice were used to evaluate the influence of ovarian sex hormones on alcohol-induced antinociception.

RESULTS

Alcohol induced an antinociceptive effect in B6 and D2 male mice in a time- and dose-dependent manner. In addition, D2 male mice were more sensitive to the antinociceptive effect of alcohol than B6 male mice. However, locomotion is not impeded by the tested doses of alcohol in B6 mice. Female D2 and B6 mice failed to show significant antinociceptive effects in alcohol dose-response studies. In addition, alcohol-induced antinociception was still not evident in ovariectomized female mice. Male mice of both strains developed tolerance to this effect after repeated administration of alcohol. Strain differences were found in blood alcohol concentration. Finally, no difference was found in the blockade of alcohol antinociception by 2 mg/kg naloxone.

CONCLUSION

Our results indicate that the antinociceptive effects of alcohol in the hot plate test are influenced by strain and sex. These findings support further genetic analysis of alcohol-induced antinociception to identify operative mechanisms and better assess the contribution of this phenotype to AUD.

Pain as a causal motivator of alcohol consumption: Associations with gender and race

Despite accumulating evidence indicating reciprocal interrelations between pain and alcohol consumption, no prior work has examined pain as a proximal antecedent of drinking. The goal of the current study was to test the effects of experimental pain induction on ad-lib alcohol consumption among moderate-to-heavy drinkers without chronic pain (N = 237; 42% female; 37% Black; M = 3.26daily drinks). Participants were randomized to either pain-induction (capsaicin + thermal heat paradigm) or no-pain-control conditions. Experimental pain induction lasted for 15 minutes, during which ad-lib alcohol consumption was assessed using an established taste test paradigm. As hypothesized, results indicated that participants randomized to the pain-induction condition poured and consumed more alcohol and reached a higher peak blood alcohol concentration than those randomized to the no-pain condition (ps < 0.05; ηp² range = 0.018-0.021). Exploratory analyses revealed the effects of pain on alcohol consumption to be most pronounced among participants who self-identified as male or Black (relative to female or White, respectively). These findings indicate that the experience of pain serves as a causal, situational motivator for alcohol consumption, and suggest that current drinkers may be susceptible to escalating their consumption of alcohol in the context of pain. Future research is needed to explicate observed differences in the effects of pain on drinking as a function of gender and race, and to extend this work to individuals with chronic pain and varying levels of alcohol use. Collectively, these findings may help inform the development of integrated treatments to address co-occurring pain and alcohol use. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Medication overuse headache and substance use disorder: A comparison based on basic research and neuroimaging

It has yet to be determined whether medication overuse headache (MOH) is an independent disorder or a combination of primary headache and substance addiction. To further explore the causes of MOH, we compared MOH with substance use disorder (SUD) in terms of the brain regions involved to draw more targeted conclusions. In this review, we selected alcohol use disorder (AUD) as a representative SUD and compared MOH and AUD from two aspects of neuroimaging and basic research. We found that in neuroimaging studies, there were many overlaps between AUD and MOH in the reward circuit, but the extensive cerebral cortex damage in AUD was more serious than that in MOH. This difference was considered to reflect the sensitivity of the cortex structure to alcohol damage. In future research, we will focus on the central amygdala (CeA), prefrontal cortex (PFC), orbital-frontal cortex (OFC), hippocampus, and other brain regions for interventions, which may have unexpected benefits for addiction and headache symptoms in MOH patients.

Differences in the Prevalence and Profile of DSM-IV and DSM-5 Alcohol Use Disorders-Results from the Singapore Mental Health Study 2016

INTRODUCTION

The Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) criteria for alcohol use disorders (AUD) was a significant shift from the historical DSM-IV Text Revised version. Following this shift in diagnostic criteria, a difference in the prevalence of AUD was expected. The current study aimed to evaluate the consequences of the modification of the diagnostic criteria from DSM-IV to DSM-5 AUD using lifetime diagnosis in Singapore's multi-ethnic population using data from a nationwide epidemiological study.

METHODS

Respondents were assessed for lifetime mental disorders using the Composite International Diagnostic Interview (CIDI) administered through face-to-face interviews. Lifetime DSM-IV AUD diagnoses were compared with DSM-5 AUD diagnoses generated by modifying the criteria and the addition of the craving criterion. Sociodemographic correlates of lifetime DSM-IV/DSM-5 AUD were examined using multiple logistic regression analysis. Associations between DSM-IV/DSM-5 AUD, chronic conditions, and the HRQOL summary scores were examined using logistic and linear regression after controlling for significant sociodemographic factors.

RESULTS

The lifetime prevalence of DSM-IV AUD was 4.6% (0.5% for dependence and 4.1% for abuse) in the adult population, while the lifetime prevalence of DSM-5 AUD was 2.2%. Younger age, male gender, and lower education were associated with higher odds of both DSM-IV and DSM-5 AUD. However, those who were economically inactive (versus employed) (AOR, 0.4; 95% CI 0.2-0.9) and had a higher monthly household income (SGD 4000-5999 versus below SGD 2000) had lower odds of DSM-IV AUD (AOR, 0.4; 95% CI 0.2-0.7), but this was not observed among those with DSM-5 AUD. Both DSM-IV and DSM-5 AUD were associated with significant comorbidities in terms of other mental disorders; however, those diagnosed with lifetime GAD had significantly higher odds of having DSM-5 AUD (AOR, 5; 95% CI 1.9-13.2) but not DSM-IV AUD.

CONCLUSIONS

While using the DSM-5 criteria would result in a lower prevalence of AUD in Singapore, it remains a highly comorbid condition associated with a poor health-related quality of life that is largely untreated, which makes it a significant public health concern.

Longitudinal associations between pain and substance use disorder treatment outcomes

INTRODUCTION

Pain is commonly reported among those in treatment for substance use disorders (SUD) and is associated with poorer SUD treatment outcomes. The current study examined the trajectory of pain over the course of SUD treatment and associations with substance use outcomes.

METHODS

This observational study included adults seeking treatment for alcohol, cannabis, or opioid use disorders (N = 811). Participants completed a battery of assessments at treatment admission, 30 days post admission, and at discharge, including measures of demographics, pain, quality of life, abstinence self-efficacy, and craving.

RESULTS

Analyses indicated linear reductions in pain intensity and interference over time. Significant interactive effects were observed for opioid use disorder (OUD) and time, such that participants with OUD had greater reductions in pain intensity and interference over time compared to those without OUD. Elevated pain intensity was associated with negative treatment outcomes, including reduced quality of life and abstinence self-efficacy, and greater craving and negative affect.

CONCLUSIONS

Reductions in pain occur over the course of SUD treatment, particularly for those with OUD. Greater pain was also associated with adverse SUD treatment outcomes. Results suggest that treatment and associated abstinence may be beneficial for those with co-occurring pain and SUD, highlighting an additional benefit of improving access to SUD treatment for patients and health care systems. Future research should replicate these findings among diverse samples and further characterize the trajectory of pain during and after SUD treatment.

Post-Combat-Injury Opioid Prescription and Alcohol Use Disorder in the Military

INTRODUCTION

Previous studies have identified combat exposure and combat traumatic experience as problematic drinking risk factors. Increasing evidence suggests that opioid use increases the risk of alcohol use disorder. This study investigated the association between opioid prescription use after injury and (1) alcohol use disorder and (2) severity of alcohol use disorder among deployed military servicemembers.

METHODS

Deidentified health records data of 9,029 deployed servicemembers from a retrospective cohort study were analyzed. Data were randomly selected from the Department of Defense Trauma Registry and included servicemembers with combat injuries during deployment in Iraq or Afghanistan (2002-2016). Pharmacy records and International Classification of Diseases, Ninth and Tenth Revision diagnosis codes were used. Three groups were identified (no opioid prescription use, nonpersistent opioid prescription use, and persistent opioid prescription use) and were compared on the basis of alcohol use disorder risk using Cox proportional hazard models. Data analyses were performed in 2021.

RESULTS

Of the 9,029 servicemembers with combat injury, 2,262 developed alcohol use disorder (1,322 developed severe alcohol use disorder). Compared with no opioid prescription use, increased alcohol use disorder risk was associated with persistent opioid prescription use, with a hazard ratio of 1.13 (95% CI=1.02, 1.26). After covariate adjustment, increased risk remained statistically significant (hazards ratio=1.24; 95% CI=1.10, 1.39). There was no significant difference in alcohol use disorder risk between no opioid prescription use and nonpersistent opioid prescription use. The risk of severe alcohol use disorder did not vary by opioid use among servicemembers with alcohol use disorder diagnosis.

CONCLUSIONS

The findings of the study suggest that the incidence of alcohol use disorder was higher among injured servicemembers with persistent opioid prescription use than among those without opioid use. If replicated in prospective studies, the findings highlight the need for clinicians to consider the current and history of alcohol use of patients in initiating treatment involving opioids.

Sex differences in associations between delay discounting and expectancies for alcohol analgesia

Self-medication of pain with alcohol is prevalent, and expectancies for alcohol analgesia likely influence pain relief and alcohol consumption. Hazardous alcohol use has been associated with greater delay discounting rates; however, little is known about the relationship between delay discounting and expectancies for alcohol analgesia. Therefore, the present study examined sex differences in associations between delay discounting and expectancies for alcohol analgesia. Healthy drinkers without chronic pain (N = 53) completed measures of expectancies for alcohol analgesia, alcohol use, and alcohol outcome expectancies. A five-trial adjusting-delay discounting task (DDT) for monetary outcomes was also administered. Regression analyses revealed that sex moderated the relationship between delay discounting and expectancies for alcohol analgesia. Steeper delay discounting rates were associated with weaker expectancies for alcohol analgesia among men when adjusting for average alcohol consumption. Among women, nonsignificant associations between delay discounting rates and expectancies for alcohol analgesia were observed. These findings provide initial evidence of sex differences in associations between delay discounting and expectancies for alcohol analgesia. The directionality of these associations was unexpected and may have implications for patterns of self-medication with alcohol. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Alcohol, Tobacco and Psychotropic Drugs Use Among a Population with Chronic Pain in Southern Spain. A Cross-Sectional Study

BACKGROUND

Substance use seems to be higher among populations with chronic pain.

AIM

The aim of this study is to examine the relationship between the quantity of alcohol, tobacco, and psychotropic drugs consumed and chronic pain among women and men.

METHOD

Linear and logistic regression analyses were carried out using data from the 2015-2016 adults' version of the Andalusian Health Survey which is a representative cross-sectional population-based study (n = 6,569 adults aged >16 years; 50.8% women; 49.2% men).

RESULTS

Disabling chronic pain was statistically associated with higher tobacco consumption among men (β = -30.0, 95% confidenct interval [CI] -59.5 to -0.60; t = -2.0; p < .05). Regarding alcohol, non-disabling chronic pain and a higher quantity of alcohol consumed are statistically associated for both sexes (women: β = 30.4, 95% CI 2.3-58.6; t = 2.12; p < .05 vs. men: β = 164.2, 95% CI 24.3-340.1); t = 2.30; p < .05). For women and men, both disabling chronic pain (women: odds ratio [OR] = 8.7, 95% CI 6.0-12.7); p < .05 vs. men: OR = 3.5, 95% CI 1.5-8.2); p < .05) and non-disabling chronic pain (women: OR = 3.7, 95% CI 2.0-7.0); p <.05 vs. men: OR = 4.7, 95% CI 95% CI 1.5-14.9); p < .05) were statistically significantly associated with a higher consumption of psychotropic drugs.

CONCLUSIONS

Chronic pain may be related to the quantity of alcohol, tobacco, and psychotropic drugs consumed, and disability appears to be one of the factors that modulates this relationship.

Analgesic effects of alcohol in adults with chronic jaw pain

BACKGROUND

Although recent literature provides promising support for the analgesic properties of alcohol, potential differences in alcohol analgesia as a function of chronic pain status are not well understood. Thus, this study examined chronic pain status as a potential moderator of alcohol analgesia and distinguished between multiple aspects of pain experience and sensitivity: pain threshold, pain intensity, pain unpleasantness, and perceived relief.

METHODS

Social drinkers with (N = 19) and without (N = 29) chronic jaw pain completed two testing sessions in a counterbalanced order: alcohol (target BrAC = 0.08 g/dl) and placebo. In each, pressure algometry was performed at the insertion of the masseter. Alcohol analgesia was assessed by examining the main and interactive effects of beverage condition, pressure level (4, 5, or 6 pound-feet [lbf]), and chronic jaw pain status (chronic pain vs. pain-free control) on quantitative sensory testing measures and pain relief ratings following noxious stimuli.

RESULTS

Analyses indicated significant increases in pain threshold and pain relief and reductions in pain unpleasantness and pain intensity, under the alcohol condition. Chronic pain participants demonstrated lower pain thresholds and greater pain intensity and pain unpleasantness ratings than controls. There were no interactive effects of alcohol and pain conditions on any pain measure.

CONCLUSIONS

Findings provide experimental evidence of alcohol's analgesic and pain-relieving effects and suggest that these effects do not significantly differ by chronic pain status. Individuals, who self-medicate pain via alcohol consumption, irrespective of pain status, may be at increased risk to engage in hazardous drinking patterns and thus experience adverse alcohol-related consequences.

Opioid and Alcohol Misuse in Veterans with Chronic Pain: A Risk Screening Study

In United States military veterans, chronic pain represents a risk factor for opioid and alcohol misuse, yet few studies have examined interactions among chronic pain, opioid prescription, and opioid and alcohol misuse. Previous work found substantial risk of co-morbid alcohol and opioid misuse in a community sample of opioid-prescribed individuals with chronic pain, a finding expanded upon here. Specifically, 211 veterans assessed within a chronic pain treatment service for opioid-prescribed individuals completed self-report measures of opioid misuse, alcohol misuse, pain intensity, depression, pain catastrophizing, and post-traumatic stress symptoms (PTS). Based on the substance misuse measures, 32% (n = 68) were misusing neither opioids nor alcohol, 23% (n = 48) were misusing both opioids and alcohol, 40% (n = 84) were misusing opioids alone, and 5% (n = 11) were misusing alcohol alone. Group comparisons indicated that individuals not misusing either substance were less distressed in comparison to those who were misusing opioids alone or both substances. The latter groups differed in PTS. Overall, misuse frequencies mirrored previous work, with approximately 1 of 3 misusing opioids and approximately 1 of 5 misusing both substances. There is a need for increased focus on both polysubstance misuse and the development of integrated treatment.

Sensory-motor response elicited by first time intraoral administered ethanol after trigeminal neuropathic injury

Recent findings have shown a relationship between alcohol use disorders (AUD) and chronic pain. Preclinical models have demonstrated that chronic pain, including trigeminal nerve injury, increases ethanol consumption throughout extended administration periods. Nevertheless, it remains unclear whether chronic pain induces a greater susceptibility to developing AUD by altering motor control consumption regardless of the symptomatology of neuropathic pain and if sex influences this susceptibility. We used a former prolonged pain experience model induced by a constriction of the mental nerve (mNC) to answer this question. We analyzed ethanol consumption in a short access protocol to reduce the post-ingestional effects and compared licking microstructure between groups. The constriction of the mental nerve induced evoked and spontaneous pain and reduction in the hedonic value of sucrose. The differences in alcohol consumption were not reflective of the former prolonged pain experience. Female mice showed a more efficient dynamic of consumption of alcohol reflected in a long burst of licking and a less variable licking rate within a cluster.

Tobacco and cannabis use as moderators of the association between physical activity and alcohol use across the adult lifespan in the United States: NHANES, 2005-2016

Physically-active adults are more likely to consume alcohol, but this association may vary if adults also use other substances (i.e., tobacco and/or cannabis), which could increase substance-use related harms. This study examined whether tobacco and/or cannabis use moderated the associations between physical activity, odds of drinking and alcohol drinks/week. We used cross-sectional 2005-2016 National Health and Nutrition Examination Survey data (United States of America). Physical activity was assessed using device-based and self-reported moderate-to-vigorous physical activity (MVPA) and total physical activity hours/week. Individuals were categorized into one of four (poly)substance use categories, no tobacco/no cannabis, tobacco, cannabis, or tobacco/cannabis use. Regression models examined substance use as a moderator of the association between physical activity and the odds of drinking versus not drinking and alcohol drinks/week among light/moderate/heavy drinkers (≥12 drinks/year). Using cannabis or tobacco weakened the significant positive associations between total physical activity and self-reported recreational MVPA hours/week on odds of drinking (ORs = 0.978 and 0.967, respectively), such that the effect was negative or null when using cannabis or tobacco, respectively. Greater total physical activity and device-based MVPA hours/week was associated with consuming greater drinks/week (IRRs = 1.003 and 1.035, respectively). Using tobacco weakened the association between device-based MVPA and alcohol drinks/week (IRR = 0.934, 95% CI: [0.888, 0.982]). Cannabis and tobacco use weakened the association between physical activity and alcohol use. The positive association between physical activity and alcohol use may be limited to single substance users of alcohol and could reflect shared reasons for engaging in these behaviors, such as stress management or social motives.

Brain Imaging Biomarkers for Chronic Pain

The prevalence of chronic pain has reached epidemic levels. In addition to personal suffering chronic pain is associated with psychiatric and medical co-morbidities, notably substance misuse, and a huge a societal cost amounting to hundreds of billions of dollars annually in medical cost, lost wages, and productivity. Chronic pain does not have a cure or quantitative diagnostic or prognostic tools. In this manuscript we provide evidence that this situation is about to change. We first start by summarizing our current understanding of the role of the brain in the pathogenesis of chronic pain. We particularly focus on the concept of learning in the emergence of chronic pain, and the implication of the limbic brain circuitry and dopaminergic signaling, which underly emotional learning and decision making, in this process. Next, we summarize data from our labs and from other groups on the latest brain imaging findings in different chronic pain conditions focusing on results with significant potential for translation into clinical applications. The gaps in the study of chronic pain and brain imaging are highlighted in throughout the overview. Finally, we conclude by discussing the costs and benefits of using brain biomarkers of chronic pain and compare to other potential markers.

Kappa opioid receptor blockade in the nucleus accumbens shell prevents sex-dependent alcohol deprivation effect induced by inflammatory pain

ABSTRACT

Pain-induced negative affect reduces life quality of patients by increasing psychiatric comorbidities, including alcohol use disorders (AUDs). Indeed, clinical data suggest pain as a risk factor to suffer AUDs, predicting relapse drinking in abstinent patients. Here, we analyse the impact of pain on alcohol relapse and the role of kappa opioid receptor (KOR) activation in mediating these pain-induced effects because KORs play an important role in pain-driven negative affect and AUD. Female and male Sprague-Dawley rats underwent 2 alcohol intermittent access periods separated by a forced abstinence period. The complete Freund adjuvant model of inflammatory pain was introduced during abstinence, and alcohol intake before and after alcohol reintroduction was assessed. In addition, we used behavioural approaches to measure stress and memory impairment and biochemical assays to measure KOR expression in abstinence and reintroduction periods. Only female CFA-treated rats increased alcohol intake during the reintroduction period. Concomitantly, this group showed enhanced anxiety-like behaviour and increased KOR expression in the nucleus accumbens shell that was developed during abstinence and remained during the reintroduction period. Finally, KOR antagonist norbinaltorphimine was administered in the nucleus accumbens shell during abstinence to prevent a pain-induced alcohol deprivation effect, a phenomenon observed in CFA-female rats. The administration of norbinaltorphimine effectively blocked a pain-induced alcohol deprivation effect in female rats. Our data evidenced that inflammatory pain constitutes a risk factor to increase alcohol consumption during a reintroduction phase only in female rats by the rise and maintenance of stress probably mediated by KOR signalling in the nucleus accumbens.

Examining Sex Differences in Associations between Pain and Alcohol Use among College Student-Athletes

Background: College student-athletes are a high-risk population for both pain and alcohol use. Although a growing literature indicates that pain motivates alcohol consumption, no studies have tested associations between pain and alcohol in college student-athletes. Methods and Results: Among National Collegiate Athletic Association Division I student-athletes at a large public university (N = 65; 48% Female), nearly all student-athletes (97%) reported alcohol use and 65% reported pain due to an athletic injury. Pain intensity was positively associated with greater motivation to reduce drinking prior to receiving a brief alcohol intervention. Among females, pain intensity was associated with lower self-reported alcohol consumption. Among male athletes, pain-related interference was associated with greater alcohol-related problems and lower perceived ability to deal with alcohol-related situations. Conclusion: Results provide initial evidence that pain may be important to consider when addressing alcohol use among student-athletes.

Patients with alcohol use disorder increase pain and analgesics use: A nationwide population-based cohort study

BACKGROUND

Alcohol has dual effects on many systems, including the pain system. We will test whether and how chronic alcohol consumption enhances pain sensation to develop pain disorder.

METHODS

We conducted a retrospective matched cohort study using data from the National Health Insurance Research Database (NHIRD) in Taiwan, in patients with and without alcohol use disorder (AUD). This study enrolled 19,174 individuals with AUD as study cohort and 19,174 propensity score-matched individuals without AUD as comparison cohort. The outcome was the incidence of pain disorders and the need for analgesics. The hazard ratios of pain disorders and the need for analgesics were evaluated using Cox proportional hazard regression analysis after adjusting for age, sex, index year, comorbidities, urbanization, areas of residence, and insurance premium.

RESULTS

The 14 years of follow-up showed that AUD patients had a higher adjusted hazard ratio (aHR) for developing pain disorders than in non-AUD controls [aHR= 1.290, 95% confidence interval (CI): 1.045-1.591]. Besides, AUD patients had a higher risk of analgesic use (aHR = 1.081, 95% CI: 1.064-1.312), including opioids and non-opioid analgesics. Most importantly, AUD patients required more days of analgesic use, increased dose of analgesics, and higher costs of analgesics. Moreover, AUD patients had more anemia (aHR=2.772, 95% CI: 2.581-2.872), which could be a mediating factor.

CONCLUSIONS

AUD patients had higher risks of developing pain disorders and subsequently increased analgesic demand. These results suggest that AUD worsened pain, and pain syndrome is correlated with the duration of chronic alcohol exposure.

Alcohol amplifies cingulate cortex signaling and facilitates immobilization-induced hyperalgesia in female rats

Complex Regional Pain Syndrome (CRPS) is a musculoskeletal pain condition that often develops after limb injury and/or immobilization. Although the exact mechanisms underlying CRPS are unknown, the syndrome is associated with central and autonomic nervous system dysregulation and peripheral hyperalgesia symptoms. These symptoms also manifest in alcoholic neuropathy, suggesting that the two conditions may be pathophysiologically accretive. Interestingly, people assigned female at birth (AFAB) appear to be more sensitive to both CRPS and alcoholic neuropathy. To better understand the biobehavioral mechanisms underlying these conditions, we investigated a model of combined CRPS and alcoholic neuropathy in female rats. Animals were pair-fed either a Lieber-DeCarli alcohol liquid diet or a control diet for ten weeks. CRPS was modeled via unilateral hind limb cast immobilization for seven days, allowing for the other limb to serve as a within-subject control for hyperalgesia measures. To investigate the role of circulating ovarian hormones on pain-related behaviors, half of the animals underwent ovariectomy (OVX). Using the von Frey procedure to record mechanical paw withdrawal thresholds, we found that cast immobilization and chronic alcohol drinking separately and additively produced mechanical hyperalgesia observed 3 days after cast removal. We then examined neuroadaptations in AMPA GluR1 and NMDA NR1 glutamate channel subunits, extracellular signal-regulated kinase (ERK), and cAMP response element-binding protein (CREB) in bilateral motor and cingulate cortex across all groups. Consistent with increased pain-related behavior, chronic alcohol drinking increased GluR1, NR1, ERK, and CREB phosphorylation in the cingulate cortex. OVX did not alter any of the observed effects. Our results suggest accretive relationships between CRPS and alcoholic neuropathy symptoms and point to novel therapeutic targets for these conditions.

The Periaqueductal Gray and Its Extended Participation in Drug Addiction Phenomena

The periaqueductal gray (PAG) is a complex mesencephalic structure involved in the integration and execution of active and passive self-protective behaviors against imminent threats, such as immobility or flight from a predator. PAG activity is also associated with the integration of responses against physical discomfort (e.g., anxiety, fear, pain, and disgust) which occurs prior an imminent attack, but also during withdrawal from drugs such as morphine and cocaine. The PAG sends and receives projections to and from other well-documented nuclei linked to the phenomenon of drug addiction including: (i) the ventral tegmental area; (ii) extended amygdala; (iii) medial prefrontal cortex; (iv) pontine nucleus; (v) bed nucleus of the stria terminalis; and (vi) hypothalamus. Preclinical models have suggested that the PAG contributes to the modulation of anxiety, fear, and nociception (all of which may produce physical discomfort) linked with chronic exposure to drugs of abuse. Withdrawal produced by the major pharmacological classes of drugs of abuse is mediated through actions that include participation of the PAG. In support of this, there is evidence of functional, pharmacological, molecular. And/or genetic alterations in the PAG during the impulsive/compulsive intake or withdrawal from a drug. Due to its small size, it is difficult to assess the anatomical participation of the PAG when using classical neuroimaging techniques, so its physiopathology in drug addiction has been underestimated and poorly documented. In this theoretical review, we discuss the involvement of the PAG in drug addiction mainly via its role as an integrator of responses to the physical discomfort associated with drug withdrawal.

Bimodal transcranial direct current stimulation reduces alcohol consumption and induces long-term neurochemical changes in rats with neuropathic pain

This study aimed to evaluate the effects of repeated bimodal transcranial direct current stimulation (tDCS) on alcohol consumption and immunohistological and neurochemical parameters in nerve-injured rats. Forty-eight adult male Wistar rats were distributed into six groups: control, neuropathic pain (NP) + sham-tDCS, NP + alcohol + sham-tDCS, alcohol + sham-tDCS, alcohol + tDCS, and NP + alcohol + tDCS. NP is induced by chronic sciatic nerve constriction (CCI). The rats were exposed to a 10% alcohol solution by voluntary consumption for 14 days. From the 16th day after surgery, bimodal tDCS was applied for 20 min/day for 8 days. Brain structures were collected to evaluate the number of neuropeptide Y (NPY)-positive neurons, neurites, and argyrophilic grains by immunohistochemistry, and brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), interleukin (IL)-6, and IL-10 by ELISA. Nerve-injured rats showed a progressive increase in alcohol consumption compared to the non-injured rats. In addition, there was a reduction in voluntary alcohol consumption over time induced by tDCS. Alcohol exposure, chronic pain, and tDCS treatment modulated the central NPY immunoreactivity. tDCS increased the cerebellar levels of IL-6 and IL-10, and CCI and/or tDCS reduced striatal BDNF levels. The current data suggest that tDCS could be a promising non-pharmacological adjuvant to treat patients with chronic pain who use alcohol to relieve their symptoms.