Acute Tolerance to the Analgesic Effects of Alcohol

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.

Alcohol Use Disorder and Chronic Pain: An Overlooked Epidemic

Alcohol use disorder (AUD) and chronic pain disorders are pervasive, multifaceted medical conditions that often co-occur. However, their comorbidity is often overlooked, despite its prevalence and clinical relevance. Individuals with AUD are more likely to experience chronic pain than the general population. Conversely, individuals with chronic pain commonly alleviate their pain with alcohol, which may escalate into AUD. This narrative review discusses the intricate relationship between AUD and chronic pain. Based on the literature available, the authors present a theoretical model explaining the reciprocal relationship between AUD and chronic pain across alcohol intoxication and withdrawal. They propose that the use of alcohol for analgesia rapidly gives way to acute tolerance, triggering the need for higher levels of alcohol consumption. Attempts at abstinence lead to alcohol withdrawal syndrome and hyperalgesia, increasing the risk of relapse. Chronic neurobiological changes lead to preoccupation with pain and cravings for alcohol, further entrenching both conditions. To stimulate research in this area, the authors review methodologies to improve the assessment of pain in AUD studies, including self-report and psychophysical methods. Further, they discuss pharmacotherapies and psychotherapies that may target both conditions, potentially improving both AUD and chronic pain outcomes simultaneously. Finally, the authors emphasize the need to manage both conditions concurrently, and encourage both the scientific community and clinicians to ensure that these intertwined conditions are not overlooked given their clinical significance.

Expectancy of alcohol analgesia moderates perception of pain relief following acute alcohol intake

Although laboratory studies indicate alcohol reduces pain intensity and increases pain threshold, these effects likely do not completely explain perceived pain relief from alcohol intake. In this study, we tested expectancy of alcohol analgesia (EAA) as a moderator of subjective pain relief following oral alcohol challenge in individuals with and without chronic orofacial pain. Social drinkers (N = 48; 19 chronic pain; 29 pain-free controls) completed two testing sessions: alcohol administration (BrAC: 0.08 g/dL) and placebo. Alcohol expectancy (AE) was assessed using the EAA questionnaire and two 100-mm Visual Analogue Scales (VASs) regarding strength of belief that alcohol provides pain relief (AE VAS 1) or reduces pain sensitivity (AE VAS 2). Participants completed quantitative sensory testing (QST) involving application of pressure to the masseter insertion. Pain threshold (lbf; three repetitions) and pain intensity (4, 5, and 6 lbf; three repetitions each; 100-mm VAS) were collected. After each stimulus, participants rated perceived pain relief due to consumption of the study beverage (0-100 VAS). Higher EAA and AE VAS 1 ratings were associated with stronger perceived relief in the alcohol, but not placebo, condition. However, expectancy specifically related to reduction in pain sensitivity (AE VAS 2) was not associated with relief. Additionally, changes in pain threshold and intensity were not significantly correlated with perceived relief. Taken together, results suggest expectancy that alcohol provides pain relief is an important determinant of its negative reinforcing effects. Future studies should investigate challenging these expectancies as a means of reducing alcohol-related risk in people with pain. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

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).

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.

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.