Objective and design: Preclinical studies suggest learned immune system responses to alcohol cues and consumption may contribute to alcohol's pharmacodynamic properties and/or Alcohol Use Disorder (AUD) pathogenesis. Mechanistically, these immune alterations may be associated with increased craving and alcohol consumption, both acutely and over time. We sought to characterize this relationship in a randomized, counter-balanced, crossover neuroimaging experiment which took place between June 2020-November 2021.
Methods: Thirty-three binge drinkers (BD) and 31 non-binge, social drinkers (SD), matched for demographic and psychological variables, were exposed to alcohol cues and water cues in two separate 7 T functional magnetic resonance imaging (fMRI) scans. Each scan was followed by the Alcohol Taste Test (ATT) of implicit motivation for acute alcohol. Craving measures and blood cytokine levels were collected repeatedly during and after scanning to examine the effects of alcohol cues and alcohol consumption on craving levels, Tumor necrosis factor alpha (TNF-α), and Interleukin 6 (IL-6) levels. A post-experiment one-month prospective measurement of participants' "real world" drinking behavior was performed to approximate chronic effects.
Results: BD demonstrated significantly higher peak craving and IL-6 levels than SD in response to alcohol cues and relative to water cues. Ventromedial Prefrontal Cortex (VmPFC) signal change in the alcohol-water contrast positively related to alcohol cue condition craving and IL-6 levels, relative to water cue condition craving and IL-6 levels, in BD only. Additionally, peak craving and IL-6 levels were each independently related to ATT alcohol consumption and the number of drinks consumed in the next month for BD, again after controlling for craving and IL-6 repones to water cues. However, TNF-α release in the alcohol cue condition was not related to craving, neural activation, IL-6 levels, immediate and future alcohol consumption in either group after controlling for water cue condition responses.
Conclusions: In sum, BD show greater craving and IL-6 release in the alcohol cue condition than SD, both of which were associated with prefrontal cue reactivity, immediate alcohol consumption, and future alcohol consumption over the subsequent 30 days. Alcohol associated immune changes and craving effects on drinking behavior may be independent of one another or may be indicative of a common pathway by which immune changes in BD could influence motivation to consume alcohol.
Trial registration: Clinical Trials NCT04412824.
Keywords: Alcohol; Cues; IL-6; TNF-α; fMRI.
© 2023 The Authors.