Interoceptive awareness is associated with acute alcohol-induced changes in subjective effects

Interoception, the sensing of bodily signals, is related to emotional reactivity and may contribute to the pathophysiology of addiction. Evidence is accumulating that individuals with alcohol use disorders and other substance-dependences show altered interoceptive processing, however little is known about the acute effects of alcohol on interoception and how this may influence the perception of drug induced effects. In a double-blind design, fifty (30 females) healthy young participants were given a beverage containing either a low (0.4 g/kg, n = 18) or high (0.6 g/kg, n = 15) alcohol dose or a placebo (n = 17). After alcohol administration, participants completed two interoceptive paradigms, the heart-beat tracking and heart-beat discrimination tasks, both assessing different accuracy and metacognitive measures of interoception. Subjective feelings elicited by alcohol administration were also measured. Participants under the low alcohol dose had lower metacognitive interoceptive awareness on the discrimination task compared to placebo. Participants under alcohol experienced feelings of light-headedness, which were positively associated with increased interoceptive awareness in the cardiac discrimination task. These results provide evidence for a relationship between interoceptive processing and the perception of drug-induced mood changes. This finding, showing how interoceptive awareness of cardiac discrimination contributes to the appraisal of subjective light-headedness generated by alcohol administration, brings novel perspectives to the understanding of drug discrimination and reinforcement mechanisms.