Differences in Interoceptive Characteristics Between Individuals with Heroin and Methamphetamine Use Disorder and Their Association with Anxiety Symptoms

BACKGROUND: Anxiety symptoms are prevalent in individuals with substance use disorders (SUDs) and significantly impact treatment outcomes and relapse risk. Recent evidence points to dysregulated interoceptive processing as a potential mechanism underlying anxiety in SUDs. This dysfunction may vary across substances due to their distinct pharmacological profiles. However, direct comparisons of multidimensional interoceptive profiles between different substance addictions and their links to anxiety remain limited. METHODS: a heartbeat tracking task, interoceptive awareness by correlating confidence ratings with performance, and interoceptive sensibility using the Multidimensional Assessment of Interoceptive Awareness. Anxiety was assessed with the State-Trait Anxiety Inventory-State subscale. Group comparisons, Pearson correlations, and multiple regression were conducted to examine links between interoceptive measures and anxiety and to test whether addiction type moderated these associations. RESULTS: Both groups showed reduced interoceptive sensibility (trust, non-distracting) vs. controls, but only the HUD group had significantly poorer interoceptive accuracy. Lower accuracy was uniquely linked to higher anxiety in HUD, whereas in MUD, anxiety correlated mainly with diminished bodily trust and self-regulation. Regression confirmed that anxiety predictors differed by substance type, with a significant IAcc × addiction type interaction. CONCLUSION: Individuals with SUDs show substance-specific interoceptive impairments, which are differentially linked to anxiety. Interoceptive accuracy appears to be a key marker for anxiety in heroin addiction. These findings underscore the clinical potential of targeting interoceptive processes to reduce anxiety in SUDs.