From Inner Sense to Outer Action: Interoception and Impulsive Compulsive Behavior Disorders in Parkinson's Disease

Background: Impulsive-compulsive behavior disorders (ICBDs) in Parkinson's disease (PD) include impulse control disorders (ICDs) and compulsive behaviors, often linked to dopaminergic treatment and altered reward processing. Interoception, the perception of internal bodily signals, plays a key role in emotional regulation and decision-making. Neuroimaging studies suggest that alterations in interoceptive and reward-related brain circuits may underlie ICDs in PD. However, the relationship between interoception and ICDs remains underexplored. Objective: To investigate the relationship between impulse control disorders (ICD) severity and interoceptive abilities—specifically interoceptive accuracy, insight, and self-reported interoception—in PD patients. Methods: Fifty-one participants were assessed using the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease Rating Scale (QUIP-RS) alongside measures of interoceptive performance, anxiety, depression, and apathy. Results: Higher ICD severity predicted increased interoceptive insight and sensibility. No significant link was found between ICD severity and interoceptive accuracy. Additionally, higher Levodopa Equivalent Daily Dose (LEDD) was related to lower interoceptive insight, suggesting a potential modulatory effect of dopaminergic therapy on meta-cognitive interoception. Conclusions: These findings highlight the complex interplay between ICDs and interoception, suggesting that heightened self-reported interoception and interoceptive insight may reinforce impulsive behaviors in PD via enhanced bodily signal salience. This study contributes to understanding the characteristics of ICDs in PD, implicating reward-related circuits such as the insula and anterior cingulate cortex.