Abstract
Background
Impulse control disorders (ICDs) are clinically relevant non-motor complications of Parkinson’s disease (PD). ICDs include gambling, hypersexuality, compulsive shopping, binge eating, hobbyism/punding, and dopamine dysregulation syndrome. Although dopaminergic replacement therapies are a key risk factor, only a subgroup of treated patients develop ICDs, potentially suggesting that neuropsychological differences may contribute to interindividual variability. Dysfunctional Metacognitive Beliefs (MBs) have recently been associated with addictive behaviors in the general population, but their role in neurologically driven addictive-like behaviors has not yet been examined. This exploratory study aimed to investigate whether dysfunctional MBs are associated with ICD symptom severity in PD patients after controlling for variables of dopaminergic exposure.
Methods
38 PD patients (44.7% F, mean age 67.55) completed the Metacognitions Questionnaire-30 (MCQ-30) and the Questionnaire for Impulsive-Compulsive Disorders in Parkinson’s Disease-Rating Scale (QUIP-RS). One-sample t-tests were used to compare MCQ scores with normative values from the Italian general community sample. Two-tailed partial correlations tested associations between MCQ-30 scores and QUIP-RS outcomes, controlling for treatment duration, dopamine agonist exposure (LEDD-DA), and other dopaminergic exposures (i.e., total LEDD minus LEDD-DA). Additionally, independent samples t-tests were conducted to compare MCQ-30 scores between patients with and without ICDs. False discovery rate correction was applied.
Results
Overall, 23.7% of patients exceeded the QUIP-ICD cut-off. Compared with normative data from the general community sample, PD patients showed a more dysfunctional metacognitive profile. After controlling for dopaminergic exposure, ICD symptom severity was associated with positive beliefs about worry, negative beliefs about uncontrollability and danger, reduced cognitive confidence, greater need to control thoughts, and lower cognitive self-consciousness. In group comparisons, patients exceeding the QUIP-ICD cut-off showed significantly higher MCQ-POS, MCQ-NEG, and MCQ-NC scores and lower MCQ-CSC scores than those below the cut-off.
Discussion
These exploratory findings suggest that, after controlling for dopaminergic variables, dysfunctional MBs are associated with ICD symptom severity. In this context, MBs may represent one of the cognitive-affective correlates of ICD interindividual variability.