Clinical characteristics of impulse control and repetitive behavior disorders in Parkinson's disease

Impulse control and repetitive behavior disorders (ICRBs) are a group of diseases including impulse control disorder (ICD), repetitive behavior disorder (RB), and dopamine dysregulation syndrome (DDS). This study determined the prevalence and associated characteristics of ICRBs in Parkinson's disease (PD) patients. Included were 297 patients, interviewed with the questionnaire for impulsive-compulsive disorders in PD for screening of various ICRBs. Questionnaire results and clinical characteristics were analyzed. The ICRB prevalence among PD patients was 15.5 % (46 of 297), with 35 patients with ICD, 20 with RB, and 7 with DDS. Patients with ICRB were predominantly male, younger, taking higher doses of dopaminergic drugs, and had longer disease duration, worse Unified Parkinson's Disease Rating Scale (UPDRS) motor score, and worse PD quality of life questionnaire score. However, each ICRB subtype had different risk factor profiles. ICD patients were predominantly male, younger, had longer disease duration, were affected by PD from young age, were taking higher total dopaminergic drug dosages, and had more RB. RB patients had higher UPDRS part III scores, were taking higher levodopa doses, and had higher comorbid ICD. DDS patients were taking higher dopamine agonist doses, and had more frequent ICD. In multivariate logistic regression for secondary analysis, only younger age and comorbid RB or DDS showed significant association with ICD and only poor UPDRS III score and comorbid ICD were significantly associated with RB. These findings suggested that different risk factors contribute to development of each ICRB subtype. ICRB could be a combination of heterogeneous disease entities that need to be treated separately.