Prevalence of Impulsive-Compulsive Symptoms in Elderly Parkinson's Disease Patients: A Case-Control Study

BACKGROUND: Impulse-control disorders (ICDs) are frequently described in patients with Parkinson's disease (PD), particularly among those treated with dopaminergic medications, but data on the prevalence of ICDs in elderly populations are lacking. OBJECTIVE: The aim of this study was to estimate the prevalence of ICDs by using an Italian validation of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP) and to identify associated sociodemographic and clinical factors in a sample of elderly PD patients and in a control group of similarly aged healthy volunteers. METHODS: Using the United Kingdom Parkinson's Disease Society Brain Bank diagnostic criteria, we included 115 consecutive PD and 105 healthy controls. They were recruited from June 2014 to December 2015. All participants completed the self-administered QUIP-Anytime for assessment of ICDs occurring any time during the course of PD. RESULTS: Mean ± SD age was 75.7 ± 7.0 years in the PD patients and 76.1 ± 7.0 years in the control group. The mean disease duration was 6.8 years (range, 1-26 years). Among the PD patients, 44.7% (n = 51) had at least 1 ICD or related disorder compared to 25.2% (n = 26) in the control group (between-group difference: P = .003). Hypersexuality and compulsive shopping were significantly more common in the PD group than in the control group (P < .05). The prevalence of other compulsive behaviors was 42.5% in the PD group and 38.9% in the control group (P = NS). The Italian version of the QUIP-Anytime showed high test-retest reliability (κ > 0.70 for all items). CONCLUSIONS: Our data confirm a high prevalence of ICD symptoms in elderly PD patients, approximately twice that seen in the general population.