Questionnaire for impulsive‐compulsive disorders in Parkinson's Disease–Rating Scale

Impulse control disorders and related disorders (hobbyism‐punding and dopamine dysregulation syndrome) occur in 15% to 20% of Parkinson's disease (PD) patients. We assessed the validity and reliability of the Questionnaire for Impulsive‐Compulsive Disorders in Parkinson's Disease–Rating Scale (QUIP‐RS), a rating scale designed to measure severity of symptoms and support a diagnosis of impulse control disorders and related disorders in PD. A convenience sample of PD patients at a movement disorders clinic self‐completed the QUIP‐RS and were administered a semistructured diagnostic interview by a blinded trained rater to assess discriminant validity for impulse control disorders (n = 104) and related disorders (n = 77). Subsets of patients were assessed to determine interrater reliability (n = 104), retest reliability (n = 63), and responsiveness to change (n = 29). Adequate cutoff points (both sensitivity and specificity values >80% plus acceptable likelihood ratios) were established for each impulse control disorder and hobbyism‐punding. Interrater and retest reliability (intraclass correlation coefficient r ) were >0.60 for all disorders. Participants in an impulse control disorder treatment study who experienced full ( t = 3.65, P = .004) or partial ( t = 2.98, P = .01) response demonstrated significant improvement on the rating scale over time, while nonresponders did not ( t = 0.12, P = .91). The QUIP‐RS appears to be valid and reliable as a rating scale for impulse control disorders and related disorders in PD. Preliminary results suggest that it can be used to support a diagnosis of these disorders, as well as to monitor changes in symptom severity over time. © 2011 Movement Disorder Society