We appreciate the interest and comments by Grosset and colleagues regarding our study on the frequency and correlates of ICDs in Parkinson disease. The authors note that in patients who did not take a DA or levodopa, disease duration was likely shorter, reducing their cumulative risk for developing ICDs. Indeed, this patient subset (n = 59) had shorter disease duration than the rest of the study population (median [interquartile range] disease duration, 3.37 [2.37-6.06] years). However, given that disease duration was not associated with ICDs in the entire study population, a possible explanation for the low frequency (1.7%) of ICDs in this group is absence of treatment with dopaminergic therapy at the time of study assessment. Longitudinal studies could investigate this topic directly.
Weintraub D, Fraessdorf M, Potenza MN, Siderowf AD, Stacy M, Voon V, Whetteckey J, Wunderlich GR, Lang AE. Dopamine Agonists vs Levodopa in Impulse Control Disorders—Reply. Arch Neurol. 2011;68(4):544-546. doi:10.1001/archneurol.2011.42