Impulsive and compulsive parkin disease

Abstract

In this issue of Neurology ®, Morgante et al.1 present a nice genotype–phenotype study of parkin -associated Parkinson disease (PD). PD is a progressive neurodegenerative disorder that affects 4.1 to 4.6 million people worldwide2 and results in motor dysfunction and nonmotor symptoms including psychiatric problems. Impulse control disorder (ICD) is one such psychiatric problem that may present in PD. These impulsive behaviors are diverse and include excessive shopping, hypersexuality, binge-eating behavior, and pathologic gambling.3,4 The incidence of ICDs is higher in patients with PD who have been treated with long-term dopaminergic replacement therapy including dopamine agonists, levodopa, and amantadine. Increasing evidence suggests that higher levodopa equivalent daily dose, male sex, younger age at PD onset, history of alcoholism, history of smoking, family history of gambling problems, and novelty-seeking personality are risk factors of ICD.4 In addition, imaging studies propose potential neural networks that may underlie impulsivity and ICDs in PD.5 The prevalence of ICD in treated PD can be up to 35%.6 However, in routine clinical practice, ICDs are often diagnosed late or remain undiagnosed and untreated. The authors thank Drs. Bill Dauer, Conor Fearon, John Krakauer, Diana Olszewska, and Eavan McGovern for their very helpful discussion and advice in drafting this editorial.