Pathological gambling is an impulse control disorder reported in association with dopamine agonists used to treat Parkinson's disease. Although impulse control disorders are conceptualized as lying within the spectrum of addictions, little neurobiological evidence exists to support this belief. Functional imaging studies have consistently demonstrated abnormalities of dopaminergic function in patients with drug addictions, but to date no study has specifically evaluated dopaminergic function in Parkinson's disease patients with impulse control disorders. We describe results of a [(11)C] raclopride positron emission tomography (PET) study comparing dopaminergic function during gambling in Parkinson's disease patients, with and without pathological gambling, following dopamine agonists. Patients with pathological gambling demonstrated greater decreases in binding potential in the ventral striatum during gambling (13.9%) than control patients (8.1%), likely reflecting greater dopaminergic release. Ventral striatal bindings at baseline during control task were also lower in patients with pathological gambling. Although prior imaging studies suggest that abnormality in dopaminergic binding and dopamine release may be markers of vulnerability to addiction, this study presents the first evidence of these phenomena in pathological gambling. The emergence of pathological gambling in a number of Parkinson's disease patients may provide a model into the pathophysiology of this disorder.

We surveyed 297 patients with Parkinson disease (PD) with systematic screens and rigorous definitional criteria. Pathologic hypersexuality lifetime prevalence was 2.4%. Compulsive shopping was 0.7%. Combined with our pathologic gambling data, the lifetime prevalence of these behaviors was 6.1% and increases to 13.7% in patients on dopamine agonists.

Patients: Twenty-one patients with idiopathic PD with PG after the patients began receiving medications compared with a consecutive sample of 42 patients with idiopathic PD without compulsive behaviors.Main Outcome Measures: Clinical features, comorbid psychiatric and substance use disorders, personality traits, and impulsivity scores.Results: Patients with PG had a younger age at PD onset (P=.006), higher novelty seeking (PϽ.001), medication-induced hypomania or mania (P =.001), impaired planning (P=.002), or a personal or immediate family history of alcohol use disorders (P = .002). Novelty seeking, a personal or immediate family history of alcohol use disorders, and younger age at PD onset accurately predicted PG at 83.7% in a logistic regression model, with the model accounting for 62% of the variance.Conclusions: Patients with PD having a younger age at PD onset, higher novelty seeking traits, and a personal or family history of alcohol use disorders may have a greater risk for PG with dopamine agonists.

The authors prospectively screened 297 patients with Parkinson disease (PD), who attended a tertiary clinic, using a modified South Oaks Gambling Scale. Lifetime prevalence of pathologic gambling (PG) was 3.4% and on any dopamine agonist was 7.2%. PG was associated with earlier PD onset and with dopamine agonists but not with agonist subtype or doses. We found no association with a potent D3 receptor agonist.

P arkinson disease is chronic and progressive in nature, decreasing the quality of life for both patients with the disease and their caregivers and placing an onerous economic burden on society. 1 The first Canadian guideline on Parkinson disease was published in 2012. 2 Since that guideline, there have been substantial advances in the literature on the disease, particularly with respect to diagnostic criteria and treatment options. Parkinson Canada undertook to update the existing guideline to reflect these advances, as well as to add information on palliative care. With the aim of enhancing care for all Canadians with Parkinson disease, this guideline is based on the best published evidence, involves expert consensus when there is a lack of evidence, offers practical clinical advice, takes patient choice and informed decision-making into account and is relevant to the Canadian health care system. The guideline has been divided into 5 main sections to improve the ease of use: communication, diagnosis and progression, treatment, nonmotor features and palliative care. The full guideline is available in Appendix 1, at www.cmaj.ca/lookup/ suppl/