title: Incident impulse control disorder symptoms and dopamine transporter imaging in Parkinson disease.
abstract: OBJECTIVE
  To describe the incidence of, and clinical and neurobiological risk factors for, new-onset impulse control disorder (ICD) symptoms and related behaviours in early Parkinson disease (PD).
  
  
  METHODS
  The Parkinson's Progression Markers Initiative is an international, multicenter, prospective study of de novo patients with PD untreated at baseline and assessed annually, including serial dopamine transporter imaging (DAT-SPECT) and ICD assessment (Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease short form, QUIP). Participants were included if they screened negative on the QUIP at baseline. Kaplan-Meier curves and generalised estimating equations examined frequency and predictors of incident ICD symptoms.
  
  
  RESULTS
  Participants were seen at baseline (n=320), year 1 (n=284), year 2 (n=217) and year 3 (n=96). Estimated cumulative incident rates of ICD symptoms and related behaviours were 8% (year 1), 18% (year 2) and 25% (year 3) and increased each year in those on dopamine replacement therapy (DRT) and decreased in those not on DRT. In participants on DRT, risk factors for incident ICD symptoms were younger age (OR=0.97, p=0.05), a greater decrease in right caudate (OR=4.03, p=0.01) and mean striatal (OR=6.90, p=0.04) DAT availability over the first year, and lower right putamen (OR=0.06, p=0.01) and mean total striatal (OR=0.25, p=0.04) DAT availability at any post-baseline visit.
  
  
  CONCLUSIONS
  The rate of incident ICD symptoms increases with time and initiation of DRT in early PD. In this preliminary study, a greater decrease or lower DAT binding over time increases risk of incident ICD symptoms, conferring additional risk to those taking DRT.
  
  
  BACKGROUND
  NCT01141023.
authors.affiliation: Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Kara M
authors.initials: KM
authors.lastname: Smith
authors.affiliation: Department of Biostatistics and Epidemiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Sharon X
authors.initials: SX
authors.lastname: Xie
authors.affiliation: Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA Parkinson's Disease Research, Education and Clinical Centers (PADRECC), Philadelphia Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA Mental Illness Research, Education and Clinical Centers (MIRECC), Philadelphia Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Weintraub
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D002421:Caudate Nucleus / Q000378:metabolism; D003342:Corpus Striatum / Q000378:metabolism; D018450:Disease Progression; D007174:Disruptive, Impulse Control, and Conduct Disorders / Q000139:chemically induced* / Q000150:complications / Q000175:diagnosis / Q000378:metabolism; D018491:Dopamine Agonists / Q000009:adverse effects*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000188:drug therapy / Q000378:metabolism*; D011446:Prospective Studies; D012307:Risk Factors; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D015415:Biomarkers; D018491:Dopamine Agonists; D050483:Dopamine Plasma Membrane Transport Proteins