title: Impact of Depression on Progression of Impairment and Disability in Early Parkinson's Disease.
abstract: BACKGROUND
  Depression is one of the most common nonmotor symptoms associated with Parkinson's disease (PD), yet the impact of depression on progression of disease is unclear.
  
  
  OBJECTIVE
  The aim of this study was to prospectively characterize the relationship between depressive symptoms and measures of disease progression in a large sample of patients with early, medically treated PD.
  
  
  METHODS
  Baseline and longitudinal Beck Depression Inventory (BDI) scores from participants in the NINDS Exploratory Trials in PD Long Term Study 1 were correlated with changes in multiple measures of disease severity over 5 years. Multivariate analysis of predictors of change in BDI was performed.
  
  
  RESULTS
  Of 1,741 participants, 746 completed 5-year assessments and were included. Mean age was 62.00 years (standard deviation [SD]: 9.22) and mean disease duration was 1.69 years (SD, 1.16). Mean BDI score was 6.24 (SD, 5.02) at baseline and 8.57 (SD, 6.60) at 5 years. Baseline BDI score was strongly associated with rate of change in all examined measures of disease severity. In multivariate analysis, BDI 5-year change was associated with change in UPDRS Part I (excluding depression item;P< 0.01), 33-item Parkinson's Disease Questionnaire (P< 0.01), EuroQOL Five Dimensional Questionnaire (P= 0.02), and Total Functional Capacity (P< 0.01), but was not associated with motor or cognitive measures. This model explained 68.8% of the variance 5-year change of the BDI score.
  
  
  CONCLUSIONS
  Worse baseline BDI scores are associated with a decline in multiple measures of disease severity in PD. Worsening of BDI at 5 years was associated with worsening in UPDRS Part I and quality-of-life measures, but not with motor or cognitive measures.
authors.affiliation: Northwestern University, Chicago, Illinois, USA.
authors.forename: Danny
authors.initials: D
authors.lastname: Bega
authors.affiliation: University of Texas Health Science Center, Houston, Texas, USA.
authors.forename: Sheng
authors.initials: S
authors.lastname: Luo
authors.affiliation: Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Hubert
authors.initials: H
authors.lastname: Fernandez
authors.affiliation: University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Kelvin
authors.initials: K
authors.lastname: Chou
authors.affiliation: University of California San Francisco, San Francisco, California, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Aminoff
authors.affiliation: Minneapolis Clinic, Minneapolis, Minnesota, USA.
authors.forename: Sotirios
authors.initials: S
authors.lastname: Parashos
authors.affiliation: University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: Harrison
authors.initials: H
authors.lastname: Walker
authors.affiliation: Institute for Neurodegenerative Disorders, New Haven, Connecticut, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Russell
authors.affiliation: University of California San Francisco, San Francisco, California, USA.
authors.forename: Chadwick W
authors.initials: CW
authors.lastname: Christine
authors.affiliation: Muhammad Ali Parkinson Center, Phoenix, Arizona, USA.
authors.forename: Rohit
authors.initials: R
authors.lastname: Dhall
authors.affiliation: University of Miami, Miami, Florida, USA.
authors.forename: Carlos
authors.initials: C
authors.lastname: Singer
authors.affiliation: State University of New York, Syracuse, New York, USA.
authors.forename: Ivan
authors.initials: I
authors.lastname: Bodis-Wollner
authors.affiliation: University of Vermont, Burlington, Vermont, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Hamill
authors.affiliation: Parkinson and Movement Disorders Institute, Fountain Valley, California, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Truong
authors.affiliation: Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Mari
authors.affiliation: State University of New York, Syracuse, New York, USA.
authors.forename: Sofya
authors.initials: S
authors.lastname: Glazmann
authors.affiliation: University of Texas Health Science Center, Houston, Texas, USA.
authors.forename: Meilin
authors.initials: M
authors.lastname: Huang
authors.affiliation: University of Vermont, Burlington, Vermont, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Houston
authors.affiliation: Northwestern University, Chicago, Illinois, USA.
authors.forename: Tanya
authors.initials: T
authors.lastname: Simuni
keywords: NET-PD; Parkinson’s disease; beck depression inventory; depression