title: Effect of psychiatric and other nonmotor symptoms on disability in Parkinson's disease.
abstract: OBJECTIVE
  To examine the effect of depression and other nonmotor symptoms on functional ability in Parkinson's disease (PD).
  
  
  METHODS
  A cross-sectional study of a convenience sample of PD patients receiving specialty care.
  
  
  METHODS
  The Parkinson's Disease Research, Education and Clinical Center at the Philadelphia Veterans Affairs Medical Center.
  
  
  METHODS
  One hundred fourteen community-dwelling patients with idiopathic PD.
  
  
  METHODS
  The Unified Parkinson's Disease Rating Scale (UPDRS); Hoehn and Yahr Stage; Mini-Mental State Examination; Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, depression module; probes for psychotic symptoms; Hamilton Depression Rating Scale; Geriatric Depression Scale-Short Form; Apathy Scale; and Epworth Sleepiness Scale. Disability was rated using the UPDRS activity of daily living (ADL) score and the Schwab and England ADL score. Multivariate analysis determined effect of depression and other nonmotor symptoms on disability.
  
  
  RESULTS
  The presence of psychosis, depressive disorder, increasing depression severity, age, duration of PD, cognitive impairment, apathy, sleepiness, motor impairment, and percentage of time with dyskinesias were related to greater disability in bivariate analyses. Entering these factors into two multiple regression analyses, only the increasing severity of depression and worsening cognition were associated with greater disability using the UPDRS ADL score, accounting for 37% of the variance in disability (P<.001). These two factors plus increasing severity of PD accounted for 54% of the variance in disability using the Schwab and England ADL score (P<.001).
  
  
  CONCLUSIONS
  Results support and extend previous findings that psychiatric and other nonmotor symptoms contribute significantly to disability in PD. Screening for nonmotor symptoms in PD is necessary to more fully explain functional limitations. Further study is required to determine whether identifying and treating these symptoms will improve function and quality of life.
authors.affiliation: Parkinson's Disease Research, Education and Clinical Center, Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA. weintrau@mail.med.upenn.edu
authors.forename: Daniel
authors.initials: D
authors.lastname: Weintraub
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Moberg
authors.forename: John E
authors.initials: JE
authors.lastname: Duda
authors.forename: Ira R
authors.initials: IR
authors.lastname: Katz
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Stern
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D003071:Cognition; D003072:Cognition Disorders / Q000175:diagnosis; D003430:Cross-Sectional Studies; D003863:Depression / Q000175:diagnosis* / Q000209:etiology / Q000523:psychology; D004185:Disability Evaluation; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D010300:Parkinson Disease / Q000175:diagnosis / Q000523:psychology; D011569:Psychiatric Status Rating Scales; D011788:Quality of Life