title: Modeling anxiety in Parkinson's disease.
abstract: BACKGROUND
  The aim of this work was to construct a model for anxiety in PD and compare the relative contributions of PD-specific and -nonspecific general population risk factors for anxiety in this model.
  
  
  METHODS
  Structural equation modeling of associations of risk factors with the anxiety outcome using a cross-sectional data set of 342 patients with PD were used.
  
  
  RESULTS
  A model with acceptable to good fit was generated that explained 65% of the variance in anxiety scores. A previous history of depression and the severity of the depressive symptoms scored on the Hamilton Depression Rating Scale were the only nonspecific variables with a direct effect on anxiety. The presence of motor fluctuations and disease-related decline in activities of daily living were PD-specific markers of anxiety. Nonspecific risk factors had a greater influence in the model than PD-specific risk factors. Standardized regression coefficients suggested that the Hamilton Depression Rating Scale score was the most important contributor to the variation in anxiety. A post-hoc analysis showed that the effects of the following variables on anxiety levels were fully mediated by depression: sex; family history of depression; previous history of anxiety; cognitive status; difficulties in non-disease-specific activities of daily living; and severity of motor signs.
  
  
  CONCLUSIONS
  In this cross-sectional study, we showed that nonspecific general population risk factors are more important markers for anxiety than PD-specific risk factors. Depression was the most prominent marker. PD-specific markers for anxiety appear to be more situational and related to off periods and disease-specific disturbances of activities of daily living.
authors.affiliation: Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Martijn P G
authors.initials: MP
authors.lastname: Broen
authors.affiliation: Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Alzheimer Center Limburg, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Köhler
authors.affiliation: Department of Psychiatry, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Anja J H
authors.initials: AJ
authors.lastname: Moonen
authors.affiliation: Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Kuijf
authors.affiliation: Neurology and Movement Disorders Unit, Lille University Medical Center, Lille, France.
authors.forename: Kathy
authors.initials: K
authors.lastname: Dujardin
authors.affiliation: Departments of Psychiatry and Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Marsh
authors.affiliation: Departments of Neurology and Department of Psychiatry, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA.
authors.forename: Irene H
authors.initials: IH
authors.lastname: Richard
authors.affiliation: School of Psychiatry, University of Western Australia and Fremantle Hospital, Fremantle, Western Australia, Australia.
authors.forename: Sergio E
authors.initials: SE
authors.lastname: Starkstein
authors.affiliation: Area of Applied Epidemiology, National Center for Epidemiology, and CIBERNED, Carlos III Institute of Health, Madrid, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Martinez-Martin
authors.affiliation: Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Alzheimer Center Limburg, Maastricht University Medical Center, Maastricht, The Netherlands.|Department of Psychiatry, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Albert F G
authors.initials: AF
authors.lastname: Leentjens
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology*; D000328:Adult; D000368:Aged; D001007:Anxiety / Q000523:psychology*; D001008:Anxiety Disorders / Q000523:psychology*; D003430:Cross-Sectional Studies; D003863:Depression / Q000523:psychology*; D003866:Depressive Disorder / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000523:psychology*; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors
keywords: Parkinson's disease; anxiety; depression; model; risk factor