title: Mokken scaling analysis of the Hospital Anxiety and Depression Scale in individuals with cardiovascular disease.
abstract: OBJECTIVE
  The Hospital Anxiety and Depression Scale (HADS) is a prolifically used scale of anxiety and depression. The original bidimensional anxiety-depression latent structure of the HADS has come under significant scrutiny, with previous studies revealing one-, two-, three- and four-dimensional structures. The current study examines the latent structure of the HADS using a non-parametric item response theory method.
  
  
  METHODS
  Using data conglomerated from four independent studies of cardiovascular disease employing the HADS (n=893), Mokken scaling procedure was conducted to assess the latent structure of the HADS.
  
  
  RESULTS
  A single scale consisting of 12 of 14 HADS items was revealed, indicating a unidimensional latent HADS structure.
  
  
  CONCLUSIONS
  The HADS was initially intended to measure mutually exclusive levels of anxiety and depression; however, the current study indicates that a single dimension of general psychological distress is captured.
authors.affiliation: Division of Population Health Sciences (Psychology), Royal College of Surgeons in Ireland, UK. coscot@tcd.ie
authors.forename: Theodore D
authors.initials: TD
authors.lastname: Cosco
authors.forename: Frank
authors.initials: F
authors.lastname: Doyle
authors.forename: Roger
authors.initials: R
authors.lastname: Watson
authors.forename: Mark
authors.initials: M
authors.lastname: Ward
authors.forename: Hannah
authors.initials: H
authors.lastname: McGee
mesh_terms: D000368:Aged; D001008:Anxiety Disorders / Q000175:diagnosis*; D002318:Cardiovascular Diseases; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000175:diagnosis*; D005260:Female; D006761:Hospitals; D006801:Humans; D007297:Inpatients / Q000523:psychology*; D007494:Ireland; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D011795:Surveys and Questionnaires / Q000592:standards*