title: Utility of the twelve-item World Health Organization Disability Assessment Schedule II (WHO-DAS II) for discriminating depression "caseness" and severity in Spanish primary care patients.
abstract: OBJECTIVE
  The 12-item WHO-DAS II was developed to assess the activity limitations and participation restrictions experienced by individuals irrespective of medical diagnosis. In this paper we examine the known-groups' validity of the instrument by evaluating its ability to discriminate between patients with/without major depression, patients with depression with/without medical comorbidity, and patients with depression with different depression severity.
  
  
  METHODS
  The participants were 3,615 PC patients from 17 regions of Spain, with a first-time diagnosis of major depressive episode according to the general practitioner. The 12-item WHO-DAS II, the PHQ-9, and a chronic medical conditions checklist were administered during the consultation.
  
  
  RESULTS
  The statistical analyses indicated that the 12-item WHO-DAS II was able to discriminate between patients with/without depression and between those with different depression severity. The ROC analysis revealed that with a cutoff score >or=50, the instrument correctly classified 70.4% of the sample (area under the ROC curve = .76; sensitivity = 71.4%; specificity = 67.6%).
  
  
  CONCLUSIONS
  Overall, our results support the discriminant validity of the 12-item WHO-DAS II for major depression, being quite recommendable its use in epidemiological research.
authors.affiliation: Parc Sanitari Sant Joan de Déu, Fundació Sant Joan de Déu, Sant Boi de Llobregat, Barcelona, Spain. jvluciano@sjd-ssm.com
authors.forename: Juan V
authors.initials: JV
authors.lastname: Luciano
authors.forename: José L
authors.initials: JL
authors.lastname: Ayuso-Mateos
authors.forename: Ana
authors.initials: A
authors.lastname: Fernandez
authors.forename: Jaume
authors.initials: J
authors.lastname: Aguado
authors.forename: Antoni
authors.initials: A
authors.lastname: Serrano-Blanco
authors.forename: Miquel
authors.initials: M
authors.lastname: Roca
authors.forename: Josep M
authors.initials: JM
authors.lastname: Haro
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D003866:Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology; D003865:Major Depressive Disorder / Q000145:classification* / Q000175:diagnosis* / Q000453:epidemiology; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care / Q000379:methods*; D011594:Psychometrics; D011788:Quality of Life; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013030:Spain / Q000453:epidemiology; D014944:World Health Organization