title: The role of comorbidity in the detection of psychiatric disorders with checklists for mental and physical symptoms in primary care.
abstract: OBJECTIVE
  To examine the contribution of a mental and physical symptom count to the detection of single or comorbid anxiety, depressive and somatoform disorders.
  
  
  METHODS
  In primary care 1,046 consulting patients completed the Hospital Anxiety and Depression Scale (HADS) and the Physical Symptom Checklist (PSC-51). In a stratified sample of 473 patients DSM-IV psychiatric disorders were assessed using the WHO-SCAN interview. The diagnostic value of the HADS total score and the PSC-51 symptom count was examined with ROC-analyses.
  
  
  RESULTS
  The discriminative power of PSC-51 and HADS was highest for patients with both a somatoform disorder and an anxiety or depressive disorder, with an AUC of 0.86 (95% CI: 0.81-0.91) and 0.91 (95% CI: 0.87-0.94) respectively. Using both symptom counts together did not increase the diagnostic value for the detection of the psychiatric disorders.
  
  
  CONCLUSIONS
  Both symptom counts preferentially detected patients with comorbid disorders. When interpreting diagnostic values of screening questionnaires one should keep in mind that the validity of these values can be dependent of the presence of comorbid disorders.
authors.affiliation: Department of Public Health and Primary Care, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands. m.w.m.de_waal@lumc.nl
authors.forename: Margot W M
authors.initials: MW
authors.lastname: de Waal
authors.forename: Ingrid A
authors.initials: IA
authors.lastname: Arnold
authors.forename: Philip
authors.initials: P
authors.lastname: Spinhoven
authors.forename: Just A H
authors.initials: JA
authors.lastname: Eekhof
authors.forename: Willem J J
authors.initials: WJ
authors.lastname: Assendelft
authors.forename: Albert M
authors.initials: AM
authors.lastname: van Hemert
mesh_terms: D000328:Adult; D000342:Affective Symptoms / Q000175:diagnosis* / Q000453:epidemiology; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D003863:Depression / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis* / Q000453:epidemiology; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011320:Primary Health Care; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D012372:ROC Curve; D017678:Sex Distribution