title: Validation of the PHQ-15 for somatoform disorder in the occupational health care setting.
abstract: BACKGROUND
  Within the occupational health setting, somatoform disorders are a frequent cause of sick leave. Few validated screening questionnaires for these disorders are available. The aim of this study is to validate the PHQ-15 in this setting.
  
  
  METHODS
  In a cross-sectional study of 236 sicklisted employees, we studied the performance of the PHQ-15 in comparison with the Mini International Neuropsychiatric Interview (MINI) as golden reference standard. We approached employees who were sick listed for a period longer than 6 weeks and shorter than 2 years for participation. This study was conducted on one location of a large occupation health service in the Netherlands, serving companies with more than 500 employees. All employees who returned the PHQ-15 were invited for the MINI interview. Specificity and sensitivity were calculated for optimal cut point and a receiver operating characteristic (ROC) was constructed.
  
  
  RESULTS
  A total of 107 participants consented to participate in the MINI interview. A non-response analysis showed no significant differences between groups. According to the MINI, the prevalence of somatoform disorders was 21.5%, and the most frequent found disorder was a pain disorder. The PHQ-15 had an optimal cut point of 9 (patients scoring 9 or higher (≥9) were most likely to suffer from a somatoform disorder), with specificity and sensitivity equal to 61.9 and 56.5%, respectively. ROCs showed an area under the curve (AUC) of 0.63.
  
  
  CONCLUSIONS
  The PHQ-15 shows moderate sensitivity but limited efficiency with a cut point of 9 and can be a useful questionnaire in the occupational health setting.
authors.affiliation: Trimbos Institute, Netherlands Institute of Mental Health and Addiction, Utrecht, The Netherlands. l.vroege@trimbos.nl
authors.forename: Lars
authors.initials: L
authors.lastname: de Vroege
authors.forename: Rob
authors.initials: R
authors.lastname: Hoedeman
authors.forename: Jasper
authors.initials: J
authors.lastname: Nuyen
authors.forename: Klaas
authors.initials: K
authors.lastname: Sijtsma
authors.forename: Christina M
authors.initials: CM
authors.lastname: van der Feltz-Cornelis
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D008403:Mass Screening / Q000295:instrumentation* / Q000706:statistics & numerical data; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D016272:Occupational Health; D009786:Occupational Health Services; D015995:Prevalence; D012680:Sensitivity and Specificity; D012959:Socioeconomic Factors; D013001:Somatoform Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D011795:Surveys and Questionnaires