title: Diagnostic accuracy of case-finding questions to identify perinatal depression.
abstract: BACKGROUND
  Guidelines for perinatal mental health care recommend the use of two case-finding questions about depressed feelings and loss of interest in activities, despite the absence of validation studies in this context. We examined the diagnostic accuracy of these questions and of a third question about the need for help asked of women receiving perinatal care.
  
  
  METHODS
  We evaluated self-reported responses to two case-finding questions against an interviewer-assessed diagnostic standard (DSM-IV criteria for major depressive disorder) among 152 women receiving antenatal care at 26-28 weeks' gestation and postnatal care at 5-13 weeks after delivery. Among women who answered "yes" to either question, we assessed the usefulness of asking a third question about the need for help. We calculated sensitivity, specificity and likelihood ratios for the two case-finding questions and for the added question about the need for help.
  
  
  RESULTS
  Antenatally, the two case-finding questions had a sensitivity of 100% (95% confidence interval [CI] 77%-100%), a specificity of 68% (95% CI 58%-76%), a positive likelihood ratio of 3.03 (95% CI 2.28-4.02) and a negative likelihood ratio of 0.041 (95% CI 0.003-0.63) in identifying perinatal depression. Postnatal results were similar. Among the women who screened positive antenatally, the additional question about the need for help had a sensitivity of 58% (95% CI 38%-76%), a specificity of 91% (95% CI 78%-97%), a positive likelihood ratio of 6.86 (95% CI 2.16-21.7) and a negative likelihood ratio of 0.45 (95% CI 0.25-0.80), with lower sensitivity and higher specificity postnatally.
  
  
  CONCLUSIONS
  Negative responses to both of the case-finding questions showed acceptable accuracy for ruling out perinatal depression. For positive responses, the use of a third question about the need for help improved specificity and the ability to rule in depression.
authors.affiliation: Department of Health Sciences, University of York, York, United Kingdom. rcm504@york.ac.uk
authors.forename: Rachel
authors.initials: R
authors.lastname: Mann
authors.forename: Joy
authors.initials: J
authors.lastname: Adamson
authors.forename: Simon M
authors.initials: SM
authors.lastname: Gilbody
mesh_terms: D000328:Adult; D019052:Depression, Postpartum / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D007406:Interview, Psychological / Q000379:methods; D018743:Perinatal Care / Q000379:methods; D011569:Psychiatric Status Rating Scales; D057566:Self Report; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires