title: Using the Patient Health Questionnaire-9 to measure depression among racially and ethnically diverse primary care patients.
abstract: OBJECTIVE
  The Patient Health Questionnaire depression scale (PHQ-9) is a well-validated, Diagnostic and Statistical Manual of Mental Disorders- Fourth Edition (DSM-IV) criterion-based measure for diagnosing depression, assessing severity and monitoring treatment response. The performance of most depression scales including the PHQ-9, however, has not been rigorously evaluated in different racial/ethnic populations. Therefore, we compared the factor structure of the PHQ-9 between different racial/ethnic groups as well as the rates of endorsement and differential item functioning (DIF) of the 9 items of the PHQ-9. The presence of DIF would indicate that responses to an individual item differ significantly between groups, controlling for the level of depression.
  
  
  METHODS
  A combined dataset from 2 separate studies of 5,053 primary care patients including non-Hispanic white (n=2,520), African American (n=598), Chinese American (n=941), and Latino (n=974) patients was used for our analysis. Exploratory principal components factor analysis was used to derive the factor structure of the PHQ-9 in each of the 4 racial/ethnic groups. A generalized Mantel-Haenszel statistic was used to test for DIF.
  
  
  RESULTS
  One main factor that included all PHQ-9 items was found in each racial/ethnic group with alpha coefficients ranging from 0.79 to 0.89. Although endorsement rates of individual items were generally similar among the 4 groups, evidence of DIF was found for some items.
  
  
  CONCLUSIONS
  Our analyses indicate that in African American, Chinese American, Latino, and non-Hispanic white patient groups the PHQ-9 measures a common concept of depression and can be effective for the detection and monitoring of depression in these diverse populations.
authors.affiliation: Department of Psychiatry, University of California, San Francisco, CA, USA. freddy@post.harvard.edu
authors.forename: Frederick Y
authors.initials: FY
authors.lastname: Huang
authors.forename: Henry
authors.initials: H
authors.lastname: Chung
authors.forename: Kurt
authors.initials: K
authors.lastname: Kroenke
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Delucchi
authors.forename: Robert L
authors.initials: RL
authors.lastname: Spitzer
mesh_terms: D000328:Adult; D003863:Depression / Q000175:diagnosis* / Q000453:epidemiology; D003866:Depressive Disorder / Q000175:diagnosis* / Q000453:epidemiology; D005006:Ethnicity; D005260:Female; D006801:Humans; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D044469:Racial Groups; D011795:Surveys and Questionnaires