title: Comparing the Beck Depression Inventory-II (BDI-II) and Patient Health Questionnaire (PHQ-9) depression measures in an integrated mood disorders practice.
abstract: BACKGROUND
  Patient self-assessment instruments are useful in screening, tracking, and documenting the course of depressive symptoms with minimal clinician time. Two popular instruments are the Beck Depression Inventory (BDI-II) and the Patient Health Questionnaire (PHQ-9). We compared the performance of these two instruments in a mood disorders setting.
  
  
  METHODS
  A retrospective study of 625 patients who completed a PHQ-9 and BDI-II as part of routine clinical care (1) during initial outpatient evaluation between 2008 and 2009, and (2) on admission to an inpatient mood disorders unit between 2006 and 2009. Pearson correlation coefficients for total PHQ-9 and BDI-II scores were calculated for all patients, the outpatients, and the inpatients.
  
  
  RESULTS
  Overall r=0.77, indicating strong correlation, more in the outpatients (n=287, r=0.81) than the inpatients (n=338, r=0.67). Mean PHQ-9 and BDI-II scores for the outpatients were 15.1 (SD 7.4) and 27.8 (SD 14.1) corresponding to "moderately severe" and "moderate" categories respectively; for inpatients, 18.9 (SD 5.7) and 33.8 (SD 11.5) corresponding to "moderately severe" and "severe."
  
  
  CONCLUSIONS
  Retrospective design and no monitoring of which instrument was completed first in case that influenced patient response to the second instrument
  
  
  CONCLUSIONS
  PHQ-9 and BDI-II scores, as continuous but not categorical variables, in a mood disorders subspeciality setting are closely correlated and essentially interchangeable. There are practical applications to our findings, as the PHQ-9 is shorter and free.
authors.affiliation: Mayo Clinic Department of Psychiatry and Psychology, 200 First Street SW, Rochester, MN 55905, USA. kung.simon@mayo.edu
authors.forename: Simon
authors.initials: S
authors.lastname: Kung
authors.forename: Renato D
authors.initials: RD
authors.lastname: Alarcon
authors.forename: Mark D
authors.initials: MD
authors.lastname: Williams
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Poppe
authors.forename: Mary
authors.initials: M
authors.lastname: Jo Moore
authors.forename: Mark A
authors.initials: MA
authors.lastname: Frye
mesh_terms: D019033:Delivery of Health Care, Integrated; D003863:Depression / Q000175:diagnosis*; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008605:Mental Health Services / Q000458:organization & administration; D011569:Psychiatric Status Rating Scales; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires