title: Validation of the PHQ-9 in a psychiatric sample.
abstract: BACKGROUND
  The PHQ-9 was originally developed as a screener for depression in primary care and is commonly used in medical settings. However, surprisingly little is known about its psychometric properties and utility as a severity measure in psychiatric populations. We examined the full range of psychometric properties of the PHQ-9 in patients with a range of psychiatric disorders (i.e., mood, anxiety, personality, psychotic).
  
  
  METHODS
  Patients (n=1023) completed the PHQ-9 upon admission and discharge from a partial hospital, as well as other self-report measures of depression, anxiety, well-being, and a structured diagnostic interview.
  
  
  RESULTS
  Internal consistency was good (α=.87). The PHQ-9 demonstrated a strong correlation with a well-established measure of depression, moderate correlations with related constructs, a weak correlation with a theoretically unrelated construct (i.e., disgust sensitivity), and good sensitivity to change, with a large pre- to post-treatment effect size. Using a cut-off of ≥13, the PHQ-9 demonstrated good sensitivity (.83) and specificity (.72). A split-half exploratory factor analysis/confirmatory factor analysis suggested a two-factor solution with one factor capturing cognitive and affective symptoms and a second factor reflecting somatic symptoms. Psychometric properties did not differ between male and female participants.
  
  
  CONCLUSIONS
  No clinician-rated measure of improvement, and the sample lacked ethnoracial diversity.
  
  
  CONCLUSIONS
  This first comprehensive validation of the PHQ-9 in a large, psychiatric sample supported its use as a severity measure and as a measure of treatment outcome. It also performed well as a screener for a current depressive episode using a higher cut-off than previously recommended for primary care samples.
authors.affiliation: McLean Hospital/Harvard Medical School, United States. Electronic address: cbeard@mclean.harvard.edu.
authors.forename: C
authors.initials: C
authors.lastname: Beard
authors.affiliation: McLean Hospital/Harvard Medical School, United States.
authors.forename: K J
authors.initials: KJ
authors.lastname: Hsu
authors.affiliation: McLean Hospital/Harvard Medical School, United States.
authors.forename: L S
authors.initials: LS
authors.lastname: Rifkin
authors.affiliation: McLean Hospital/Harvard Medical School, United States.
authors.forename: A B
authors.initials: AB
authors.lastname: Busch
authors.affiliation: McLean Hospital/Harvard Medical School, United States.
authors.forename: T
authors.initials: T
authors.lastname: Björgvinsson
mesh_terms: D000328:Adult; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D001523:Mental Disorders / Q000175:diagnosis* / Q000523:psychology* / Q000628:therapy; D008875:Middle Aged; D011594:Psychometrics; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D055815:Young Adult
keywords: Assessment; Depression; PHQ-9; Psychometric; Validation