title: Screening for major depressive disorder with the Patient Health Questionnaire (PHQ-9 and PHQ-2) in an outpatient clinic staffed by primary care physicians in Japan: a case control study.
abstract: OBJECTIVE
  The Patient Health Questionnaire (PHQ-9) is a self-report questionnaire commonly used to screen for depression, with ≥8-11 generally recommended as the cut-off. In Japan, studies of the validity of the PHQ-9 and PHQ-2 have been limited. In this study, we examined the utility of the PHQ-9 and PHQ-2 at an outpatient clinic in a Medical University Hospital in Japan.
  
  
  METHODS
  New consecutive outpatients were included in the study. We administered the PHQ-9 to 574 patients, and acquired complete PHQ-9 and PHQ-2 data for 521 patients. Major depressive disorders were diagnosed according to the DSM-IV-TR.
  
  
  RESULTS
  Forty-two patients were diagnosed with major depressive disorders. The mean PHQ-9 (15.7) and PHQ-2 (3.8) scores of the patients with major depressive disorders were significantly higher than the scores of the patients without depression (6.0 (PHQ-9) and 1.8 (PHQ-2)). The best cut-off points for the PHQ-9 and PHQ-2 summary scores were ≥11 (sensitivity 0.76, specificity 0.81) and ≥3 (sensitivity 0.76, specificity 0.82), respectively. No relationship was observed between the age and PHQ-9 scores.
  
  
  CONCLUSIONS
  The PHQ-9 and PHQ-2 were useful instruments for screening for major depressive disorders. The best cut-off point for the PHQ-9 summary score should be ≥11 to detect depression in the primary care setting in Japan.
authors: Department of General Medicine, Asahikawa University Hospital, Asahikawa, Hokkaido, Japan; Department of General Internal Medicine, Asahikawa City Hospital, Asahikawa, Hokkaido, Japan.
authors: Keiko
authors: K
authors: Suzuki
authors: Department of General Medicine, Asahikawa University Hospital, Asahikawa, Hokkaido, Japan.
authors: Shima
authors: S
authors: Kumei
authors: Department of General Medicine, Asahikawa University Hospital, Asahikawa, Hokkaido, Japan.
authors: Masumi
authors: M
authors: Ohhira
authors: Department of Regional Medicine and Education, Asahikawa University Hospital, Asahikawa, Hokkaido, Japan.
authors: Tsukasa
authors: T
authors: Nozu
authors: Department of General Medicine, Asahikawa University Hospital, Asahikawa, Hokkaido, Japan.
authors: Toshikatsu
authors: T
authors: Okumura
mesh_terms: D000367:Age Factors; D000554:Ambulatory Care Facilities; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000175:diagnosis*; D006262:Health; D006801:Humans; D007564:Japan; D008403:Mass Screening; D008875:Middle Aged; D058007:Physicians, Primary Care; D012372:ROC Curve; D011795:Surveys and Questionnaires