The PHQ-9 (original) (raw)

Abstract

OBJECTIVE: While considerable attention has focused on improving the detection of depression, assessment of severity is also important in guiding treatment decisions. Therefore, we examined the validity of a brief, new measure of depression severity.

MEASUREMENTS: The Patient Health Questionnaire (PHQ) is a self-administered version of the PRIME-MD diagnostic instrument for common mental disorders. The PHQ-9 is the depression module, which scores each of the 9 DSM-IV criteria as “0” (not at all) to “3” (nearly every day). The PHQ-9 was completed by 6,000 patients in 8 primary care clinics and 7 obstetrics-gynecology clinics. Construct validity was assessed using the 20-item Short-Form General Health Survey, self-reported sick days and clinic visits, and symptom-related difficulty. Criterion validity was assessed against an independent structured mental health professional (MHP) interview in a sample of 580 patients.

RESULTS: As PHQ-9 depression severity increased, there was a substantial decrease in functional status on all 6 SF-20 subscales. Also, symptom-related difficulty, sick days, and health care utilization increased. Using the MHP reinterview as the criterion standard, a PHQ-9 score ≥10 had a sensitivity of 88% and a specificity of 88% for major depression. PHQ-9 scores of 5, 10, 15, and 20 represented mild, moderate, moderately severe, and severe depression, respectively. Results were similar in the primary care and obstetrics-gynecology samples.

CONCLUSION: In addition to making criteria-based diagnoses of depressive disorders, the PHQ-9 is also a reliable and valid measure of depression severity. These characteristics plus its brevity make the PHQ-9 a useful clinical and research tool.

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Authors and Affiliations

  1. the Regenstrief Institute for Health Care and Department of Medicine, Indiana University, Indianapolis, Ind
    Kurt Kroenke MD
  2. the New York State Psychiatric Institute and Department of Psychiatry, Columbia University, New York, NY
    Robert L. Spitzer MD & Janet B. W. Williams DSW

Authors

  1. Kurt Kroenke MD
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  2. Robert L. Spitzer MD
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  3. Janet B. W. Williams DSW
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Corresponding author

Correspondence to Kurt Kroenke MD.

Additional information

The development of the PHQ-9 was underwritten by an educational grant from Pfizer US Pharmaceuticals, New York, NY. PRIME-MD is a trademark of Pfizer Copyright held by Pfizer.

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Kroenke, K., Spitzer, R.L. & Williams, J.B.W. The PHQ-9.J GEN INTERN MED 16, 606–613 (2001). https://doi.org/10.1046/j.1525-1497.2001.016009606.x

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