Patient Health Questionnaire-9
PHQ-9Permission: Free for research use. Free for non-commercial academic research, with no license fee. Cite the original publication.
A 9-item self-report instrument for screening and measuring the severity of depression, based on DSM diagnostic criteria.
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Reliability & validation
Scoring
- Total
- Sum of items 1–9
- Score range
- 0–27
- Reverse-keyed items
- None
- Mild
- 5–9
- Moderate
- 10–14
- Moderately severe
- 15–19
- Severe
- 20–27
Each item is scored 0 (not at all) to 3 (nearly every day).
Response anchors
Not at all · Several days · More than half the days · Nearly every day
Known limitations
Validated primarily in primary care settings. A score of 10 or more warrants clinical follow-up but does not constitute a diagnosis. Item 9 (suicidal ideation) requires clinical judgment independent of total score.
Original citation
Kroenke, K., Spitzer, R. L., & Williams, J. B. W. (2001). The PHQ-9: Validity of a brief depression severity measure. Journal of General Internal Medicine, 16(9), 606-613.
https://doi.org/10.1046/j.1525-1497.2001.016009606.xQuestions researchers ask
What does the PHQ-9 measure?
A 9-item self-report instrument for screening and measuring the severity of depression, based on DSM diagnostic criteria.
How many items does the PHQ-9 have?
The Patient Health Questionnaire-9 (PHQ-9) has 9 items.
Is the PHQ-9 free to use?
The PHQ-9 is free to use for non-commercial academic research. You don't need to pay a license fee, but you should always cite the original publication.
Is the PHQ-9 reliable?
Validation studies report Cronbach's α of 0.89, test–retest reliability of 0.84. See the reliability section for the population studied and full statistics.
Who developed the PHQ-9, and how do I cite it?
Kroenke, K., Spitzer, R. L., & Williams, J. B. W. (2001). The PHQ-9: Validity of a brief depression severity measure. Journal of General Internal Medicine, 16(9), 606-613. https://doi.org/10.1046/j.1525-1497.2001.016009606.x
How do you score the PHQ-9?
Total: Sum of items 1–9. Score range 0–27. Reverse-keyed items: None. Mild: 5–9. Moderate: 10–14. Moderately severe: 15–19. Severe: 20–27.
Related scales
Library entry verified September 2026. Metadata is provided for reference. Questionnaires are built in Folio Surveyor, subject to each instrument's licensing, and can be taken to Qualtrics, Google Forms or Microsoft Forms, with their CSV responses brought back for scoring.