Patient Health Questionnaire-9
A 9-item self-report screener for the severity of depressive symptoms over the past two weeks. Public-domain instrument intended for use under clinician supervision.
This is a clinical instrument. It is not publicly self-administered — a clinician assigns it through a secure patient link.
At a glance
What it measures
The Patient Health Questionnaire-9 (Kroenke, Spitzer, & Williams, 2001) is a 9-item self-report screener for the severity of depressive symptoms over the past two weeks. Each item asks how often a symptom has bothered the respondent, scored 0–3, and the summed total is compared with the published severity bands shown in the scoring section of this page.
It is a public-domain instrument that requires no permission to reproduce, which is why it has become one of the most widely deployed depression screeners in primary care. A positive screen is an indication for clinical follow-up, not a diagnosis.
Psychometric properties
The notes below are reproduced from the platform's psychometrics register for this instrument — the same source-cited reliability, validity, and norms text that accompanies its downloadable report.
Excellent internal consistency (Cronbach's alpha 0.86-0.89) and good test-retest reliability (Kroenke, Spitzer & Williams, 2001).
At a cutoff of 10, sensitivity and specificity for major depression are both about 0.88 (Kroenke et al., 2001).
Validated in large primary-care and obstetric-gynecologic samples; severity bands at totals of 5, 10, 15, and 20.
Example item
“Little interest or pleasure in doing things”
Illustrative only. During administration items are presented one screen-set at a time; response-key direction is never shown to respondents.
Scoring & interpretation
Item responses are summed to a total score and compared against published screening cutoffs.
| Band | Threshold | Interpretation |
|---|---|---|
| Minimal | ≥ 0 | Total 0–4: minimal or no depressive symptoms. |
| Mild | ≥ 5 | Total 5–9: mild depressive symptoms; consider watchful waiting and repeat assessment. |
| Moderate | ≥ 10 | Total 10–14: moderate depression; a treatment plan should be considered. |
| Moderately severe | ≥ 15 | Total 15–19: moderately severe depression; active treatment is warranted. |
| Severe | ≥ 20 | Total 20–27: severe depression; immediate treatment and close follow-up are warranted. |
Psychometrics & norms
| Scale | M | SD | N | α | Metric |
|---|---|---|---|---|---|
| Depression Severity | — | — | 2519 | — | empirical percentile table |
Kliem et al. (2024), Frontiers in Psychiatry, 15:1483782 (open access, CC BY) — cumulative population percentiles for the summed PHQ-9 (9 items, 0–3, total 0–27) in a German general-population reference sample (N = 2,519; Cronbach’s α = 0.90). Higher percentiles indicate more frequent depressive symptoms. The source does not publish a scale-level standard deviation, so no confidence range is shown. General-population norms are country-dependent; this is a German reference sample.
Source & 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. Public domain (no permission required).
Scoring. Severity bands per 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 (0–4 minimal, 5–9 mild, 10–14 moderate, 15–19 moderately severe, 20–27 severe). Item 9 (self-harm) is reviewed individually regardless of total.
PHQ-9 © Pfizer Inc. Developed by Drs. Robert L. Spitzer, Janet B. W. Williams, Kurt Kroenke and colleagues. No permission is required to reproduce, translate, display, or distribute it.
References
- 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.
- Kroenke, K., & Spitzer, R. L. (2002). The PHQ-9: a new depression diagnostic and severity measure. Psychiatric Annals, 32(9), 509-515.