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
Detailed write-up pending
A full, citation-backed scientific write-up for this scale — overview, clinical use, and psychometrics in the voice of a dissertation "Measures" section — has not yet been authored. To honor the platform's no-fabricated-sources rule, this page currently shows only the verified registry facts above (item count, structure, scoring, and any published norms). No validity coefficients, reliability figures, or citations are shown here that cannot be traced to a named source; the authored write-up will be added once its sources have been read and recorded in the plan-integrity file.
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.