Instrument reference
Patient Health Questionnaire-9 (PHQ-9)
Free · no permission required (developer statement) Licence statement checked
- Construct measured
- Depressive symptom severity over the past two weeks, mapped to DSM-IV depressive-episode criteria in its original form.
- Category
- Depression and anxiety screening
- Intended population
- Adults, originally validated in primary-care settings; adolescent adaptations exist and are separate instruments.
- Number of items
- 9 symptom items plus a functional-difficulty question (per the developer's form).
- Administration format
- Self-report questionnaire; brief, typically a few minutes.
- Scoring approach
- Item ratings are summed into a severity score using the developer's published instructions. This catalogue does not reproduce items or scoring tables.
- Language and population validation
- Many official translations are listed on the developer site. Validation in specific Indian languages and populations must be checked in the literature before use.
Reliability and validity evidence
- Original validation in US primary-care and obstetrics–gynaecology patients reported good criterion validity against structured interviews. — Kroenke et al. (2001)
- Widely used in research worldwide; performance varies by population, language and cut-off, so local validation evidence should be consulted. — Kroenke et al. (2001)
Interpretation cautions
- Screens for, but does not diagnose, depression.
- Includes an item about thoughts of death or self-harm; any positive response requires prompt, appropriate human follow-up under a local safety protocol.
- Somatic items may be elevated by physical illness.
Copyright and licence
Free · no permission required (developer statement)
The developer distribution site states that the PHQ and GAD-7 screeners and translations may be downloaded and that no permission is required to reproduce, translate, display or distribute them (statement as quoted in CamCOPS documentation).
The developer states that no permission is needed to reproduce, translate, display or distribute. Attribution is still good practice.
Official source
PHQ Screeners (developer site) (opens in a new tab)
Rights and evidence last verified: 2026-10-19.