Patient Health Questionnaire-9 (PHQ-9)
A depressive-symptom severity and screening measure requiring clinical context.
Questionnaire The format describes how observations are obtained, not an evidence rating.
What it measures
Reported DSM-aligned depressive symptoms over the past 2 weeks, with a total score used in severity and screening research.
What people do
The nine-item module asks how often each problem has bothered the respondent over the past 2 weeks, rated from 0 (Not at all) to 3 (Nearly every day), followed by a non-scored question on functional difficulty. Item 9 asks about thoughts of being better off dead or of hurting oneself, so formal use requires a setting prepared to evaluate and respond to positive endorsements.
What the scores mean
Each of the nine items contributes 0–3 to a 0–27 total; in the 2001 validation study, cut points of 5, 10, 15 and 20 marked mild, moderate, moderately severe and severe symptom bands. A screening threshold is a decision rule, not proof of a diagnosis or the cause of symptoms.
This explains the logic of a score. It does not supply a test form, individual result or administration manual.
Development and versions
Kurt Kroenke, Robert Spitzer and Janet Williams evaluated the PHQ-9 in the 2001 validation article within the broader Primary Care Evaluation of Mental Disorders (PRIME-MD) and PHQ lineage.
Evidence: (Kroenke et al., 2001); (Spielman et al., 2020)
Reliability and validity evidence
In 580 independent interviews drawn from the original study, the threshold of 10 had 88% sensitivity and 88% specificity for major depression. These figures are tied to that study and criterion, not every population.
Evidence belongs to a version, sample and interpretation. Read the source notes for what was actually inspected.
Evidence: (Kroenke et al., 2001); (Spielman et al., 2020)
Where it is used
Clinical and research symptom tracking or screening with appropriate follow-up. This site does not administer the questionnaire.
Limits and common misreadings
- Screening positives include false positives.
- Identical totals can conceal different symptom patterns.
- Clinical assessment must consider impairment, history and alternative explanations.
Read an example
Original teaching example
An original synthetic example in the score lab holds sensitivity and specificity constant while changing prevalence. The fraction of positive screens representing cases changes, even though the threshold has not. No visitor’s symptoms are scored.
Constructed for learning; this is not a result from the instrument’s validation study.
Access and permission
Pfizer made the standard PHQ-9 forms publicly available without fee for research and clinical use (see phqscreeners.com); always use an unaltered official form and verify terms for software or commercial adaptations.
Textbook connection
Related contextPsychology 2e: 15.1 What Are Psychological Disorders?
Conceptual context; the instrument-specific sources in this profile provide the primary evidence.
Related measures
Read a measure critically · Explore score examples · Review research methods
Sources and inspection notes
Checked October 22, 2026. An inspection date is not a publication date. Publisher information is not presented as independent validation; abstract-only and indexed-excerpt access are identified below.
- Kroenke, K., Spitzer, R. L., & Williams, J. B. (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.xConsulted sourcePrimary research: indexed abstract
6,000 respondents and 580 independent interviews; 0–27 severity bands (5, 10, 15, 20) and the sensitivity and specificity quoted here belong to that study, criterion and cutoff.
- Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2020). Psychology 2e. OpenStax. https://openstax.org/books/psychology-2e/pages/15-1-what-are-psychological-disordersTextbook: conceptual context
Conceptual context; the instrument-specific sources in this profile provide the primary evidence.