Patient Health Questionnaire–9 (PHQ-9)
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The PHQ-9 is a self-report questionnaire used to screen for symptoms of depression and assess severity. It is widely used in primary care, behavioral health, and clinical research to support early identification and ongoing symptom monitoring.
Recommended Frequency: Every 2–4 weeks during active treatment, or as clinically indicated for ongoing monitoring.
About the PHQ-9
The PHQ-9 is a 9-item depression screener based on the diagnostic criteria for major depressive disorder in the DSM. It is brief, easy to score, and designed for use in primary care and mental health settings. It assesses both the presence and frequency of depressive symptoms over the past two weeks, making it useful for both initial screening and tracking treatment response.
Psychometric Properties
The PHQ-9 demonstrates excellent internal consistency (α = 0.86–0.89) and strong diagnostic validity. It has been validated in thousands of patients across primary care and psychiatric populations. A cutoff score of 10 or above is often used as a threshold for clinically significant depressive symptoms, with a sensitivity of 88% and specificity of 88% for major depressive disorder.
Source: Kroenke et al., 2001
The Scale
Each item corresponds to a core DSM symptom of depression. Respondents rate how often they’ve experienced each symptom over the past two weeks using a 4-point scale:
- “Not at all” (0)
- “Several days” (1)
- “More than half the days” (2)
- “Nearly every day” (3)
An additional 10th item asks about the impact of these symptoms on daily functioning, though it is not scored as part of the total.
Score Range
Total scores range from 0 to 27. Interpretation guidelines:
- 0–4: Minimal depression
- 5–9: Mild
- 10–14: Moderate
- 15–19: Moderately severe
- 20–27: Severe
Higher scores indicate greater severity and may warrant further clinical evaluation or treatment planning.
Copyright
© Pfizer Inc. The PHQ-9 is part of the PRIME-MD screening tools developed by Drs. Spitzer, Kroenke, and Williams.
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. https://doi.org/10.1046/j.1525-1497.2001.016009606.x
- Kroenke, K., & Spitzer, R. L. (2002). The PHQ-9: A new depression diagnostic and severity measure. Psychiatric Annals, 32(9), 509–515. https://www.healio.com/news/psychiatry/20210318/the-phq9-a-new-depression-diagnostic-and-severity-measure
Disclaimer
This content is provided for informational purposes only and is not a substitute for clinical judgment. HiBoop does not provide diagnostic services or interpret assessment scores.
Permissions
The PHQ-9 is freely available for use in clinical practice, education, and research without permission or license, as long as it is not modified or sold. See Pfizer Press Release
Frequently Asked Questions
Can this be completed remotely?
Yes. HiBoop supports secure digital administration with automatic scoring and clinician alerts.
How often should the PHQ-9 be used?
Every 2 weeks is standard in active treatment, or at each session in brief therapy settings.
What does a non-zero score on question 9 mean?
Any answer other than “Not at all” to item 9 (suicidal thoughts) should prompt follow-up questions and, if needed, a risk assessment.
Can the PHQ-9 be used with teens?
Yes. It is validated for use in adolescents 12 and up.
Is the PHQ-9 a diagnostic tool?
No. It supports diagnosis but should always be used alongside a full clinical assessment.