About the PHQ-9
The Patient Health Questionnaire-9 was developed by Kroenke, Spitzer, and Williams (2001) and is licensed for free clinical use. It scores the 9 DSM criteria for major depressive disorder from 0 (not at all) to 3 (nearly every day), giving a maximum of 27 points. It's validated across primary care, hospital, and community settings, with the original validation study published in the Journal of General Internal Medicine.
Severity classification and treatment guidance
| Score | Severity | Suggested Action |
|---|---|---|
| 0-4 | None-minimal | Monitor. Watchful waiting. |
| 5-9 | Mild | Watchful waiting, repeat in 2-4 weeks. Consider guided self-help. |
| 10-14 | Moderate | Treatment plan. Consider counselling, CBT, and antidepressants. |
| 15-19 | Moderately severe | Active treatment with antidepressants and/or psychotherapy. Follow up closely. |
| 20-27 | Severe | Immediate initiation of pharmacotherapy. Referral to mental health specialist. |
Item 9 and suicide risk
Item 9 asks about thoughts of being better off dead or of hurting yourself. Any positive response requires direct clinical assessment. The PHQ-9 score itself doesn't predict suicide risk, it flags that a conversation must happen. Ask directly, assess lethality, and document your assessment.
PHQ-2 as an initial screen
The PHQ-2 uses only items 1 and 2 (anhedonia and depressed mood). A score of 3 or above on the PHQ-2 warrants full PHQ-9 assessment. Sensitivity 83%, specificity 92% for major depression at this cutoff.
Related tools
For anxiety screening, see GAD-7 Anxiety Scale. For occupational burnout, see Burnout Index. For sleep quality assessment, see Sleep Quality Score. For overall stress measurement, see Perceived Stress Scale. Depression and metabolic health are closely linked, patients with depression have elevated cardiovascular risk, so consider assessing 10-year cardiovascular risk with the Framingham Risk Score alongside mental health screening.
References
- Kroenke K, Spitzer RL, Williams JBW. "The PHQ-9: validity of a brief depression severity measure." J Gen Intern Med. 2001;16(9):606-613.
- NICE Guideline CG90. Depression in adults: recognition and management. NICE, 2009 (updated 2022).