PHQ-9 Scoring Guide for Depression Assessment
The PHQ-9 is a validated depression screening tool with scores categorized as: 5-9 for mild depression, 10-14 for moderate depression, 15-19 for moderately severe depression, and ≥20 for severe depression, with specific interventions recommended for each severity level. 1
PHQ-9 Scoring Categories and Recommended Interventions
| PHQ-9 Score | Severity Category | Recommended Intervention |
|---|---|---|
| 1-7 | None/Mild | No intervention required; patient likely has effective coping skills |
| 8-14 | Moderate | Seek consultation with psychology/psychiatry; consider low-intensity interventions |
| 15-19 | Moderately Severe | Referral to psychology/psychiatry for diagnosis and treatment |
| 20-27 | Severe | Urgent referral for psychiatric evaluation |
Administration Protocol
The PHQ-9 should be administered at key clinical touchpoints:
- Initial diagnosis
- Regular intervals during treatment
- 3,6, and 12 months after treatment
- At diagnosis of recurrence or progression
- During times of personal transition or reappraisal 1
Screening Process
Initial Screening with PHQ-2
Many clinicians begin with the PHQ-2, which consists of the first two items of the PHQ-9:
- Little interest or pleasure in doing things (anhedonia)
- Feeling down, depressed, or hopeless (depressed mood)
If the patient scores 2 or higher on the PHQ-2 (out of a possible 6 points), proceed with the full PHQ-9 assessment 2, 3.
Full PHQ-9 Assessment
The PHQ-9 scores each of the 9 DSM criteria for depression on a scale from "0" (not at all) to "3" (nearly every day) over the past two weeks 4. Total scores range from 0-27.
Clinical Significance and Interpretation
- A PHQ-9 score ≥10 has a sensitivity of 88% and specificity of 88% for major depression 4
- Target treatment goal: 50% reduction in PHQ-9 score or achievement of score <5 (remission) 1
- Minimal clinically important difference for individual change is 5 points on the 0-27 point scale 5
Important Considerations
Self-Harm Assessment
Item 9 of the PHQ-9 assesses thoughts of self-harm ("Thoughts that you would be better off dead or hurting yourself in some way"). This item is critical for safety assessment:
- If the patient endorses any frequency of self-harm thoughts, conduct an immediate risk assessment
- If at risk of harm to self and/or others, provide emergency evaluation by a licensed mental health professional 2, 1
Common Pitfalls to Avoid
- Omitting the self-harm question (item 9): This artificially lowers the score and may miss critical safety concerns 2, 1
- Inconsistent follow-up: Regular monitoring is essential for tracking treatment response
- Relying solely on total score: Pay attention to individual item responses, especially item 9 on self-harm
- Relying solely on clinical impression: The PHQ-9 provides objective measurement of depression severity 1
Algorithm Scoring vs. Summed-Item Scoring
Research indicates that the summed-item score method (using the total PHQ-9 score with a cutoff of ≥10) has better diagnostic performance than the algorithm scoring method (which follows DSM criteria patterns) for screening purposes 6. For clinical practice, the summed-item scoring approach is recommended for its superior sensitivity.
Psychometric Properties
- Internal consistency: 0.82
- Test-retest reliability over a 2-week interval: 0.76 7
- The PHQ-9 has demonstrated excellent responsiveness to treatment, making it valuable for monitoring outcomes 5
The PHQ-9's brevity, strong psychometric properties, and alignment with DSM criteria make it an ideal tool for both initial assessment and ongoing monitoring of depression in clinical settings.