How to Score the PHQ-9 and GAD-7
Both the PHQ-9 and GAD-7 are scored by summing the individual item responses, where each of the 9 (PHQ-9) or 7 (GAD-7) items is rated from 0 to 3, yielding total scores of 0-27 and 0-21 respectively. 1
PHQ-9 Scoring Method
Item Rating Scale:
- Each of the 9 items asks how often the patient has been bothered by specific problems over the past two weeks 1
- Response options are scored as: 0 = "not at all," 1 = "several days," 2 = "more than half the days," 3 = "nearly every day" 1
Total Score Calculation:
- Add all 9 item scores together to get a total ranging from 0 to 27 1
Score Interpretation:
- The standard cutoff is ≥10 for detecting major depressive disorder, though some populations may benefit from lower thresholds 2, 3
- In a Peruvian hospital study, a cutoff of ≥7 showed optimal sensitivity and specificity 4
- Scores can be categorized as: minimal (0-4), mild (5-9), moderate (10-14), moderately severe (15-19), and severe (20-27) depression 2
GAD-7 Scoring Method
Item Rating Scale:
- Each of the 7 items asks how often the patient has been bothered by anxiety problems over the past two weeks 1
- Response options use the identical 0-3 scale: 0 = "not at all," 1 = "several days," 2 = "more than half the days," 3 = "nearly every day" 1
Total Score Calculation:
- Sum all 7 item scores for a total ranging from 0 to 21 1
Score Interpretation:
- Scores of ≥5,10, and 15 represent mild, moderate, and severe anxiety levels respectively 1
- The optimal screening cutoff is ≥10 for detecting generalized anxiety disorder 2
- Alternative cutoffs include ≥8 (higher sensitivity) or ≥9 (better balance of sensitivity and specificity) 5, 3
- Score ranges: 0-4 (minimal anxiety), 5-9 (mild anxiety), 10-14 (moderate anxiety), 15-21 (severe anxiety) 1
Critical Clinical Actions Based on Scores
Immediate Risk Assessment:
- Any positive response to PHQ-9 item 9 (thoughts of self-harm) requires immediate evaluation for suicide risk, regardless of total score 1
- Patients identified as at risk of harm to self or others require emergency psychiatric referral 1
Moderate to Severe Scores (PHQ-9 ≥10 or GAD-7 ≥10):
- Conduct further diagnostic assessment to identify the nature and extent of symptoms and presence of mood or anxiety disorders 1
- Evaluate for medical or substance-induced causes of symptoms 1
- Consider referral to psychiatry, psychology, or equivalently trained mental health professional 1
Functional Impairment Question:
- Both scales include a final question about functional difficulty that is not scored but provides important clinical context about symptom impact 1
Common Pitfalls
Cross-Cultural Considerations:
- Optimal cutoff scores may vary across populations and settings 4
- The PHQ-9 and GAD-7 have lower specificity in some low- and middle-income countries compared to high-income settings 4
- Both scales may have high false positive rates in certain populations, making them better suited as initial screening tools rather than definitive diagnostic instruments 3
Somatic Symptoms: