PHQ-9

How to use it

1. 1

   Covers last 2 weeks. Self-administered or clinician-administered.

2. 2

   Score ≥10 = probable major depression. Sensitivity ~88%, specificity ~88% for MDD.

3. 3

   Q9 critical. Any score > 0 on Q9 = immediate suicide risk assessment.

When to use it

Primary care depression screening

PHQ-9 widely adopted in GP/primary care annual reviews.

Treatment response monitoring

Score improvement ≥5 points = minimal clinically important difference.

Step-care decisions

PHQ-9 ≥10: initiate SSRI or structured psychological therapy (Step 3 NICE).