Patient Health Questionnaire – 9
PHQ-9Depression Screening (DSM-aligned)
9 items
2001
α 0.86–0.89
Free
Kroenke, K. & Spitzer, R.L.
Clinical safeguarding note: Freely available — public domain. Item 9 screens for suicidal ideation; follow clinical protocols. Paired with GAD-7 as a standard mental health battery. Often primary outcome in depression RCTs.
What it measures
A brief, freely available screening tool for major depression aligned to DSM-IV criteria. Each item corresponds to one diagnostic criterion. Cut-off >=10 indicates clinically significant depression. Widely used in primary care and clinical trials.
Representative items
- Little interest or pleasure in doing things
- Feeling down, depressed, or hopeless
- Trouble falling or staying asleep, or sleeping too much
- Feeling tired or having little energy
Citation
Kroenke, K., & Spitzer, R.L. (2002). The PHQ-9: A new depression diagnostic and severity measure. Psychiatric Annals, 32(9), 509–515.