Patient Health Questionnaire-9
Screen for and monitor the severity of depressive symptoms, mapped directly onto diagnostic criteria.
Complete it
Over the last 2 weeks, how often have you been bothered by any of the following problems?
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
Poor appetite or overeating
Feeling bad about yourself — or that you are a failure or have let yourself or your family down
Trouble concentrating on things, such as reading the newspaper or watching television
Moving or speaking so slowly that other people could have noticed — or the opposite, being so fidgety or restless that you have been moving around a lot more than usual
Thoughts that you would be better off dead, or of hurting yourself in some way
No treatment indicated on this measure alone.
Psychometrics
The PHQ-9 is the most widely used depression measure in general practice and in stepped-care systems worldwide. It has been validated across dozens of languages and settings, with internal consistency typically α ≈ 0.86–0.89 and good test–retest reliability.
At the conventional cut-point of 10, pooled sensitivity and specificity are both roughly 0.85 for major depression in general population and primary care samples, though estimates vary considerably by setting and by whether the reference standard was a structured or semi-structured interview.
Cautions and misuse
What a score is not
A PHQ-9 score is not a diagnosis. Somatic items — sleep, appetite, energy, concentration — are elevated by medical illness, pain, pregnancy, shift work and medication side effects, so the instrument over-identifies depression in medically ill populations. Confirm with interview.
Cut-points derived in one population do not transport automatically to another. Measurement invariance across language and cultural groups is imperfect, and somatic versus affective item endorsement varies systematically by culture.
Sources
Kroenke, K., Spitzer, R. L., & Williams, J. B. W. (2001). The PHQ-9: Validity of a brief depression severity measure. Journal of General Internal Medicine, 16(9), 606–613
measureLevis, B., Benedetti, A., & Thombs, B. D. (2019). Accuracy of the PHQ-9 for screening to detect major depression: Individual participant data meta-analysis. BMJ, 365, l1476
meta-analysis