The PHQ-9 is the 9-item depression module from the full The Patient Health Questionnaire (PHQ which is designed to be entirely self-administered by a patient.
Over the past 2 weeks, how often have you been bothered by any of the following problems?
- K Kroenke, RL Spitzer, JB Williams. The PHQ-9: Validity Of A Brief Depression Severity Measure. 16(9): J Gen Intern Med 606-13.