andhines/phq-9-questionnaire

PHQ-9 Questionnaire

The PHQ-9 was developed by Dr. Robert L. Spitzer, Dr. Janet B.W. Williams, and their colleagues as part of the PRIME-MD diagnostic tool, which was funded by Pfizer Inc. It is based on the diagnostic criteria for major depressive disorder in the DSM-IV and has been widely validated in numerous studies. The tool's reliability and validity have been established across various settings and populations, making it one of the most trusted and widely used depression screening instruments in clinical practice. Its simplicity, brevity, and strong psychometric properties contribute to its broad acceptance and utility in both clinical and research settings.