Validation of the nine-item Patient Health Questionnaire to screen for major depression in a Chinese primary care population.

Introduction The aim of this study was to examine the reliability and validity of the nine-item Patient Health Questionnaire (PHQ-9) for screening depression in Chinese primary care settings. Methods In 100 randomly selected primary care clinics (PCC) of Hangzhou city, we recruited 2,639 patients (aged ≥18 years) and applied the PHQ-9 to screen for depression. Then, 280 of them were further interviewed with the Structured Clinical Interview for Diagnostic and Statistical Manual Disorders (SCID) for the diagnosis of major depression. Statistical analysis of the demographic data, reliability, validity and receiver–operator curve were performed. Results The mean administration time was 7 minutes, and the Cronbach's α was 0.89. The optimal cutoff score of 10 on the PHQ-9 revealed a sensitivity of 0.87, specificity of 0.81, and positive likelihood ratio of 5.04. The area under the receiver–operator curve in this study was 0.91 (95% confidence interval, 0.87–0.94). Discussion The PHQ-9 performs well and has acceptable psychometric properties for screening of patients with depression in a Chinese primary care population.