Longitudinal measurement invariance and psychometric properties of the Patient Health Questionnaire-Four in China

Depression and anxiety symptoms among medical students are often a concern. The Patient Health Questionnaire-Four (PHQ-4), an important tool for depression and anxiety screening, is commonly used and easy to administer. This study aimed to assess and update the longitudinal measurement invariance and psychometric properties of the simplified Chinese version. A three-wave longitudinal survey was conducted among healthcare students using the PHQ-4. Structural validity was based on one-factor, two-factor, and second-order factor models, construct validity was based on the Self-Rated Health Questionnaire (SRHQ), Sleep Quality Questionnaire (SQQ), and Rosenberg Self-Esteem Scale (RSES), and longitudinal measurement invariance (LMI), internal consistency, and test–retest reliability were based on structural consistency across three time points. The results of the confirmatory factor analysis indicated that two-factor model was the best fit, and LMI was supported at three time points. Inter-factor, factor-total, and construct validity correlations of the PHQ-4 were acceptable. Additionally, Cronbach’s alpha, McDonald’s omega, and the intraclass correlation coefficient demonstrated acceptable/moderate to excellent reliability of the PHQ-4. This study adds new longitudinal evidence that the Chinese version of the PHQ-4 has promising LMI and psychometric properties. Such data lends confidence to the routine and the expanded use of the PHQ-4 for routine screening of depression and anxiety in Chinese healthcare students.