Are comparisons of mental disorders between Chinese and German students possible? An examination of measurement invariance for the PHQ-15, PHQ-9 and GAD-7

BACKGROUND: The Patient Health Questionnaire (PHQ) is one of the most commonly used instruments to assess mental disorders. However, research on its cross-cultural measurement invariance is not yet sufficient. This study examined the measurement invariance of the Chinese and German versions of the PHQ’s somatic symptom severity scale (PHQ-15), depressive symptom severity scale (PHQ-9) and seven-item Generalized Anxiety Disorder (GAD-7) scale as a prerequisite for their use in cross-cultural comparisons. METHODS: We used online data collected from groups of Chinese students in China (n = 413) and German students in Germany (n = 416). Separate measurement models for each group were examined using confirmatory factor analysis and measurement invariance testing was conducted to test the cross-cultural equivalence. RESULTS: Findings demonstrated that the PHQ-9 and GAD-7 had partial scalar measurement invariance, but the cross-cultural measurement invariance of the PHQ-15 could not be confirmed. Comparisons of latent means did not indicate differences in the levels of depression and anxiety symptoms between Chinese and German samples. CONCLUSION: The PHQ-9 and GAD-7 can be used in cross-cultural comparison of prevalence, but the intercultural use of PHQ-15 is more problematic. Findings are discussed from intercultural and methodological perspectives.