Psychometric properties of Mongolian versions of the PHQ-9 and GAD-7 in young adults

The Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) are standardized self-report tools for screening depressive and anxiety disorders, respectively. While they have been validated in various cultural contexts, their psychometric properties have not been thoroughly evaluated in Mongolia. This study aimed to validate the PHQ-9 and GAD-7 among young adults in Mongolia, ensuring their reliability and efficacy in assessing mental health. A cross-sectional study was conducted with 1,391 young adults (aged 17-29 years). Tests for internal consistency, test-retest reliability, and validity were performed, including exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). Convergent validity and cut-off scores were assessed using the Hospital Anxiety and Depression Scale (HADS). Results: Both the PHQ-9 and GAD-7 demonstrated excellent internal consistency (Cronbach’s alpha=0.913 and 0.895, respectively) and good test-retest reliability over time (ICC=0.637 for PHQ-9; ICC=0.782 for GAD-7). Factor analyses confirmed their unidimensional structures, explaining 59.1% and 61.5% of variance, respectively. Unidimensional models showed acceptable goodness-of-fit indices, with RMSEA values of 0.051 for PHQ-9 and 0.047 for GAD-7, indicating a close-to-good fit for both models. Strong correlations were observed between PHQ-9 and GAD-7 scores with HADS scores (p