Background: Experiencing natural disasters is associated with common mental disorders including major depressive disorder (MDD). However, the latent structure of MDD is widely debated, and few studies examined the structure of MDD in Chinese natural disaster survivors. Therefore, this study aimed to evaluate the factorial validity of the Patient Health Questionnaire-9 (PHQ-9) for DSM-5 major depressive disorder (MDD) symptoms in Chinese earthquake survivors.
Method: Participants were 1058 Chinese earthquake survivors. Self-reported measures included the PHQ-9 and the Short-Form Health Survey (SF-36). Confirmatory factor analysis (CFA) and structural equation modelling (SEM) was used to examine the latent structure of MDD and the associations between latent factors of MDD and different aspects of health-related quality of life, respectively.
Results: The model comprised of somatic and non-somatic factors demonstrated significantly better fit than the other competing MDD models in the current sample. Further structural equation modeling analyses indicated that the non-somatic factor was significantly associated with both physical and psychosocial health-related quality of life, while the somatic factor was a uniquely predictor of physical health-related quality of life. Furthermore, the somatic factor was found to partially mediate the relationship between the non-somatic factor and physical health-related quality of life.
Conclusions: The MDD symptoms was best captured by a two-factor model comprised of somatic and non-somatic factors in Chinese natural disaster survivors. The two MDD factors were differentially associated with physical and psychosocial health-related quality of life, and the non-somatic factor associated physical health-related quality of life partially through the somatic factor. The current findings add to extant knowledge of latent structure of MDD symptoms, and carry implications for assessment and intervention of post-disaster mental health problems.