Accommodating flourishing and depressive symptoms into the bifactor (S-1) model of mental health: longitudinal invariance and criterion validity.

This study examined the longitudinal reliability and validity of the bifactor (S-1) model of mental health among 371 Chinese university students, refining the dual-factor model that views mental health as encompassing both flourishing and psychopathology. Using depression as the reference factor, participants completed measures of depressive symptoms (CES-D), flourishing (MHC-SF), and well-being (PERMA Profiler) at two time points. Factor analyses showed that the bifactor (S-1) model achieved excellent fit and interpretability, outperforming the symmetrical bifactor model by yielding fewer anomalous loadings and clearer separation of general and specific factors. Structural equation modeling further demonstrated that both the general reference factor and the flourishing-specific factor at baseline independently predicted multiple well-being domains at follow-up, controlling for demographics and baseline levels. These findings support the model's criterion validity and temporal stability, confirming its effectiveness in capturing shared and unique aspects of mental health. Conceptually, the bifactor (S-1) approach provides evidence of the independence of flourishing with respect to depressive symptoms, meaning that people with mental illness are able to flourish despite their psychological issues. A practical implication is that notions such as "mental illness prevents people from attaining well-being may be invalid." Many factors mitigate the impact of mental illness. With sufficient social support and psychoeducation, it is possible that people with psychological issues can thrive in society.