Understanding the impact of changes in perceived stress on mental health is critical for advancing targeted interventions
however, the psychological mechanisms underpinning these processes remain largely unexplored. Grounded in the Dual-Factor System of Mental Health (DFM) and Conservation of Resources (COR) theory, this study explores the intra-individual effects of changes in perceived stress on depression and flourishing, focusing on resources such as meaning in life, perceived social support, and individual autonomy. A total of 1,315 college students were surveyed during the COVID-19 college closures (T1) and subsequent reopening (T2). Latent Change Score Models revealed that only changes in perceived social support and individual autonomy served as protective mediators for changes in depression, while all resources contributed to changes in flourishing. Network analysis further supports the protective role of changes in perceived social support on depression and identifies changes in flourishing as central. These findings enhance our understanding of stress coping by capturing the detailed dynamics of both positive and negative dimensions, while providing actionable insights for developing context-specific resource interventions to address challenges in mental health.