Social Support and Mental Health Across a Public Health Crisis Lifecycle: A Three-Wave Repeated Cross-Sectional Study of Mediating Coping Mechanisms.

OBJECTIVE: Adopting a full crisis-lifecycle perspective, this study investigates the underlying mechanism through which social support influences college students' mental health (with psychological symptoms as the core measurement indicator) via the mediating role of coping styles in major public health emergencies, and examines population-level cross-phase associations of this mechanism across three core phases of the crisis lifecycle: the emergency phase, adaptation phase, and reconstruction phase. METHODS: Taking the COVID-19 pandemic as a natural experimental setting for the full crisis lifecycle, this study conducted a five-year, three-wave repeated cross-sectional survey with independent samples of participants in 2020, 2023, and 2025, enrolling a total of 2958 college students. Participants were assessed using the Social Support Rating Scale (SSRS), Simplified Coping Style Questionnaire (SCSQ), and Psychological Questionnaires for Emergent Events of Public Health, (PQEEPH). Structural equation modeling and multi-group analyses were applied to cross-phase validation of the dual-path mediating model of coping styles. RESULTS: (1) The direct association between social support and mental health was statistically significant across all three phases (all p < 0.01), with no statistically significant difference among the three phases (p > 0.05). (2) The mediating effect of positive coping between social support and mental health was significant across all three phases (all p < 0.05), and the mediating effect of positive coping showed a progressive increasing trend across phases, with a marginally significant difference observed between the emergency and reconstruction phases (β = 0.081, p < 0.05). (3) The mediating effect of negative coping between social support and mental health was significant across all three phases (all p < 0.05), with no significant temporal difference among the three phases (p > 0.05). CONCLUSION: Throughout the full lifecycle of major public health emergencies, the effects of social support on mental health exhibit asynchronous cross-phase patterns at the population level: the direct effect remains stable across phases, the mediating pathway of positive coping shows a progressive increase across the three phases, with the largest effect observed in the reconstruction phase, while the mediating effect of negative coping remains stable across phases.