Is it a vicious circle and for whom? The reciprocal association between rumination and somatic symptoms and moderation by stress: A daily diary study among Chinese college students

College students who experienced somatic symptoms during the COVID-19 pandemic may engage in rumination, but their bidirectional nature remains underexplored. Symptom perception theory suggests a reciprocal relationship between rumination and somatic symptoms, and the multiple-stressor perspective and the perseverative cognition hypothesis assume that the reciprocal association might be exacerbated by high stress. In this study, we examined temporal associations between rumination and somatic symptoms and variations by patterns of stress related to COVID-19 and daily hassles. A total of 582 Chinese college students provided daily reports on rumination, somatic symptoms, COVID-related stress, and daily hassles for seven consecutive days in November 2020. A cross-lagged panel model showed a positive reciprocal association between rumination and somatic symptoms. Greater rumination predicted more next-day somatic symptoms, and more somatic symptoms increased next-day rumination. Dual trajectory analysis identified four stress patterns of COVID-related stress and daily hassles (i.e. low-low, low-high, high-low, and high-high), and multi-group analysis found the reciprocal association only presented in the high-high group. Our findings indicate a vicious circle between rumination and somatic symptoms that is dependent on heterogeneous stress patterns. Attention should be paid to the high-risk group with both high levels of COVID-related stress and daily hassles.