Perceived stress as a mediator between chronotype and eating disorder symptoms among college students: Cross-sectional and prospective analyses

The present study aimed to examine whether and how perceived stress mediates the association between chronotype and eating disorder symptoms (ED symptoms), using both cross-sectional and three-wave longitudinal data. A total of 7,892 college students completed three online surveys over one year: 17-29 October 2023 (Time 1, T1),15-24 April 2024 (Time 2, T2), and 16-29 October 2024 (Time 3, T3). Participants completed the reduced version of the Morningness-Eveningness Questionnaire, the 10-item Perceived Stress Scale, the short form of the Eating Disorder Examination Questionnaire, the three items in the Youth Self-Rating Insomnia Scale, and a self-developed demographic questionnaire. Cross-sectional analyses showed that T1 perceived stress partially mediated the relationship between T1 chronotype and T1 ED symptoms, after controlling for demographics and T1 insomnia symptoms. Prospective analyses indicated that T1 chronotype predicted T3 ED symptoms through T2 perceived stress, after controlling for demographics, T1 insomnia symptoms, T1 perceived stress, and T1 ED symptoms. This study highlights perceived stress as a mediator linking chronotype to ED symptoms, suggesting that early identification of evening chronotype and stress-reduction interventions may help prevent ED symptoms in college students.