Is early-morning class exposure associated with lower positive mental health among university students? Conditional associations and heterogeneous profiles.

BACKGROUND: University is a period of heightened vulnerability for student mental health, yet institutional schedules remain understudied as a modifiable determinant. Drawing on social zeitgeber theory, we tested whether early-morning class exposure is associated with positive mental health through social jetlag and emotion-regulation difficulties, whether bedtime procrastination conditions this association, and whether students' risk configurations are heterogeneous.

METHODS: Data were obtained from 1,437 university students in Sichuan and Yunnan, China. Early-morning class exposure was operationalized as the number of weekdays on which the first class began at or before 08:00. Using partial least squares structural equation modeling with 5,000 bootstrap resamples, we tested direct, indirect, and moderated serial indirect associations while controlling for demographic covariates. Latent profile analysis then identified configurations of these variables, with positive mental health compared across profiles as a distal outcome.

RESULTS: More frequent early-morning class exposure was associated with lower positive mental health (total effect β = -0.270, 95% CI [-0.316, -0.221]). This association operated partly through a serial indirect association: greater exposure predicted more social jetlag, which predicted more emotion-regulation difficulties. Emotion-regulation difficulties alone did not mediate the association independently. Bedtime procrastination amplified this process, strengthening the exposure-jetlag link at higher levels of procrastination (interaction β = 0.451, 95% CI [0.413, 0.489]). Latent profile analysis identified five distinct risk configurations: students combining frequent classes with stable sleep and effective emotion regulation reported the highest positive mental health, whereas those with co-occurring emotion-regulation difficulties and elevated schedule risk reported the lowest.

CONCLUSIONS: These findings extend social zeitgeber theory to institutional course scheduling, showing that early-morning classes relate to students' positive mental health through a sequential temporal-psychological process that bedtime procrastination can intensify. Supporting student mental health may require attending jointly to institutional schedule design and individual sleep regulation, pending confirmation from longitudinal and objective-data designs.