Longitudinal associations of sleep midpoint and sleep midpoint variability with the mental health of young adult college students

AI Summary

Later sleep midpoint between participants was strongly associated with higher depression, anxiety and stress scores.
Greater sleep midpoint variability correlated with worse depressive symptoms.
Intervention studies should test whether improving sleep timing and regularity reduces mental health problems in young adult college students.

Chronobiol Int. 2026 May 15:1-7. doi: 10.1080/07420528.2026.2671355. Online ahead of print.

ABSTRACT

Mental health continues to be a growing concern among young adult college students. Prior research has shown that later sleep midpoint and greater sleep midpoint variability were associated with worse mental health, but these studies primarily focused on adolescents and middle- to older-aged adults. The lack of exploration into sleep midpoint and mental health in young adults creates a unique gap in the literature. Therefore, the present study aimed to investigate the longitudinal associations between sleep midpoint and mental health among young adult college students. College students (N = 256) between the ages of 18-26 from two universities recorded their sleep patterns and mental health (PHQ-2, GAD-2, and PSS-4) using electronic daily diaries over 2 weeks. Linear mixed-effects modeling was used to identify how within- and between-person sleep midpoints were associated with mental health outcomes among college students. Between participants, later sleep midpoint was robustly associated with depression (B = 0.19, SE = 0.05, p < 0.001), anxiety (B = 0.21, SE = 0.06, p < 0.001), and stress (B = 0.33, SE = 0.13, p = 0.008). Greater sleep midpoint variability was correlated with worse depressive symptoms (r = 0.14, p = 0.03). Intervention studies need to determine whether addressing sleep timing and sleep regularity could improve young adult mental health.