Sleep variability, eveningness and depression in adolescents: a case-control study

Yue Pan, Forrest Tin Wai Cheung, Dandan Liao, Fiona Yujing Jin, Joey Wing Yan Chan, Ngan Yin Chan, Yun Kwok Wing, Xiaoqing Hu, Shirley Xin Li

Abstract

Introduction: Adolescence is characterized by a circadian shift towards eveningness and changes in sleep pattern. This period is also often associated with an increased incidence of psychopathology, such as depression. Greater intraindividual sleep variability has been linked to both eveningness and depression. However, limited research has explored the interplay between eveningness and depression in relation to sleep variability in youth. The present case-control study aimed to investigate sleep variability in adolescents with eveningness and/or depression, as well as to explore the correlates of sleep variability.

Materials and methods: Four groups of adolescents aged 12-20 years were recruited: eveningness and depression group (ED), eveningness only group (E), depression only group (D), and healthy controls. Eveningness was defined as a score of ≤ 41 on the Morningness-Eveningness Questionnaire. Depression groups met DSM-5 criteria for major depressive disorder or dysthymia. Participants completed a 7-day sleep dairy with actigraphy monitoring and self-reported questionnaires to assess circadian preference, insomnia symptoms, depressive symptoms, and bedtime procrastination. Subjective and objective sleep variabilities were calculated using root mean squared successive differences from sleep diary and actigraphy data, respectively.

Results: A total of 95 participants (mean age: 17.82 s.d. 1.59 years, 76% female) were included in the analysis (ED: n = 23, E: n = 26, D: n = 25, C: n = 21). Both ED and D groups showed significantly more severe depressive symptoms compared to E and C groups (all ps < .001). ED group showed greater variability in time in bed (vTIB) compared to D group (sleep diary: p = .033; actigraphy: p = .040) and controls (sleep diary: p = .025; actigraphy: p = .013). ED group also showed greater variability in sleep offset (vSOFF) and rise time (vRT) as measured by sleep diary compared to D group (SOFF: p = .009; RT: p = .004) and controls (SOFF: p = .037; RT: p = .012). ED group showed greater variability in sleep offset as measured by actigraphy compared to E group (p = .034), D group (p = .005), and controls (p < .001). E group showed greater variability in time in bed as measured by actigraphy (p = .026) compared to controls. Regression analyses showed that stronger eveningness preference was independently associated with greater sleep variability in TIB, TST, and RT as measured by sleep diary, and TIB as measured by actigraphy (all ps < .05). No other associations were found between sleep variability parameters and insomnia symptoms, depressive symptoms, or bedtime procrastination.

Conclusions: The present study suggested a synergetic effect of eveningness and depression on increasing sleep variability in adolescents. Evening preference was independently associated with greater sleep variability. Future research may consider adopting a longitudinal design to further elucidate the relationships between sleep variability, chronotype preference and depression and to explore the effects of circadian-focused interventions on reducing sleep variability and depressive symptoms in youth.

Acknowledgments: This work was supported by the General Research Fund from the Hong Kong Research Grants Council (Ref. 17615722) and the Seed Fund for Basic Research (University Research Committee, The University of Hong Kong).

Recommended citation: Pan, Y., Cheung, F. T. W., Liao, D.-D., Jin, F. Y., Chan, J. W.-Y., Chan, N. Y., Wing, Y.-K., & Li, S. X. (2026). Sleep variability, eveningness and depression in adolescents: a case-control study. Sleep Medicine, 138, 107155. https://doi.org/10.1016/j.sleep.2025.107155