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Journal Article Ppublish

PubMed: 42632380 DOI: 10.1016/j.sleep.2026.109227

Chronotype and insomnia symptoms in the incidence and persistence of depressive symptoms: An 8-year longitudinal cohort study.

Sleep Med 148:109227

Authors: Yuta Takano, Isa Okajima, Yukiyoshi Sumi, Hiroshi Kadotani

Affiliations

  • Department of Somnology, Tokyo Medical University, Tokyo, Japan; Japan Sleep Center, Institute of Neuropsychiatry, Tokyo, Japan; Department of Psychiatry, Shiga University of Medical Science, Shiga, Japan.
  • Japan Sleep Center, Institute of Neuropsychiatry, Tokyo, Japan; Department of Psychiatry, Shiga University of Medical Science, Shiga, Japan; Behavioral Sleep Medicine and Sciences Laboratory, Department of Psychological Counseling, Faculty of Humanities, Tokyo Kasei University, Tokyo, Japan.
  • Department of Psychiatry, Shiga University of Medical Science, Shiga, Japan.

Abstract

BACKGROUND

Previous research findings on the association between chronotype and depressive symptoms have relied on cross-sectional studies, and the temporal relationship remains unclear. This study aimed to examine whether insomnia symptoms modify the longitudinal association between chronotype and depressive symptoms.

METHODS

This study was an 8-year longitudinal study of 1549 adults who completed the baseline survey. Insomnia symptoms and chronotype were assessed using the Insomnia Severity Index and the Circadian Energy Scale. The presence of depressive symptoms was defined as a Patient Health Questionnaire-9 score of 10 or higher.

RESULTS

Evening chronotype and insomnia symptoms were associated with depressive symptoms (evening: odds ratio [OR] = 1.73, 95% confidence interval [CI] = 1.08 to 2.78; insomnia symptoms: OR = 4.78, 95% CI = 3.89 to 5.87). In the incidence of depressive symptoms, the interaction between chronotype and insomnia symptoms was significant, with the presence of insomnia symptoms increasing the risk across all chronotypes (morning: relative risk [RR] = 5.20, 95% CI = 1.97 to 13.75, risk difference [RD] = 15.73%; intermediate: RR = 3.39, 95% CI = 2.54 to 4.52, RD = 12.04%; evening: RR = 1.70, 95% CI = 1.11 to 2.59, RD = 7.28%). In the persistence of depressive symptoms, only insomnia symptoms were significant (RR = 1.74, 95% CI [1.34, 2.27], RD = 18.67%).

CONCLUSIONS

These findings suggest that the association between chronotype and depressive symptoms differs by insomnia status and is specific to the incidence of depressive symptoms, but not the persistence of depressive symptoms.

MeSH

Patient Health Questionnaire, Incidence, Cohort Studies, Signs And Symptoms, Sleep Initiation And Maintenance Disorders, Sleep Wake Disorders