OBJECTIVES: To investigate the association of insomnia and chronotype preference with daytime impairment and psychopathology in a community sample of adolescents in Hong Kong.
METHODS: This was a cross-sectional study that included seven local secondary schools in Hong Kong. A total of 1667 adolescents (mean age: 14.8 ± 1.6 years old; boys: 56.5%) returned a battery of self-report questionnaires including Insomnia Severity Index (ISI) and reduced Horne and Östberg Morningness and Eveningness Questionnaire (rMEQ) for assessing insomnia symptoms and chronotype preference, respectively. A subset of adolescent samples (n = 768) were additionally assessed for suicidal ideation. Potential confounders including age, gender and sleep duration were controlled for in the analyses.
RESULTS: The prevalence of insomnia symptoms and eveningness chronotype was 37% and 25.6%, respectively. Regression models indicated that insomnia and eveningness were independently associated with excessive daytime sleepiness (insomnia: adjusted OR [AdjOR] = 3.8; 95% confidence interval [C.I.] = 2.9-5.0; eveningness: AdjOR = 2.6; 95% C.I. = 1.9-3.7), and an increased risk of depression (insomnia: AdjOR = 3.5, 95% C.I. = 2.5-5.0; eveningness: AdjOR = 2.0, 95% C.I. = 1.3-3.2). The odds ratio increased to 8.7 (95% C.I. = 6.1-12.3, p < 0.001) for excessive daytime sleepiness and 4.8 (95% C.I. = 3.2-7.2, p < 0.001) for depression among adolescents with both insomnia and eveningness. Insomnia symptoms, but not eveningness, were associated with anxiety symptoms (AdjOR = 5.8; 95% C.I. = 3.6-9.4) and suicidal ideation (AdjOR = 2.1, 95% C.I. = 1.4-3.2).
CONCLUSIONS: The present study provided further evidence that insomnia and eveningness uniquely contributed to poor daytime functioning and mood related outcomes, while the co-existence of these two conditions could confer a greater risk in adolescents. However, insomnia, but not eveningness, was significantly linked to suicidality after controlling for mood symptoms. Our findings highlighted the necessity of timely management of sleep and circadian issues in adolescents.
