Correlates for Sleep-Wake Patterns among Children and Young Adolescents in Taiwan

Objective: To determine the correlates for sleep-wake patterns. Method: One thousand five hundred and seventy-two students, grade 4 to grade 8, and their parents (response rate =98.4% for student participants and 95.9% for their parents) were recruited using a multistage sampling method. Students completed a Sleep Habit Questionnaire as a classroom exercise and their parents completed it at home. The morning (N = 367) and evening (N = 364) groups were operationally defined as participants with the top 25% and bottom 25% of Morningness/Eveningness (M/E) scale, respectively. Both parametric (linear mixed model) and non- parametric (tree- based classification model) multivariate methods were used to explore the correlates for the sleep- wake patterns. Results: Using backward model selection, we found that being female, being in older school grade levels, increased coffee drinking, being moody, decreased parental monitoring, daytime sleepiness, and several sleep disturbances such as early insomnia, fear of sleep in darkness, bedwetting, and going to bed later than 3 a.m. were associated with decreased M/E scores. The magnitude of association between being moody and evening type was greater in boys than in girls. Being moody, and being in higher school grade levels were the leading factors that distinguished the evening type from the morning type. Conclusions: In addition to school grade level, parental control, sleep problems, sleepiness, and mood status also validate the two extreme M/E groups. The finding that mood status was the leading factor delineating these two groups encourages us to examine the association between being the evening type and having neurotic traits and adolescent psychopathology in future studies in order to provide a guideline for adolescent sleep hygiene.