title: Correlates of sleep-wake patterns among children and young adolescents in Taiwan.
abstract: OBJECTIVE
  To determine correlates of morning and evening sleep-wake patterns in a community sample of children.
  
  
  METHODS
  A school-based cross-sectional survey.
  
  
  METHODS
  Sample included 1572 students, grades 4 to 8 (response rate, 98.4%), using a multistage sampling method.
  
  
  METHODS
  N/A.
  
  
  RESULTS
  Student participants completed a Sleep Habits Questionnaire, which included sleep schedules, a mood scale, substance use, the morningness/eveningness (M/E) scale, pubertal development scale, sleep disturbance scale, and parental monitoring scale. The morning (n = 367) and evening (n = 364) groups were operationally defined as participants who scored in the top or bottom 25% of the M/E scale, respectively. Linear mixed and tree-based classification models were used to explore correlates of sleep-wake patterns. Our results showed the evening type was associated with older school grade level, increased coffee drinking, moodiness, decreased parental monitoring, daytime sleepiness, and several sleep disturbances, including early insomnia, fear of sleeping in darkness, bedwetting, and going to bed later than 3 am. The 2 most potent discriminators between evening and morning subtypes were higher grade level, an index of age, and moodiness. The association of moodiness with the evening type was greater in boys than girls.
  
  
  CONCLUSIONS
  These findings suggest that further research should address explanations for the association between evening type and mood and anxiety symptoms, including order of the effects, developmental factors, environmental determinants of sleep time such as school start time and parental bedtime monitoring, and circadian maturation.
authors.affiliation: Department of Psychiatry, National Taiwan University Hospital, and Department of Psychiatry, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC. gaushufe@ntu.edu.tw
authors.forename: Susan Shur-Fen
authors.initials: SS
authors.lastname: Gau
authors.forename: Wei-Tsuen
authors.initials: WT
authors.lastname: Soong
authors.forename: Kathleen R
authors.initials: KR
authors.lastname: Merikangas
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D000697:Central Nervous System Stimulants / Q000008:administration & dosage; D002648:Child; D002940:Circadian Rhythm / Q000502:physiology; D003069:Coffee; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D019964:Mood Disorders / Q000175:diagnosis / Q000453:epidemiology; D015588:Observer Variation; D012044:Regression Analysis; D017678:Sex Distribution; D020178:Sleep Disorders, Circadian Rhythm / Q000453:epidemiology / Q000208:ethnology*; D011795:Surveys and Questionnaires; D013624:Taiwan
chemical_list: D000697:Central Nervous System Stimulants; D003069:Coffee