title: Delayed sleep phase disorder in an Australian school-based sample of adolescents.
abstract: OBJECTIVE
  To establish the extent to which the developmental changes in sleep timing experienced by Australian adolescents meet the International Classification of Sleep Disorders (ICSD-2) diagnostic criteria for delayed sleep phase disorder (DSPD), and whether adolescents with DSPD engage in poorer lifestyle choices, and are more impaired compared to good sleeping adolescents.
  
  
  METHODS
  Three-hundred seventy-four Australian adolescents (mean age 15.6 years, SD 1.0) participants completed a 7-day sleep diary, wore wrist actigraphy, and completed a battery of questionnaires to assess DSPD criteria.
  
  
  RESULTS
  The ICSD-2 criteria for DSPD were met by 1.1% (N = 4) of the adolescents sampled. The majority of adolescents (51.9%, N = 194) met one criterion, 14% (N = 52) of the adolescents met 2 criteria, while 33.2% (N = 124) did not fulfill any DSPD criteria. Despite having significantly delayed sleep timing, adolescents who met all criteria for DSPD reported similar lifestyle habits and daytime functioning. However, there were trends for greater alcohol and caffeine consumption, less sport participation, yet more time spent on extracurricular activities (i.e., learning to play a musical instruments for adolescents with DSPD.
  
  
  CONCLUSIONS
  Despite the majority of adolescents reporting DSPD symptoms, only a small minority met full diagnostic criteria. Adolescents with DSPD reported similar lifestyle habits and daytime functioning to those with some or no symptoms. Future investigations of non-school-attending DSPD adolescents are needed to confirm the trends for lifestyle behaviors found in the present study.
authors.affiliation: School of Psychology, Flinders University, Adelaide, S.A., Australia. nicole.lovato@flinders.edu.au
authors.forename: Nicole
authors.initials: N
authors.lastname: Lovato
authors.forename: Michael
authors.initials: M
authors.lastname: Gradisar
authors.forename: Michelle
authors.initials: M
authors.lastname: Short
authors.forename: Hayley
authors.initials: H
authors.lastname: Dohnt
authors.forename: Gorica
authors.initials: G
authors.lastname: Micic
mesh_terms: D056044:Actigraphy; D000293:Adolescent; D000367:Age Factors; D001315:Australia / Q000453:epidemiology; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D020178:Sleep Disorders, Circadian Rhythm / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D011795:Surveys and Questionnaires
keywords: Adolescents; ICSD-2; daytime functioning; delayed sleep phase disorder