title: Sleep and circadian rhythm disruption in schizophrenia.
abstract: BACKGROUND
  Sleep disturbances comparable with insomnia occur in up to 80% of people with schizophrenia, but very little is known about the contribution of circadian coordination to these prevalent disruptions.
  
  
  OBJECTIVE
  A systematic exploration of circadian time patterns in individuals with schizophrenia with recurrent sleep disruption.
  
  
  METHODS
  We examined the relationship between sleep-wake activity, recorded actigraphically over 6 weeks, along with ambient light exposure and simultaneous circadian clock timing, by collecting weekly 48 h profiles of a urinary metabolite of melatonin in 20 out-patients with schizophrenia and 21 healthy control individuals matched for age, gender and being unemployed.
  
  
  RESULTS
  Significant sleep/circadian disruption occurred in all the participants with schizophrenia. Half these individuals showed severe circadian misalignment ranging from phase-advance/delay to non-24 h periods in sleep-wake and melatonin cycles, and the other half showed patterns from excessive sleep to highly irregular and fragmented sleep epochs but with normally timed melatonin production.
  
  
  CONCLUSIONS
  Severe circadian sleep/wake disruptions exist despite stability in mood, mental state and newer antipsychotic treatment. They cannot be explained by the individuals' level of everyday function.
authors.affiliation: Nuffield Laboratory of Ophthalmology, University of Oxford, The John Radcliffe Hospital, Headley Way, Oxford, UK.
authors.forename: Katharina
authors.initials: K
authors.lastname: Wulff
authors.forename: Derk-Jan
authors.initials: DJ
authors.lastname: Dijk
authors.forename: Benita
authors.initials: B
authors.lastname: Middleton
authors.forename: Russell G
authors.initials: RG
authors.lastname: Foster
authors.forename: Eileen M
authors.initials: EM
authors.lastname: Joyce
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008550:Melatonin / Q000652:urine; D018670:Monitoring, Ambulatory; D012559:Schizophrenia / Q000150:complications / Q000503:physiopathology*; D020178:Sleep Disorders, Circadian Rhythm / Q000150:complications / Q000503:physiopathology*; D013997:Time Factors; D014478:Unemployment
chemical_list: D008550:Melatonin