title: Sleep in remitted bipolar disorder: a naturalistic case-control study using actigraphy.
abstract: BACKGROUND
  Findings from actigraphic studies suggesting that sleep and circadian rhythms are disrupted in bipolar disorder (BD) patients have been undermined by methodological heterogeneity and the failure to adequately address potential confounders.
  
  
  METHODS
  Twenty-six euthymic BD cases and 29 healthy controls (HC), recruited from University Paris-Est and matched for age and gender, were compared on subjective (Pittsburgh Sleep Questionnaire Inventory; PQSI) and objective (mean scores and variability in actigraphy) measures of sleep as recorded by over 21 consecutive days.
  
  
  RESULTS
  Multivariate generalized linear modelling (GLM) revealed significant differences between BD cases and HC for five PSQI items (total score and four subscales), four actigraphy variables (mean scores) and five actigraphy variability measures. Backward stepwise linear regression (BSLR) indicated that a combination of four variables (mean sleep duration, mean sleep latency, variability of the fragmentation index over 21 days, and mean score on PSQI daytime dysfunction sub-scale) correctly classified 89% of study participants as cases or controls (Chi-square=39.81; df=6; p=0.001).
  
  
  CONCLUSIONS
  The sample size (although larger than most actigraphy studies) and incomplete matching of cases and controls may have influenced our findings. It was not possible to control for potential effects of psychotropic medication or differences in employment status between groups.
  
  
  CONCLUSIONS
  When potential confounders of sleep and circadian profiles are adequately taken into account (particularly age, gender, daytime sleepiness, mood symptoms, body mass index, and risk of sleep apnoea), a selected subset of quantitative (mean scores) and qualitative (variability) features differentiated euthymic BD cases from HC.
authors.affiliation: INSERM, U955, Psychiatrie génétique, Créteil 94000, France; AP-HP, Hôpital H. Mondor - A. Chenevier, Pôle de Psychiatrie, Créteil 94000, France; Pôle de psychiatrie, Université Lille Nord de France, CHRU de Lille, F-59000 Lille, France; Fondation FondaMental, Créteil 94000, France. Electronic address: pierre.a.geoffroy@gmail.com.
authors.forename: Pierre Alexis
authors.initials: PA
authors.lastname: Geoffroy
authors.affiliation: INSERM, U955, Psychiatrie génétique, Créteil 94000, France; AP-HP, Hôpital H. Mondor - A. Chenevier, Pôle de Psychiatrie, Créteil 94000, France; Fondation FondaMental, Créteil 94000, France.
authors.forename: Carole
authors.initials: C
authors.lastname: Boudebesse
authors.affiliation: Fondation FondaMental, Créteil 94000, France; AP-HP, GH Saint-Louis, Lariboisière, Fernand Widal, Pôle Neurosciences, Paris, France; Université Paris-7 Paris-Diderot, UFR de Médecine, Paris, France.
authors.forename: Frank
authors.initials: F
authors.lastname: Bellivier
authors.affiliation: INSERM, U955, Psychiatrie génétique, Créteil 94000, France.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Lajnef
authors.affiliation: INSERM, U955, Psychiatrie génétique, Créteil 94000, France; Université Paris Est, Faculté de médecine, Créteil 94000, France; AP-HP, Hôpital H. Mondor - A. Chenevier, Pôle de Psychiatrie, Créteil 94000, France; Fondation FondaMental, Créteil 94000, France.
authors.forename: Chantal
authors.initials: C
authors.lastname: Henry
authors.affiliation: INSERM, U955, Psychiatrie génétique, Créteil 94000, France; Université Paris Est, Faculté de médecine, Créteil 94000, France; AP-HP, Hôpital H. Mondor - A. Chenevier, Pôle de Psychiatrie, Créteil 94000, France; Fondation FondaMental, Créteil 94000, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Leboyer
authors.affiliation: Academic Psychiatry, Institute of Neuroscience, Newcastle University, UK; Centre for Affective Disorders, Institute of Psychiatry, London, UK.
authors.forename: Jan
authors.initials: J
authors.lastname: Scott
authors.affiliation: INSERM, U955, Psychiatrie génétique, Créteil 94000, France; AP-HP, Hôpital H. Mondor - A. Chenevier, Pôle de Psychiatrie, Créteil 94000, France; Fondation FondaMental, Créteil 94000, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Etain
mesh_terms: D056044:Actigraphy; D000328:Adult; D001714:Bipolar Disorder / Q000503:physiopathology*; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000175:diagnosis*; D011795:Surveys and Questionnaires
keywords: Actigraphy; Bipolar disorder; Circadian rhythms; Euthymia; Remission; Sleep