title: Biological rhythms are independently associated with quality of life in bipolar disorder.
abstract: BACKGROUND
  Evidence suggests that patients with bipolar disorder (BD) experience biological rhythm disturbances; however, no studies have examined the impact of this disruption on quality of life (QOL). The aim of this study is to investigate the influence of biological rhythm, depressive symptoms, sleep quality, and sleep medication use on QOL in BD.
  
  
  METHODS
  Eighty BD subjects (44 depressed and 36 euthymic) completed questionnaires assessing QOL (WHOQOL-BREF), biological rhythm disruption (BRIAN), depressive symptoms (MADRS), and sleep quality (PSQI). The impact of biological rhythm disturbance, depressive symptoms severity, sleep quality, and sleep medication use on QOL was determined with multiple regression analyses.
  
  
  RESULTS
  BRIAN (β = -0.31, t = -2.73, p < 0.01), MADRS (β = -0.30, t = -2.93, p < 0.01), and sleep medication use (β = -0.45, t = -2.55, p < 0.05) were significant predictors of QOL in this model (F 4, 75 = 20.28; p < 0.0001). The relationship of these factors with subdomains of QOL showed that poorer social QOL was associated with greater biological rhythm disturbance (β = -0.43, t = -3.66, p < 0.01) and sleep medication use (β = -0.49, t = -2.35, p < 0.01), providing support for the social rhythm theory of BD. Physical QOL was associated with depression (β = -0.30, t = -2.93, p < 0.01) and biological rhythm disruption (β = -0.31, t = -2.73, p < 0.01). Main limitations include the cross-sectional assessment and the lack of objective measures of biological rhythms in relation to QOL.
  
  
  CONCLUSIONS
  Disruption in biological rhythm is associated with poor QOL in BD, independent of sleep disturbance, sleep medication use, and severity of depression. Treatment strategies targeting regulation of biological rhythms, such as sleep/wake cycles, eating patterns, activities, and social rhythms, are likely to improve QOL in this population.
authors.affiliation: Mood Disorders Program, St. Joseph's Healthcare Hamilton, 100 West 5th St, Room C124, Hamilton, ON, L8N 3K7, Canada.|Women's Health Concerns Clinic, St. Joseph's Healthcare Hamilton, Hamilton, ON, Canada.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Cudney
authors.affiliation: Mood Disorders Program, St. Joseph's Healthcare Hamilton, 100 West 5th St, Room C124, Hamilton, ON, L8N 3K7, Canada. freybn@mcmaster.ca.|Women's Health Concerns Clinic, St. Joseph's Healthcare Hamilton, Hamilton, ON, Canada. freybn@mcmaster.ca.|Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada. freybn@mcmaster.ca.
authors.forename: Benicio N
authors.initials: BN
authors.lastname: Frey
authors.affiliation: Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.|Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
authors.forename: David L
authors.initials: DL
authors.lastname: Streiner
authors.affiliation: Mood Disorders Program, St. Joseph's Healthcare Hamilton, 100 West 5th St, Room C124, Hamilton, ON, L8N 3K7, Canada.|Women's Health Concerns Clinic, St. Joseph's Healthcare Hamilton, Hamilton, ON, Canada.|Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
authors.forename: Luciano
authors.initials: L
authors.lastname: Minuzzi
authors.affiliation: Mood Disorders Program, St. Joseph's Healthcare Hamilton, 100 West 5th St, Room C124, Hamilton, ON, L8N 3K7, Canada.|Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.
authors.forename: Roberto B
authors.initials: RB
authors.lastname: Sassi
keywords: Bipolar disorder; Circadian rhythm; Quality of life; Sleep