title: Familiality and clinical outcomes of sleep disturbances in major depressive and bipolar disorders.
abstract: OBJECTIVE
  Sleep disturbances are frequently observed in major depressive (MDD) and bipolar disorder (BD). This study reported sleep profiles of patients and their relatives versus controls, and examined the familiality of sleep features in mood disorder families. We also evaluated the influences of sleep disturbance on patients' quality of life (QOL), functional impairment, and suicidality.
  
  
  METHODS
  We recruited 363 BD and 157 MDD patients, 521 first-degree relatives, and 235 healthy controls, which completed a diagnostic interview, Pittsburgh Sleep Quality Index (PSQI), and QOL questionnaire. The magnitude of heritability of sleep features was calculated and familiality was evaluated by mixed regression models and intraclass correlation coefficient (ICC). The associations between sleep problems and clinical outcomes were examined using multiple regression models.
  
  
  RESULTS
  More than three-quarters of mildly-ill patients were classified as "poor sleepers". MDD patients had significantly worse sleep quality as compared to BD patients. Moderate but significant familial aggregation was observed in subjective sleep quality, sleep latency, disturbance, daytime dysfunction, and global score (ICC=0.10-0.21, P<.05). Significant heritability was found in sleep quality (0.45, P<.001) and sleep disturbance (0.23, P<.001). Patients with good sleep quality had better QOL and less functional impairment (P<.05) than poor sleepers. Poor sleep quality and nightmares further increased the risk for suicidal ideation (ORadj=2.8) and suicide attempts (ORadj=1.9-2.8).
  
  
  CONCLUSIONS
  Subjectively measured sleep features demonstrated significant familiality. Poor sleep quality further impaired patients' daily function and QOL, in addition to increasing the risk of suicidality, and thus requires special attention in related clinical settings.
authors.affiliation: Department of Public Health & Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan.
authors.forename: Yin-Chieh
authors.initials: YC
authors.lastname: Lai
authors.affiliation: Department of Psychiatry, Taipei City Psychiatric Center, Taipei City Hospital, Taipei, Taiwan; Department of Psychiatry, School of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Ming-Chyi
authors.initials: MC
authors.lastname: Huang
authors.affiliation: Department of Psychiatry & Center of Sleep Disorders, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Hsi-Chung
authors.initials: HC
authors.lastname: Chen
authors.affiliation: Department of Psychiatry, Chi Mei Medical Center, Tainan, Taiwan.
authors.forename: Ming-Kun
authors.initials: MK
authors.lastname: Lu
authors.affiliation: Department of Psychiatry, Taipei Medical University-Wan Fang Medical Center, Taipei, Taiwan.
authors.forename: Yi-Hang
authors.initials: YH
authors.lastname: Chiu
authors.affiliation: Department of Psychiatry, Taipei Medical University-Wan Fang Medical Center, Taipei, Taiwan.
authors.forename: Winston W
authors.initials: WW
authors.lastname: Shen
authors.affiliation: Department of Psychiatry, National Cheng Kung University Hospital, Tainan, Taiwan.
authors.forename: Ru-Band
authors.initials: RB
authors.lastname: Lu
authors.affiliation: Department of Public Health & Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan. Electronic address: phkuo@ntu.edu.tw.
authors.forename: Po-Hsiu
authors.initials: PH
authors.lastname: Kuo
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000150:complications*; D003865:Major Depressive Disorder / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D012189:Retrospective Studies; D012306:Risk; D012890:Sleep; D012893:Sleep Wake Disorders / Q000523:psychology*; D059020:Suicidal Ideation; D013406:Suicide, Attempted / Q000523:psychology; D011795:Surveys and Questionnaires
keywords: Bipolar disorder; Familial aggregation; Major depressive disorder; Quality of life; Sleep disturbance