title: Resting respiratory sinus arrhythmia is related to longer hospitalization in mood-disordered repetitive suicide attempters.
abstract: OBJECTIVE
  Our aims were (1) to measure respiratory sinus arrhythmia (RSA), a high-frequency spectrum component of heart rate variability (HRV) in mood-disordered suicide attempters and (2) to investigate the relationship of RSA to symptoms and length of hospitalization.
  
  
  METHODS
  Forty-nine female repetitive-suicide attempters with depressive disorder or bipolar disorder were recruited in a general hospital setting. Manic or psychotic patients were excluded. Resting RSA values were calculated from electrocardiogram data, and severity of clinical presentation shortly after admission and length of hospital stay were assessed.
  
  
  RESULTS
  RSA was positively associated with a higher Beck Scale for Suicidal Ideation score (r = 0.33 P = 0.019). Stepwise multiple regression analysis showed a significant correlation between RSA and hospitalization length after adjusting other variables (beta coefficient = 3.00; P = 0.030). Patients with a higher resting RSA had more prolonged hospitalizations (hospitalization beyond 30 days) after controlling for other variables (odds ratio = 5.08, P = 0.017).
  
  
  CONCLUSIONS
  Interaction between the environment and the autonomic nervous system is complex. Further and more comprehensive research is needed.
authors.affiliation: Department of Psychiatry, Mackay Memorial Hospital , Taipei , Taiwan.
authors.forename: Ying
authors.initials: Y
authors.lastname: Lin
authors.forename: Chen
authors.initials: C
authors.lastname: Lin
authors.forename: I-Wen
authors.initials: IW
authors.lastname: Sun
authors.forename: Chien-Chi
authors.initials: CC
authors.lastname: Hsu
authors.forename: Chun-Kai
authors.initials: CK
authors.lastname: Fang
authors.forename: Men-Tzung
authors.initials: MT
authors.lastname: Lo
authors.forename: Hui-Chun
authors.initials: HC
authors.lastname: Huang
authors.forename: Shen-Ing
authors.initials: SI
authors.lastname: Liu
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000503:physiopathology*; D003866:Depressive Disorder / Q000503:physiopathology*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D065809:Respiratory Sinus Arrhythmia / Q000502:physiology*; D013406:Suicide, Attempted / Q000706:statistics & numerical data*
keywords: affective disorders; autonomic nervous system; depression; heart rate variability; suicide