title: Dose-dependent effect of antipsychotic drugs on autonomic nervous system activity in schizophrenia.
abstract: BACKGROUND
  Antipsychotic drugs are considered a trigger factor for autonomic dysregulation, which has been shown to predict potentially fatal arrhythmias in schizophrenia. However, the dose-dependent effect of antipsychotic drugs and other psychotropic drugs on autonomic nervous system (ANS) activity remain unclear. The purpose of this study was to investigate the dose-dependent effect of antipsychotic drugs and other clinical factors on ANS activity in an adequate sample size of patients with schizophrenia.
  
  
  METHODS
  A total of 211 Japanese patients with schizophrenia and 44 healthy subjects participated in this study. ANS activity was assessed by means of heart rate variability (HRV) power spectral analysis. Antipsychotic drug treatment and various clinical factors were investigated for each participant. The patient group was categorized into three subgroups according to daily dose of antipsychotic drug, and HRV was compared between groups.
  
  
  RESULTS
  The results showed significantly decreased low-frequency and high-frequency components of HRV in the patient group compared to the control group. The high-dose group showed a significantly lower HRV than the medium-dose group and an even lower HRV than the low-dose group. In addition, a significant association between HRV and antipsychotic drug dose was identified by multiple regression analysis. HRV was not associated with age, sex, body mass index, duration of illness, or daily dose of other psychotropic drugs.
  
  
  CONCLUSIONS
  These results suggest that antipsychotic drugs exert a significant dose-dependent effect on the extent of decline in ANS activity, and that optimal antipsychotic medication is required to avoid possible cardiovascular adverse events in patients with schizophrenia.
authors.affiliation: Department of Psychiatry, Yokohama City University School of Medicine, 3-9, Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.
authors.forename: Yohko
authors.initials: Y
authors.lastname: Iwamoto
authors.forename: Chiaki
authors.initials: C
authors.lastname: Kawanishi
authors.forename: Ikuko
authors.initials: I
authors.lastname: Kishida
authors.forename: Taku
authors.initials: T
authors.lastname: Furuno
authors.forename: Mami
authors.initials: M
authors.lastname: Fujibayashi
authors.forename: Chie
authors.initials: C
authors.lastname: Ishii
authors.forename: Norio
authors.initials: N
authors.lastname: Ishii
authors.forename: Toshio
authors.initials: T
authors.lastname: Moritani
authors.forename: Masataka
authors.initials: M
authors.lastname: Taguri
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Hirayasu
mesh_terms: D000328:Adult; D000368:Aged; D014150:Antipsychotic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001341:Autonomic Nervous System / Q000187:drug effects* / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000295:instrumentation / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D014150:Antipsychotic Agents