title: Reduced cardiac autonomic response to deep breathing: A heritable vulnerability trait in patients with schizophrenia and their healthy first-degree relatives.
abstract: Reduced resting heart rate variability (HRV) has been observed in patients with schizophrenia and their relatives, suggesting genetic predispositions. However, findings have not been consistent. We assessed cardiac autonomic response to deep breathing in first-degree relatives of patients with schizophrenia (n=45; 26 female; aged 39.69±14.82 years). Data were compared to healthy controls (n=45; 26 female; aged 38.27±9.79 years) matched for age, gender, body mass index and physical activity as well as to unmedicated patients with acute schizophrenia (n=45; 25 female; aged 37.31±12.65 years). Electrocardiograms were recorded under supine resting and deep-breathing conditions (10-12breaths/min). We measured HRV components including variance, low-frequency (LF) power, which may reflect baroreflex function, high-frequency (HF) power, which reflects cardiac parasympathetic activity, and LF/HF ratio, which may reflect sympatho-vagal balance. Patients rather than relatives exhibited lower resting-state HRV (variance, LF, and HF) than controls. As expected, deep breathing induced an increase in variance and HF-HRV in controls. However, such a response was significantly reduced in both patients and their relatives. In conclusion, the diminished cardiac autonomic reactivity to deep breathing seen in patients and their unaffected relatives indicates that this pattern of cardiac autonomic dysregulation may be regarded as a genetic trait marker for schizophrenia.
authors.affiliation: Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Liu
authors.affiliation: Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan; Student Counseling Center, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Nian-Sheng
authors.initials: NS
authors.lastname: Tzeng
authors.affiliation: Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Chin-Bin
authors.initials: CB
authors.lastname: Yeh
authors.affiliation: Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Terry B J
authors.initials: TB
authors.lastname: Kuo
authors.affiliation: Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: San-Yuan
authors.initials: SY
authors.lastname: Huang
authors.affiliation: Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. Electronic address: chang.ha@mail.ndmctsgh.edu.tw.
authors.forename: Chuan-Chia
authors.initials: CC
authors.lastname: Chang
authors.affiliation: Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. Electronic address: chang.ha@mail.ndmctsgh.edu.tw.
authors.forename: Hsin-An
authors.initials: HA
authors.lastname: Chang
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology*; D004562:Electrocardiography / Q000639:trends; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019655:Quantitative Trait, Heritable; D012119:Respiration / Q000235:genetics*; D012559:Schizophrenia / Q000175:diagnosis / Q000503:physiopathology*
keywords: Cardiac autonomic response; Deep breathing; First-degree relatives; Heart rate variability; Schizophrenia