title: Reduced heart rate variability in schizophrenia and bipolar disorder compared to healthy controls.
abstract: OBJECTIVE
  Despite current diagnostic systems distinguishing schizophrenia (SZ) and bipolar disorder (BD) as separate diseases, emerging evidence suggests they share a number of clinical and epidemiological features, such as increased cardiovascular disease (CVD) risk. It is not well understood if poor cardiac autonomic nervous system regulation, which can be indexed non-invasively by the calculation of heart rate variability (HRV), contributes to these common CVD risk factors in both diseases.
  
  
  METHODS
  We calculated HRV in 47 patients with SZ, 33 patients with BD and 212 healthy controls. Measures of symptom severity were also collected from the patient groups.
  
  
  RESULTS
  Heart rate variability was significantly reduced in both these disorders in comparison with the healthy participants; however, there were no HRV differences between disorders. Importantly, these reductions were independent of the medication, age or body mass index effects. There was also preliminary evidence that patients with reduced HRV had increased overall and negative psychosis symptom severity regardless of SZ or BD diagnosis.
  
  
  CONCLUSIONS
  We suggest that HRV may provide a possible biomarker of CVD risk and symptom severity in severe mental illness. Thus, our results highlight the importance of cardiometabolic screening across SZ and bipolar spectrum disorders.
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: D S
authors.initials: DS
authors.lastname: Quintana
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, University of Oslo, Oslo, Norway.|Department of Psychology, University of Oslo, Oslo, Norway.
authors.forename: L T
authors.initials: LT
authors.lastname: Westlye
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Kaufmann
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: Ø G
authors.initials: ØG
authors.lastname: Rustan
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: C L
authors.initials: CL
authors.lastname: Brandt
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: B
authors.initials: B
authors.lastname: Haatveit
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, University of Oslo, Oslo, Norway.|Drammen Outpatient Clinic, Clinic of Mental Health and Addiction, Vestre Viken Hospital Trust, Drammen, Norway.
authors.forename: N E
authors.initials: NE
authors.lastname: Steen
authors.affiliation: NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital, University of Oslo, Oslo, Norway.
authors.forename: O A
authors.initials: OA
authors.lastname: Andreassen
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology; D001714:Bipolar Disorder / Q000503:physiopathology*; D002318:Cardiovascular Diseases / Q000503:physiopathology / Q000523:psychology*; D016022:Case-Control Studies; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D012307:Risk Factors; D012559:Schizophrenia / Q000503:physiopathology*; D012720:Severity of Illness Index
keywords: autonomic nervous system; bipolar disorder; heart rate variability; schizophrenia