Reduced heart rate variability in schizophrenia and bipolar disorder compared to healthy controls

Area of Science:

• Psychiatry
• Cardiology
• Autonomic Neuroscience

Background:

• Schizophrenia (SZ) and bipolar disorder (BD) are distinct diagnoses but share clinical and epidemiological features, including elevated cardiovascular disease (CVD) risk.
• Cardiac autonomic nervous system (ANS) dysregulation, assessed via heart rate variability (HRV), is a potential contributor to CVD risk in severe mental illnesses, but its role in SZ and BD is not fully understood.

Purpose of the Study:

• To investigate whether impaired HRV contributes to common CVD risk factors in patients with schizophrenia and bipolar disorder.
• To explore the relationship between HRV and symptom severity in these patient groups.

Main Methods:

• Heart rate variability (HRV) was calculated in 47 patients with SZ, 33 patients with BD, and 212 healthy controls.
• Symptom severity measures were collected from patients diagnosed with SZ or BD.
• Statistical analyses controlled for medication, age, and body mass index.

Main Results:

• Both schizophrenia and bipolar disorder groups exhibited significantly reduced HRV compared to healthy controls.
• No significant differences in HRV were observed between the SZ and BD groups.
• Reduced HRV was independent of medication, age, and BMI.
• Preliminary findings indicated a correlation between reduced HRV and increased overall and negative symptom severity in both SZ and BD patients.

Conclusions:

• Heart rate variability (HRV) may serve as a potential biomarker for CVD risk and symptom severity in severe mental illnesses like schizophrenia and bipolar disorder.
• These findings underscore the necessity of cardiometabolic screening for individuals across the schizophrenia and bipolar disorder spectrum.