Comparative Study of Heart Rate Variability in Patients with Schizophrenia, Bipolar Disorder, Post-traumatic Stress Disorder, or Major Depressive Disorder

Abstract

Objective: Heart rate variability (HRV) changes as a function of psychiatric illness. This study aimed to evaluate HRV among patients with various psychiatric disorders.

Methods: The present study recruited patients with schizophrenia (n=35), bipolar disorder (n=41), post-traumatic stress disorder (PTSD; n=34), or major depressive disorder (n=34) as well as healthy controls (n=27). The time-domain analysis (the standard deviation of all RR intervals [SDNN] and the square root of the mean squared differences of successive normal sinus intervals [RMSSD]), the frequency-domain analysis (very low frequency, low frequency [LF], high frequency [HF], and total power [TP]), and a non-linear complexity measure the approximate entropy were computed.

Results: SDNN and HF were significantly reduced in patients with schizophrenia compared with healthy controls. SDNN, RMSSD, TP, LF, and HF were significantly reduced in bipolar patients compared with healthy controls. HF was significantly reduced in PTSD patients compared with healthy controls.

Conclusion: Our findings indicate that HRV is not sufficiently powerful to discriminate among various psychiatric illnesses. However, our results suggest that HRV, particularly HF, could be used as a tool for discriminating between psychiatric patients and healthy controls.

Keywords: Bipolar disorder; Heart rate variability; Major depressive disorder; Post traumatic stress disorder; Schizophrenia.

Fig. 1

Time domain analysis of heart rate variability (HRV) index. The standard deviation of all RR intervals (SDNN) of schizophrenia and bipolar disorder were significantly reduced compared to healthy controls. The square root of the mean squared differences of successive normal sinus intervals (RMSSD) of bipolar disorder was significantly reduced compared to healthy controls. ^*Significant differences compared to healthy controls (p<0.05). PTSD, post-traumatic stress disorder; MDD, major depressive disorder.

Fig. 2

Frequency domain analysis of HRV index. The spectral power of low frequency (LF) of bipolar disorder was significantly reduced compared to healthy controls. The spectral power of high frequency (HF) of schizophrenia, bipolar disorder, post-traumatic stress disorder (PTSD), and major depressive disorder (MDD) were significantly reduced compared to healthy controls. The spectral power of total power (TP) of bipolar disorder was significantly reduced compared to healthy controls. ^*Significant differences compared to healthy controls (p<0.05).