The influence of medical treatment on non-linear complexity measures of autonomic regulation of heart rate variability in patients with acute schizophrenia

Cardiovascular mortality is up to three times higher in patients with schizophrenia than in general population suggesting a cardiac autonomic dysregulation. Possible mechanisms which could be contribute to the increased mortality rates are under discussion. Aim of this study was to investigate the influence of acute schizophrenia with and without medical treatment on non-linear complexity measures of autonomic regulation. From 46 patients with schizophrenia (acute non-mediated, G1, medicated, G2) and 23 matched (age, gender) healthy control subjects (CON) heart rate variability (HRV) in Time-and Frequency domain (TD, FD), Symbolic Dynamics (SD), Compression Entropy (CE), Detrended fluctuation analysis (DFA) and Poincare plot analysis (PPA) were analyzed. The results show that G1 differ significantly from CON (p<0.05) in linear and non-linear complexity measures. A considerably increase in the significance level (p<0.0001) was found in the medicated state comparing G2 with CON. These results show that schizophrenic patients have an autonomic dysregulation as shown by a significant increase of heart rate as well as reduced linear-and non-linear complexity measures and that treatment with antipsychotics result in a further altered autonomic regulation in schizophrenia patients.