Heart rate variability response to mental arithmetic stress is abnormal in first-degree relatives of individuals with schizophrenia

Background: Schizophrenia patients exhibit an abnormal autonomic response to mental stress. We sought to determine the cardiac autonomic response to mental arithmetic stress in their unaffected first-degree relatives. Methods: Heart rate variability (HRV) analysis was performed on recordings obtained before, during, and after a standard mental arithmetic task to induce mental stress. 22 unaffected first-degree relatives of patients meeting DSM-IV criteria for schizophrenia (R) and 22 healthy individuals (C) were included in this study. Results: Patients' relatives (R) had a normal response to the mental arithmetic stress test, showing an increased heart rate compared with controls. They also displayed the characteristic pattern of relative contributions of HRV components that consists of increased low-frequency (LF) HRV and decreased high-frequency (HF) HRV. Recovery of the resting pattern of HRV immediately after stress termination was observed in healthy subjects (LF 62 ± 16% vs. 74 ± 10%, HF 37 ± 16% vs. 25 ± 10%, F = 9.616, p = 0.004), but not in patients' relatives (LF 60 ± 19% vs. 70 ± 13%, HF 40 ± 19% vs. 29 ± 13%, F = 8.4, p = 0.056). Conclusions: First-degree relatives of schizophrenia patients exhibit an abnormal pattern of protracted response to mental arithmetic stress, though less intense than that observed in patients in a previous study. This suggests that a pattern of autonomic response to stress may therefore be familial and heritable.Fil: Castro, Mariana Nair. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vigo, Daniel Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; ArgentinaFil: Chu, Elvina. University College London; Estados UnidosFil: Fahrer, Rodolfo D.. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: de Achával, Delfina. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Costanzo, Elsa Y.. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Leiguarda, Ramón Carlos. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Nogués, Martín. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; ArgentinaFil: Cardinali, Daniel Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas; ArgentinaFil: Guinjoan, Salvador Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia; Argentin

Heart rate variability response to mental arithmetic stress in patients with schizophrenia Autonomic response to stress in schizophrenia

Abstract Background: The vulnerability-stress hypothesis is an established model of schizophrenia symptom formation. We sought to characterise the pattern of the cardiac autonomic response to mental arithmetic stress in patients with stable schizophrenia. Methods: We performed heart rate variability (HRV) analysis on recordings obtained before, during, and after a standard test of autonomic function involving mental stress in 25 patients with DSM-IV schizophrenia (S) and 25 healthy individuals (C). Results: Patients with schizophrenia had a normal response to the mental arithmetic stress test. Relative contributions of lowfrequency (LF) HRV and high-frequency (HF) HRV influences on heart rate in patients were similar to controls both at rest (LF 64 ± 19% (S) vs. 56 ± 16% (C); HF 36 ± 19% (S) vs. 44 ± 16% (C), t = 1.52, p = 0.136) and during mental stress, with increased LF (S: 76 ± 12%, C: 74 ± 11%) and decreased HF (S: 24 ± 12%, C: 26 ± 11%) in the latter study condition. Whilst healthy persons recovered the resting pattern of HRV immediately after stress termination (LF 60 ± 15%, HF 40 ± 15%, F = 18.5, p b 0.001), in patients HRV remained unchanged throughout the observed recovery period, with larger LF (71 ± 17%) and lower HF (29 ± 17%) compared with baseline (F = 7.3, p = 0.013). Conclusions: Patients with schizophrenia exhibit a normal response to the mental arithmetic stress test as a standard test of autonomic function but in contrast with healthy individuals, they maintain stress-related changes of cardiac autonomic function beyond stimulus cessation