Autonomic modulation in healthy first-degree relatives of patients with major depressive disorder

Background: Cardiac mortality is known to be increased in patients with major depression. Several studies have reported an imbalance within the autonomic nervous system (ANS) of patients with major depressive disorder (MDD) as one putative cause. Since a heritability of autonomic modulation was demonstrated in healthy subjects, we aimed to investigate autonomic modulation in first-degree relatives of patients with MDD to find potential autonomic imbalances. Methods: We included 30 patients with MDD, 30 of their first-degree relatives (siblings or offspring) and 30 matched healthy controls in our study. We obtained a high resolution electrocardiogram and beat to beat blood pressure measurements for 30 min at rest Linear and nonlinear parameters of heart rate variability (HRV) and baroreflex sensitivity (BRS) were calculated. Results: Parameters of HRV and BRS did not differ significantly between relatives and controls. We found significant differences between patients and controls for some HRV and BRS parameters confirming results of previous studies. Discussion: Findings of our study suggest that an imbalance of autonomic function is related to patients with depression and not to first-degree relatives. Thus, a genetic background for autonomic dysfunction is rather unlikely. (C) 2011 Elsevier Inc. All rights reserved.