Major depression is associated with cardiac autonomic dysregulation

Objective: Altered cardiac autonomic function has been proposed in patients with major depression (MD), but the results are mixed. Therefore, analyses with larger sample sizes and better methodology are needed. Methods: To examine whether cardiac autonomic dysfunction is associated with MD, 498 unmedicated patients with MD and 462 healthy volunteers, aged 18-65 years, were recruited for a case-control analysis. We used the Hamilton Depression Rating Scale (HAM-D) and the Beck Depression Inventory (BDI) to assess depression severity. Cardiac autonomic function was evaluated by measuring heart rate variability (HRV) parameters. Frequency-domain indices of HRV were obtained. Results: Patients with MD exhibited reduced cardiac vagal control compared to healthy volunteers, and depression severity was negatively correlated with cardiac vagal control. Stratified analyses by suicide ideation revealed more pronounced cardiac vagal withdrawal among MD patients with suicide ideation. Conclusion: This study shows that MD is associated with cardiac autonomic dysregulation, highlighting the importance of assessing HRV in currently depressed patients, given the higher risk for cardiac complications in these individuals. Taking into account that suicidal depressed patients had more adverse patterns of HRV, one might consider the treatment to restore the autonomic function for the patient population having increased susceptibility to autonomic dysregulation.