Linear and nonlinear analysis of autonomic regulation in depressed patients

To investigate the effect of depression and medication on the autonomic nervous system (ANS) we compared 25 patients suffering from depression with 72 matched control subjects (CON). From every patient three times ECG and non-invasive blood pressure were recorded in: acute non-mediated state (T1), medicated state (T2) and clinical recovered state (T3). Cardiac autonomic regulation was evaluated by linear and nonlinear analysis methods. The results show that non-medicated depressed patients differ significantly from CON (p<0.05). In the medicated state considerably high significant differences between depressed patient and CON were found (p<0.0001). After an 18 months follow-up a normalization of autonomic parameters was achieved in depressed patients. These results show that depression influences autonomic parameters significantly and that medical treated clinical recovered patients approximate to healthy controls in autonomic regulation.