MAJOR DEPRESSION AND CARDIAC AUTONOMIC CONTROL

We investigated autonomic control of heart rate in patients with major depression, melancholic type. Twenty-three depressed inpatients who w ere being treated with tricyclic antidepressants and 23 depressed pati ents who were taking no medications were compared with age- and sex-ma tched control groups on resting cardiac vagal tone and heart rate, In unmedicated depressed patients, cardiac vagal tone was comparable to t hat of control subjects, but heart rate was significantly higher, This increase in heart rate may have been due to sympathetic activation ca used by anxiety, since the depressed patients were significantly more anxious than the control subjects, Medicated patients exhibited dimini shed cardiac vagal tone and higher heart rate than unmedicated patient s and controls. This was probably due to the anticholinergic effects o f the antidepressants, Our findings suggest that cardiac vagal tone is not lower than normal in patients with depression, melancholic type. (C) 1997 Society of Biological Psychiatry.