[Special features of autonomic regulation in patients with seasonal depression]

Parameters of histograms distribution of ECG R-R intervals (the mode, mode amplitude, variation range) were compared in 60 healthy individuals and 45 patients with seasonal depressions. These ECG parameters reflect influence of sympathetic and parasympathetic parts of the autonomic nervous system on the rhythms of cardiac contractions. In the period of active development of depressive symptomatology the parameters of histograms in terms of R-R distribution were changed in comparison with the healthy individuals: mode was displaced to the region of the short intervals, the mode amplitude was increased and the variation range was reduced. All these data indicate increase of the sympathetic activity and reduction of parasympathetic activity as compared with the control individuals. In the patients with spring-summer depressions the determined parameters of autonomic nervous system were more changed than in the patients with autumn-winter depressions. Under the course of pharmacotherapy the dynamics of these parameters was less marked in patients with fall-winter depressions than in cases of spring-summer depressions.