Special features of autonomic regulation in patients with seasonal depressions

Parameters of histograms distribution of ECC R-R intervals (the mode, mode amplitude, variation range) were compared in 60 healthy individuals and 45 patients with seasonal depressions. These ECC 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 o f depressive symptomatology the parameters of histograms in terms of R-R di stribution were changed in comparison with the healthy individuals: mode wa s displaced to the region of the short intervals, the mode amplitude was in creased and the variation range was reduced. All these data indicate increa se 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 cou rse of pharmacotherapy the dynamics of these parameters was less marked in patients with fall-winter depressions than in cases of spring-summer depres sions.