A Circadian Signal of Change of Season in Patients With Seasonal Affective Disorder

Abstract

The results show that patients with seasonal affective disorder generate a biological signal of change of season that is absent in healthy volunteers and that is similar to the signal that mammals use to regulate seasonal changes in their behavior. While not proving causality, this finding is consistent with the hypothesis that neural circuits that mediate the effects of seasonal changes in day length on mammalian behavior mediate effects of season and light treatment on seasonal affective disorder.