The chronobiology and neurobiology of winter seasonal affective disorder

Figures & data

Figure 1. Schematic model of the biology of seasonal affective disorder (SAD). SAD is depicted as a complex phenotype shaped by multiple vulnerability factors acting at the level of biological rhythms, mood and appetite regulation, light sensitivity etc. Each of these intermediate phenotypes is in turn shaped by multiple genes. As with other complex phenotypes, it is unlikely that a single vulnerability factor or gene can account for SAD - rather it is the interaction of multiple factors interacting with the environment that shapes the ultimate phenotype.