The Evolution of Depressive Phenotypes

Depression is a heterogeneous collection of phenotypes sharing partially overlapping genes, neurobiology, and symptoms. This chapter applies an evolutionary perspective to the distinct etiologies and functions of three reliably identified depressive phenotypes: sickness behavior, starvation depression, and melancholia (i.e., depression with melancholic features). Infection and food shortage are evolutionarily ancient problems, and so sickness …