Jerry Coyne took a look at a hypothesis that depression is an evolutionary adaptation.
in two new papers by Andrews and Thompson. In short, their “analytical rumination hypothesis” (ARH) proposes that the “malady” we call depression is actually an adaptive behavior built into our ancestors by natural selection. When facing difficult social problems, selection is said to have promoted behaviors that make individuals withdraw from life, ceasing to engage in formerly pleasurable activities like socializing, eating, and sex. This is all in the service of rumination: freed from other activities and commitments, the depressed individual is said to analyze the problems that led to depression in the first place, eventually solving them and re-entering society. This is “adaptive” because individuals