>>12429763>What evolutionary benefit does depression give?Inwards reflection and a drive to return to a familiar place. Whenever children, even up to teenagers, get upset they always return to their room because it is a place of familiarity. When adults become depressed the want to return to a familiar place or time, usually from their youth.
Animals live simpler lives, their depression is usually driven by resource scarcity. This inwards reflection allows them to remember times and places where resources are bountiful. In more social animals depression is co-opted to prevent social groups from falling apart, elicit pity and facilitate sharing.
