There's a quote I like which I heard from Norman Finklestein which he claims to attribute to himself, it's "for what is depression, but life stripped of its illusions". Perhaps when the instincts of optimism are stripped away, our nervous system, our brains react accordingly to the danger or fate. What's more appropriate for the evil nature of life but the rotting, horror inducing feeling of depression and anxiety?
Is it perhaps that the depressed are the normal people giving a normal reaction to life? Maybe then, it's just a cope. Anyways, take care of yourself