Games which model downward spirals?

I’m interested in tabletop roleplaying games that have mechanics (ideally major mechanics) which model corruption, descent, disassociation, addiction, social withdrawal, and/or oblivion.

I’m not looking for something like a “roll versus insanity” madness system. Rather, I’m hoping for something more gradual and subtle—a steady loss of self via social, mental, or physical disintegration.

These are some fairly extreme/edgy words, but I’m not looking for misery porn. I’d prefer something which handles these topics with respect (or ideally, grace). I’m curious how different designers and different games have used mechanical frameworks to present the narrative of a downward spiral.