Edit, from TFA: "“This decrease results from a plurality of factors, such as the positive impact of the graduated response procedure, the transformation of practices regarding the consumption of cultural works on the internet, the acceleration of the dissemination of legal offers during the year, or even increasing use of workaround solutions (VPNs) by Internet users,” the regulator explains."

To that end, my harebrained idea is to put a hard cap on the number of members a subreddit can have, and restrict posting and voting to those members. If people want, they can create <subreddit>2 and so on, each cluster self-regulating. To prevent squatting, you can only spawn a new one once the last one reaches a critical mass, and it has to be started by a member of the old one.

Based solely on this paragraph, you sound like me, so I'm going to take a shot and tell you what I'd tell my 24 year old self: no amount of browbeating yourself is going to fix this. Discipline takes work, yes, but it also takes a mind able to do the work. See a therapist, and/or a doctor. Lay all this stuff out and see what they say. After that, start small. But not just small--something you'd think you would enjoy. Don't force yourself to eat your vegetables at this stage. Something that lands in the middle of fun and enriching, which can produce a skill or a product you will eventually be proud of, but which in the meantime you like doing.

Take heart. This is doable. I've been there, it sucks, and there's a way out.