I was very addicted to World of Warcraft a long time ago (a year is an incredibly long time for me, and I'm talking about OVER a year. What??? OVer A YeaR????). I think I played it incessantly in my spare time, stopped exercising, and eventually lost typical motor functions. Don't get me started what was left of my social skills.
When I dropped dinner on the kitchen floor because I couldn't carry a pan of food 10 feet I knew I had to stop cold turkey. And I did for some 7-8 months.
I still play today, but I've made sure that the game is much lower in my priorities. I play it every day, but if something, anything came up, the game gets turned off.