The whole point in 90 in 90 is that you immerse yourself in NA which gives you a goal and also means that you will hear a load of shares, read a load of literature which will hopefully then inspire you to get a sponsor and work the steps which us the solution in NA.
It has been posted that if you just go to meetings NA doesn't claim to work for everyone but if you actually go and work the steps that claims to rarely fail as written in the NA Big Book.
Just to clarify once more if you want to recover from your addictions go to NA, get a sponsor who has worked the steps and recovered themselves, do the work, and hey presto no more addiction. I managed to get all this done in first 4 months. Good luck:-)