I agree with this, but I would also add that fellowship is a HUGE part of dealing with sin issues. Most of the addicts that I have talked with are incarcerated, and they go back to the same group of friends, and perpetuate their activities. The two successful ones I've met, as soon as they left incarceration, got involved in Celebrate Recovery and actually are leading discussions within their groups.
I believe that having a tight group of Christian friends is important, because sin thrives in isolation.
You probably would agree but I just wanted to add that. I don't think unbelievers have much to add to believers, though, not when there's something better like Celebrate Recovery.
By the way, Celebrate Recovery can be great or it can be horrible. It depends on how a particular church implements it, and how sound their theology is.