Religious practice can be remarkably effective at curing afflictions of the mind including depression and addiction. I knew a guy who recounted his story of being continuously depressed, addicted to everything he could get his hands on. One day he, on a whim, walked into a church, and was instantly cured of everything. Now he can hold a job, work towards a future. Doesn't go to AA meetings, doesn't need to. It's like God flipped a switch in his brain, is the way he described it. You'd think a guy like that would be preaching God from the rooftops, but he doesn't. He's real chill, easygoing.
I have met several people addicted to religion. It's socially accepted and can fill the needs of some people vary well, but it can also be just as destructive as heroin.