Why Do People Move From Extreme Drug Abuse to Fanatical Religion? I’m Looking for a Psychological Pattern.

Though I respect the role of religion in recovery, I am worried about my friend’s new and extreme evangelical Christianity. He was heavily addicted to meth, went into a year long rehab in an evangelical Christian center, and has never been the same. When he got out, he spoke much of Christ. That was fine, since he found a guiding light, if you will. But he went back into the drugs. Now he’s been off of them again for a month. He’s broken up with the mother of his child, is convinced she’s possessed by demons, see’s thing in zealous and fanatical terms…I worry that he’s suffered permanent damage from the drug. He attributes certain psychological states to receiving the Holy Spirit (not that I don’t think that such experiences are unreal; rather, I think his is a sign of some extreme chemical imbalances).

Please, I’m not looking for any lecture on the way of God. I’m looking for some clues from someone with psychological knowledge who can point me in a direction to researc