It appears that extreme religious delusion poses some threat to the sanity of the human mind.
Those who are no longer with religion say that they still have flashbacks to believing in "god", even sometimes talking to "him" when they are lonely, even praying in some sort. I myself no longer do this but the idea of god still drifts to me sometimes... I was with religion for 12 years of my life, it's very difficult to get those ideas out of my mind.
I'm guessing religion possibly has a (likely permanent) negative effect on the human brain, depending on how long the believer stays with the religion.
If you look at folks who are still deeply deluded with religion, they appear to be in some other kind of state than we are, almost as if they aren't entirely sure of what they are saying. It's very strange. In this case, I'm guessing religion does the job it was intended to do - to turn people in tho sheepish followers who do not dare question the validity of their beliefs.