There is a point where a committed believer becomes so caught up in their religious narrative that they seem to be under a spell and incapable of functioning in the "reality-based community." The great majority of believers thrive in the real world, where religious belief is encouraged, and it often helps in every facet of life. But beyond that point where the young zealot and older convert often tread lies madness, albeit a (hopefully) temporary state.
I crossed into that abyss a few times as a believer, but luckily I got back out each time. That place does play a sweet siren's call to a doctrinaire's ears, promising a full surrender to one's fantasies of belief. But it is a dreadful hallucination, inviting the organically healthy into the schizoid's dream. Isolated, it can be a refuge for the believer, but once foisted on another, the believer either is revealed his folly, or not, and for the latter case, it presents just as psychosis.
Beware taking your faith too seriously.