Here are quotes from the (in)famous Richard Dawkins's book. It's title explains it all: do not believe in god.
I have only read the first few chapters but I already think he is full of himself; I won't befriend him (if there ever is a chance). I have also found no reason to disagree with what he says. This guy is controversial and amplifies his viewpoint in a planned, entertaining way – reminds me of Michael Moore – which always has a point. I might disagree with, but won't ignore, what he says.
As to whether it is a symptom of a psychiatric disorder, I am inclined to follow Robert M. Pirsig, author of Zen and the Art of Motorcycle Maintenance, when he said, 'When one person suffers from a delusion, it is called insanity. When many people suffer from a delusion it is called Religion.'