I don’t know that a person with a high IQ is any more (or less) likely to suffer the mental disorders listed above than a person of average or low IQ (and, BTW, rumination syndrome is a physical disorder, not a mental one). But that’s beside the point. Classifying “the god delusion” as “[an]other mental disorder” is a classic example of petitio principii (begging the question). So, as regards the first paragraph above: kudos for the rhetoric, but no prizes for the logic (since there isn’t any).
The second paragraph is more interesting, because the quote from Dawkins reveals a characteristic flaw in his argumentation: the failure to distinguish religious faith from fideism. The consequence of this failure is that the “unquestioning faith” he attacks is largely a straw man of his own imagining (at least as far as mainstream Christianity is concerned).
On the role faith plays in Christianity, a good place to start would be the essay “On Obstinacy in Belief” by C. S. Lewis.