I think that Dany will go (kind of ) crazy in the books, like she does in the show, but it'll be "helped" by some person, like Melisandre "helping" Stannis. For example, by the red priestess we saw for about one episode that disappeared right after. It (kind of ) makes sense, because Dany is somewhere in Essos (I think) , and the Red god is also worshiped in Essos, and in the show we see that the red priestess thinks that Dany is Azor Ahai, so she might make her burn people and stuff, like Melisandre did with Stannis. Also, Dany's family's words were “blood and fire”, and the priestesses both use blood magic(shown by Melisandre) and they burn people(so kindly shown by Melisandre again). And Dany happens to have three human eating, fire-breathing dragons.