Swedenborg was similar in some ways, like his claimed meetings with so many principle persons in the Bible: http://peacebyjesus.witnesstoday.org/Swedenborg.html
I have a family member who suffers from delusions of grandeur, paranoid schizophrenia and other mental health problems. He is and has been convinced for years that he is Elijah the prophet and that he will replace "God the Father Almighty" and be the new god. He said "people" have told him this through a "transceiver" implanted in his brain as well as the "voices" he hears. There is nothing I can say that helps him. When I show him in Scripture what the Bible says about Elijah and Almighty God, his response is, "You can't believe everything you read in the Bible.". I don't see whole lot of difference between him and some of these self-proclaimed prophets and saviors. It's just like Jesus warned us - MANY would come in his name and try to deceive people away from the truth. Some of it is because of pure evil from the Devil and some are just people seriously mentally ill who really believe what they say. Thank God we have the Scriptures to lead and guide us! Those who ignore the Bible are sometimes sitting ducks for the craziness out there.