There was an experiment where three schizophrenic men who believed they were Jesus Christ were all put in one place to sort it out.
The Three Christs of Ypsilanti
The Three Christs of Ypsilanti (1964) is a book-length psychiatric case study by Milton Rokeach, concerning his experiment on a group of three paranoid schizophrenic patients at Ypsilanti State Hospital in Ypsilanti, Michigan. The book details the interactions of the three patients, Clyde Benson, Joseph Cassel, and Leon Gabor, who each believed himself to be Jesus Christ.
“To study the basis for delusional belief systems, Rokeach brought together three men who each claimed to be Jesus Christ and confronted them with one another’s conflicting claims, while encouraging them to interact personally as a support group. Rokeach also attempted to manipulate other aspects of their delusions by inventing messages from imaginary characters. He did not, as he had hoped, provoke any lessening of the patients’ delusions, but did document a number of changes in their beliefs.
While initially the three patients quarreled over who was holier and reached the point of physical altercation, they eventually each explained away the other two as being mental patients in a hospital, or dead and being operated by machines”
The Three Christs of Ypsilanti was first published in 1964. Rokeach came to think that his research had been manipulative and unethical, and he offered an apology in the afterword of the 1984 edition of the book: “I really had no right, even in the name of science, to play God and interfere round the clock with their daily lives.” The book was re-published by New York Review of Books in 2011.