In an unusual twist on playing God, psychologist Milton Rokeach took three psychiatric patients who each believed himself to be Jesus Christ, the one true son of the Father, and had them live together for two years in the 1950s. As neuropsychologist Vaughan Bell explains in Slate, Rokeach — somewhat unethically — had the men argue, fight, and correspond with fake wives and hospital chiefs, to see if any of them would see their madness. Rokeach's book, The Three Christs of Ypsilanti, reveals that it wasn't just the Jesuses who were a little mad. Here's an excerpt of Bell's article:

"[The three men's] early meetings were stormy. 'You oughta worship me, I'll tell you that!' one of the Christs yelled. 'I will not worship you! You're a creature! You better live your own life and wake up to the facts!' another snapped back. 'No two men are Jesus Christs. … I am the Good Lord!' the third interjected, barely concealing his anger....

"Frustrated by psychology's focus on what he considered to be peripheral beliefs, like political opinions and social attitudes, Rokeach wanted to probe the limits of identity. He had been intrigued by stories of Secret Service agents who felt they had lost contact with their original identities, and wondered if a man's sense of self might be challenged in a controlled setting. Unusually for a psychologist, he found his answer in the Bible. There is only one Son of God, says the good book, so anyone who believed himself to be Jesus would suffer a psychological affront by the very existence of another like him."

Read the entire article in Slate.