From The New York Times:
Angelo, a London-born scientist in his early 30s with sandy brown hair, round wire-frame glasses and a slight, unobtrusive stammer, vividly recalls the day he began to hear voices. It was Jan. 7, 2001, and he had recently passed his Ph.D. oral exams in chemistry at an American university, where, for the previous four and a half years, he conducted research into infrared electromagnetism. Angelo was walking home from the laboratory when, all of a sudden, he heard two voices in his head. “It was like hearing thoughts in my mind that were not mine,” he explained recently. “They identified themselves as Andrew and Oliver, two angels. In my mind’s eye, I could see an image of a bald, middle-aged man dressed in white against a white background. This, I was told, was Oliver.” What the angels said, to Angelo’s horror, was that in the coming days, he would die of a brain hemorrhage. Terrified, Angelo hurried home and locked himself into his apartment. For three long days he waited out his fate, at which time his supervisor drove him to a local hospital, where Angelo was admitted to the psychiatric ward. It was his first time under psychiatric care. He had never heard voices before. His diagnosis was schizophrenia with depressive overtones.
For more than a half-century, auditory hallucinations have primarily been studied and discussed in terms of severe mental illness, most notably schizophrenia, and linked to bizarre delusions, disordered thought and emotional dissociation. Approximately 75 percent of patients diagnosed with schizophrenia hear voices, and for the majority the experience is overwhelmingly negative.
More here.