• Evidence exists to support the concept of pathology or diseases of hypnosis. Multiple personalities is such a syndrome, as are many or perhaps all cases of hysteria (Briquet's syndrome). The crux of multiple personalities is the subject's unrecognized abuse of self-hypnosis, by which she creates personalities, beginning at age 4 to 6 years. The process of self-hypnosis allows the delegation of an experience or a function to an alter ego, henceforth relegated to unconsciousness by the amnesia of hypnosis. Most of these patients qualify for the diagnosis of hysteria (Briquet's syndrome), and many are diagnosed incorrectly as being schizophrenic because of their hallucinations, paranoid ideas, and "delusions." Hysteria may owe many of its characteristics to the self-hypnotic induction of conversion and other symptoms.
Eugene L. Bliss. Multiple PersonalitiesA Report of 14 Cases With Implications for Schizophrenia and Hysteria. Arch Gen Psychiatry. 1980;37(12):1388–1397. doi:10.1001/archpsyc.1980.01780250074009