• The syndrome of multiple (dissociated) personality fell into disrepute around 1910. This has been attributed to loss of interest in hypnosis; psychiatrists believed the syndrome resulted from hypnosis and that they were being duped. However, around 1910 an important event occurred in psychiatry: Bleuler introduced the term "schizophrenia" to replace "dementia praecox." This factor also played a role in the decline of recognition of the multiple personality syndrome, and many of these cases were diagnosed as schizophrenia. A review of IndexMedicus from 1903 through 1978 shows a dramatic decline in the number of reports of multiple personality after the diagnosis of schizophrenia "caught on," especially in the United States. A review of clinical reports indicates that many patients with multiple personality had been diagnosed and treated as schizophrenics.
Rosenbaum M. The Role of the Term Schizophrenia in the Decline of Diagnoses of Multiple Personality. Arch Gen Psychiatry. 1980;37(12):1383-1385. doi:10.1001/archpsyc.1980.01780250069008