Literature Review Supports Dropping Schizophrenia Subtypes

The traditional “subtypes” of schizophrenia—catatonic, disorganized, paranoid, residual, and undifferentiated—have been eliminated from criteria for the new DSM-5 to be published this month, a decision that appears to be supported by diminished use of the subtypes in literature on schizophrenia research. A review of literature over the last 20 years appearing in the May Schizophrenia Bulletin found that use of those subtypes has fallen markedly.

Researchers at the University of California, San Diego, and Maryland Psychiatric Research Center examined five psychiatry journals (Molecular Psychiatry, American Journal of Psychiatry, Archives of General Psychiatry, Schizophrenia Bulletin, and Biological Psychiatry) for the frequency with which DSM-ICD subtypes are used in reports from 1990 to 2010. They found that the proportion of reports using subtype designations decreased from 28.9 percent in 1990 to less than 10 percent in 2010. In an interview with Psychiatric News earlier this year, William Carpenter, M.D., chair of the DSM-5 Psychotic Disorders Work
Group and one of the investigators in the new study, said the subtypes were no longer clinically useful. “The main reason is that they have not proven useful clinically and are not a good heuristic for understanding psychosis,” Carpenter said. “It’s a mistake to think of catatonia as a subtype of schizophrenia, and the subtypes have tended to reinforce that mistake.”

The Schizophrenia Bulletin article can be read here. For more information on this subject, see Psychiatric News here.

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