To the Editor: Drs. Levin and Martin miss the point of our argument. We did not claim that catatonia is a delirious process but cited the DSM-IV-TR category of delirium (293.0) as an analogy for the location of catatonia. We could also have cited dementia (290.0) as our analogy.

We presented catatonia as a distinct syndrome that is identifiable by its psychopathology, occurs in a wide range of psychiatric disorders, and is responsive to defined interventions. We suggested that catatonia deserves a class of its own in psychiatric classifications, much as delirium and dementia are individually defined. We presented extensive evidence that catatonia is not limited to a subtype of schizophrenia (295.2) or secondary to a medical condition (293.89), as formulated in DSM-IV-TR.

Classifying catatonia as a distinct psychopathological entity encourages its diagnosis, application of its unique treatments, and its research study. The textbook formulation of catatonia based on the DSM classification is no longer useful in psychiatric practice.

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