Catatonia is a syndrome of specific motor abnormalities closely associated with disorders in mood, affect, thought, and cognition. The principal signs of the disorder are mutism, immobility, negativism, posturing, stereotypy, and echophenomena. Dysfunctions in other motor actions have also been suggested as within the syndrome of catatonia, but the principal signs are defined in Table 2.1.

Mutism and stupor are principal catatonic signs but neither alone is pathognomonic. Other motor behaviors should be present, and most patients with one sign exhibit four or more catatonic features. Because the number of features required for the diagnosis is not experimentally established, we consider two of the classic catatonia signs as sufficient to meet criteria for the syndrome. (In Table 5.1, we offer our diagnostic criteria for catatonia.)

There is also a lack of consensus about the duration of the behaviors necessary to make the diagnosis. In some patients, the signs are unstable or transient, while in others, they are present for days, weeks, or months. Writers in the 19th and early 20th centuries described patients in whom catatonia persisted for years. Some clinicians accept the presence of signs for one hour as adequate for its identification, while others hold persistence for a day as necessary. We identify catatonia when features are present for an hour or longer or are reproducible on two or more occasions.