Of the motor signs described by Kahlbaum, how many are useful in making the diagnosis of the catatonia syndrome? How often is the syndrome identified? In studies of incidence, researchers used the more prominent items of mutism, posturing, negativism, catalepsy, and stereotypy as criteria for catatonia. More recently, rating scales with more extensive lists of signs have been developed. In the search for a structure among the signs of catatonia, factor analytic studies have been done. Despite this experience with catatonia over the past few decades, its role in the DSM and ICD psychiatric classification systems remains restricted and problematic. In this chapter, we describe this experience and suggest modifications in classification systems.

DSM classification of catatonia

After Kahlbaum's 1874 description, many reports confirmed the presence of catatonia in patients with psychotic and mood disorders (see Chapter 1). In a decision that strongly influenced posterity, Kraepelin incorporated catatonia as a feature of dementia praecox. He described the onset as subacute, often beginning with a depressed mood.