Catatonia is a cluster of motor features that appears in many recognized psychiatric illnesses. The classic signs are mutism, a rigid posture, fixed staring, stereotypic movements, and stupor. Catatonia was initially described in the first half of the 19th Century, but its name and our ideas about it are credited to the German psychopathologist Karl Ludwig Kahlbaum. In psychiatric disease classifications (such as the American Psychiatric Association's Diagnostic Statistical Manual and the World Health Organization's International Classification of Diseases), catatonia is traditionally linked to schizophrenia (American Psychiatric Association, 1952, 1980, 1987, 1994; World Health Organization, 1992). Today, however, we recognize that catatonia consists of identifiable and quantifiable motor signs that are part of a broad psychopathology that includes most of the major diagnostic classes.