Although catatonia has traditionally been thought of as a type of
schizophrenia, the author presents studies indicating that catatonia may be
at least as common in bipolar disorder as it is in schizophrenia. He points
out that changing definitions of schizophrenia and affective disorder
require a reassessment of catatonia and its incorporation in modern
diagnostic systems. The discussion represents material presented at the
Affective Disorders Advisory Committee of the American Psychiatric
Association Work Group to Revise DSM-III.