The authors review catatonia, especially malignant catatonia, suggest a revised nomenclature, and establish a basis for furthering our understanding and treatment of this syndrome. After a brief historical review of catatonia, they review all available recent (1986-1991) English-language reports on malignant catatonia and summarize 5 cases of psychiatric malignant catatonia seen at their institution. Although much has been written about malignant catatonia "due to neuroleptics," malignant catatonia caused by other factors has received less attention, hindering our ability to recognize and treat non-neuroleptic-induced malignant catatonia. Catatonia, including malignant catatonia, occurs infrequently, but recognition and management are essential with a syndrome that can be life-threatening.