First, we would like to comment on the proposed categories for the diagnostic classification of catatonia. The category "delirious catatonia" is confusing, since it is difficult to distinguish catatonic excitement from the excited states of bipolar disorder. As a consequence, the category "delirious catatonia" shows an important overlap with the DSM category of the manic episode. An alternative classification could be composed of two categories, "nonmalignant catatonia" and "malignant catatonia," with an additional specifier of "retarded" or "excited." In this classification, the Kahlbaum syndrome would be regarded as a retarded form of nonmalignant catatonia, and delirious mania would be classified as an excited form of nonmalignant catatonia. The classic description of "lethal catatonia" would correspond with the excited malignant catatonia, whereas neuroleptic malignant syndrome could be considered a retarded variant.