Lethal catatonia, a life-threatening, febrile neuropsychiatric disorder, was reported before the introduction of modern psychopharmacologic treatment. Kraepelin (1) discussed this disorder as a syndrome that comprises a characteristic cluster of symptoms, such as catalepsy, negativism, posturing, muscular rigidity, and verbigeration. In order to assess the current status of lethal catatonia, Mann et al. (2) identified a series of 292 cases reported since 1960.The recognition that lethal catatonia is a well-defined neuropsychiatric syndrome that occurs during the course of both organic and functional psychiatric illnesses has major clinical implications (3).Electroconvulsive therapy is the treatment of choice for lethal catatonia. Dantrolene sodium therapy presents an important advance in the therapy of sometimes life-threatening hypercatabolic disorders associated with muscle spasticity (4, 5).We report a case of apparent lethal catatonia in a 39-yr-old male psychiatric patient with a hypercatabolic disorder accompanied by muscle spasticity.