This study reports the development of a severe life threatening catatonia in a 19 years old woman. Initially she displayed paranoia and hallucinations, which were complicated under neuroleptic treatment by extended rigor, temperature and autism. ECT led to a certain improvement of all symptoms, but complete recovery was only reached after neuroleptic drug withdrawal. The course of this case shows that the differential-diagnosis between genuine "pernicious" catatonia and the neuroleptica malignant syndrome is very difficult clinically. Therefore, before the application of ECT, an observation period without any neuroleptic drugs is recommended in similar cases with rigor, stupor and raised temperature, to avoid additional risks by narcosis and ECT itself. Diagnostic and therapeutic outlines are given.