A 21-year-old female presented excitement, auditory hallucination, monologue, and insomnia. After 1 week of risperidone administration, she showed hyperthermia, salivation, and muscle rigidity. Risperidone was discontinued, but stupor, convulsions, and respiratory distress developed. In the intensive care unit where she was transferred, catatonic symptoms such as stupor or excitement, catalepsy, and negativism were prominent. In addition, severe bronchorrhea causing respiratory failure was observed. Her catatonic symptoms, hyperthermia, and bronchorrhea resolved by ECT. After recovery, affective flattening, alogia, and avolition remained. The final diagnosis was MC associated with schizophrenia. This report suggests that MC may be complicated by severe bronchorrhea, but this condition responds to ECT.