A 42-year-old Japanese woman with a 10-year history of schizophrenia was admitted due to a disturbance in consciousness that met the diagnostic criteria for both neuroleptic malignant syndrome (NMS) and malignant catatonia. Despite systemic supportive treatments, the catatonic symptoms preceding autonomic symptoms persisted. The symptoms improved after lorazepam administration, leading to a retrospective diagnosis of malignant catatonia. Catatonia is thought to be caused by a dysfunction of ganmma-aminobutyric acid type A receptors in the cortico-cortical networks of the frontal lobes, which causes hypoactivity of the dopaminergic transmission in the subcortical areas. Identifying the catatonic symptoms preceding autonomic symptoms could aid in distinguishing malignant catatonia from NMS.