To the Editor: The protracted course of catatonia in a 16-year-old boy was recently described in the March issue of the Journal as an example of anti-NMDA (N-methyl-d-aspartic acid) receptor encephalitis (1). The patient exhibited stupor, psychomotor retardation, mutism, posturing, stereotypical movements, refusal to eat and drink, and episodic agitation. These signs meet the criteria for catatonia, classified in DSM-IV-TR as catatonic disorder due to a general medical condition (293.89). No clear medical or toxic cause was found, nor were any of the prescribed psychotropic medications or immune therapies, including steroids, intravenous immune globulin, and rituximab, beneficial. After treatment with haloperidol and other antipsychotics, the symptoms worsened. The syndrome slowly abated, and the patient returned to baseline function 7 months after the onset of symptoms.