Because of its N-methyl-d-aspartic acid antagonist properties, amantadine (100–500   mg three times a day), and its derivative memantine (5–20   mg/day), have been tried in catatonia. Carroll and coworkers identified 25 cases of amantadine and memantine use in the treatment of catatonia. All cases improved, mostly after 1–7   days. It should be noted, however, that six were unpublished, and that seven other were cases experiencing a “catatonia-parkinsonian syndrome” while under treatment with the high-potency neuroleptic drugs haloperidol or fluphenazine. The symptoms diminished when neuroleptics were tapered, and they added amantadine. Since then, they have published eleven additional cases describing the successful use of amantadine or memantine in catatonia. In one case, in an adolescent girl, catatonia that was resistant to ECT improved after the addition of amantadine. Only in a review of Hawkins and coworkers, they report a case in which the use of amantadine remained without eff