We present a patient with topiramate-induced psychosis who developed alternative psychosis following temporal lobectomy. The number of surgical candidates for temporal lobectomy is increasing as is the frequency of psychiatric co-morbidities. Preoperative planning should take account of these psychiatric co-morbidities. In particular, precautions should be taken when antiepileptic drug-induced psychosis occurs, as this could predict the occurrence of alternative psychosis following lobectomy.