Psychosis after resection of ganglioglioma or DNET: Evidence for an association

Purpose: David Taylor and Murray Falconer suggested that some patients may develop a psychotic illness after resection of a ganglioglioma that led to intractable seizures. They implied that the mechanism of this association r emained unclear. This concept is currently not universally accepted (M. Tri mble, personal communication). Methods: We studied six children or young adults from four centers who deve loped psychosis after resection of a ganglioglioma or dysembryoplastic neur oepithelioma (DNET). Results: All patients were operated on because of intractable epilepsy. The lesions involved mainly the temporal lobe. Patients had good outcomes for seizure control. In none of the six was potentially psychogenic medication used nor were the psychotic symptoms postictal in nature. The psychosis was schizophreniform with paranoid features and prominent depressive symptoms. Although some behavioral abnormalities were described preoperatively, none had been psychotic before operation. This type of psychotic reaction was n ot encountered in the four centers in a comparable period after resection o f other types of lesions. This complication is rare; it occurred in only on e of 39 patients who had such a lesion resected. Conclusions: Psychotic illness may rarely occur after resection of a gangli oglioma or DNET for treatment of intractable epilepsy. This does not seem t o occur after removal of other types of lesions. Because the patients had g ood outcomes for seizures, the mechanism may be related to "forced normaliz ation." The original observations of Taylor and Falconer are confirmed by t his study; the reasons for the selective occurrence, however, remain specul ative.