Psychosis and peri-ictal confusional states.

The relationship of epilepsy with psychosis is intriguing to neurologists and psychiatrists alike. This review highlights these relationships, including (a) interictal psychosis, in which the presence of psychotic episodes is not temporally related to the occurrence of seizures, (b) postictal psychosis, characterized by an increased number of seizures followed by a period of lucidity and subsequent psychotic symptoms, and (c) ictal psychosis, in which psychotic symptoms occur in association with ictal discharges on EEG. Also discussed are other kinds of episodic symptoms that may mimic psychosis, including nonconvulsive status epilepticus, postictal delirium, and peri-ictal aggressive behavior. The controversial concept of "forced normalization," which proposes an antagonistic relationship between seizures and psychosis, is also explored. Finally, the potential contribution of antiepileptic drugs to psychotic symptomatology and the effects of antipsychotic agents on seizure threshold are examined.