Postictal psychosis: Evidence for extrafocal functional precursors.

BACKGROUND: Postictal psychosis is a particular entity with unclear relationship to preceding epileptic seizures. In particular, the role of ongoing interictal and ictal epileptic discharges in the epileptic focus, as opposed to widespread changes in cortical networks in its generation, has remained controversial.

METHODS: We describe two patients with temporal lobe epilepsy who developed a schizophreniform postictal psychosis after seizure clustering during or following invasive depth EEG monitoring. EEGs were analyzed for the presence of interictal and ictal discharges, and videos were analyzed for possible precursors of postictal psychosis, with particular focus on postictal neuropsychological impairments in preceding episodes.

RESULTS: The development of psychosis was related neither to ongoing subclinical ictal activity nor to suppression of interictal discharges in the epileptic focus. There was, however, increasing severity and duration of cognitive impairment following the seizures in the cluster preceding psychotic symptoms in that the patients progressively developed postictal aphasic symptoms and disorientation before becoming overtly psychotic.

CONCLUSION: The cases suggest that the buildup to schizophreniform postictal psychosis may not be related to epileptic discharges in the focus, but may develop as a consequence of ictal activity and postictal functional impairment of extended brain regions.