Intensive monitoring of interictal psychosis in epilepsy.

Ten epileptic patients developed interictal psychosis while being treated in hospital for seizure control. They were subjected to intensive behavioral, video-electroencephalographic, and serum anticonvulsant monitoring for an average of 7.1 weeks in a specialized epilepsy unit. In 9 patients, the interictal psychosis was indistinguishable from acute schizophrenia. Only 5 of these patients had complex partial seizures; the other 4 showed evidence of generalized epilepsies. Thus a "unique" association between schizophreniform psychosis and complex partial seizures, noted by previous authors, could not be confirmed. Only 1 patient showed normalization of the electroencephalogram during psychosis and an inverse relationship between psychosis and seizure frequency. In most cases the emergence of psychosis could not be explained. Interictal psychosis in epilepsy appears to be a spectrum of disorders that may be multifactorially determined.