• In 11 patients without histories of absence seizures, acute prolonged confusion and/or prominent psychiatric manifestations occurred between the ages of 42 and 76 years, and were accompanied by 1 to 2.5-Hz generalized spike-wave or multiple spike-wave discharges in the EEGs. The patients were successfully treated with intravenously administered diazepam followed by orally administered phenytoin sodium and/or phenobarbital. The ictal confusion in later life seems to be an entity distinct from the typical petit mal status of early onset.