Epileptic psychoses and anticonvulsant drug treatment.

Forty four consecutive patients with epilepsy and psychoses were studied retrospectively for psychotic episodes associated with changes in antiepileptic drug therapy. Twenty seven patients (61%) developed their first episode of psychosis unrelated to changes in their antiepileptic drug regimen. Twenty three of these patients developed psychoses with temporally unrelated changes in seizure frequency. Many patients had chronic schizophrenia-like psychotic symptoms. Seventeen patients (39%) developed their first episode of psychosis in association with changes in their antiepileptic drug regimen. Twelve patients developed psychoses temporally related to seizure attenuation or aggravation. Many of their psychotic symptoms were polymorphic with a single episode or recurrent episodes. No marked differences were found in the various clinical backgrounds between the two groups. In the drug-related group, seven patients developed psychoses after starting add-on therapy with a new antiepileptic drug, six after abruptly discontinuing their drugs, and four after taking an overdose of antiepileptic drugs. Based on the present findings, drug regimens should be changed gradually and compliance should be maintained to prevent epileptic psychoses.