Familial photosensitive epilepsy: effectiveness of clonazepam.

We describe the clinical features of a family with photosensitive epilepsy, followed for 13 years. Generalized paroxysmal discharges induced by photic stimulation appeared in all 9 siblings. Generalized seizures, myoclonic jerks, and absences appeared in variable combination in 7 of them who on clonazepam remained free from seizures for a seven-year follow-up period. On EEG the paroxysmal abnormalities induced by photic stimulation abated during clonazepam medication.