After a brief review over the role of epilepsy in Public Health, including its overall prevalence rates, the authors describe a study carried out in a Public Hospital's out-patient clinic in Rio de Janeiro. From November-1979 to June-1984, 782 patients, whose files served as source of data, were included in the study. From these 782 patients, 532 (68%) fulfilled Gastaut's electro-clinic criteria for epilepsy, being 416 ( 78,2%) in the group of generalized, 115 (21,6%) in the group of partial or focal and 1 (0,2%) with unilateral presentation. Other 69 patients were considered as having epilepsy, but did not fulfill Gastaut's criteria, due to associations of two or more types of epilepsy. Therefore, of 782 patients, 601 (76,9%) had the diagnosis of epilepsy; 58 of them (7,4%) had epilepsy-like conditions, that is, fainting, migraine, "gasping", sleep-walking;33 (4,2%)of them had a well-defined mental illness but an anti-convulsivant drug treatment was initiated before they were send to the mentioned clinic; in 90 (11,5%) patients the investigation was not accomplished. The onset of the first signs of epilepsy did happen before the age of 20 years in 78,4% patients and in 31,1% of them until the 4th year of Ufe. This negative correlation of increasing age and first signs of disease onset was statistically significant (p < 0,01).
