Possible candidates were identified by both (1) a prospective observation of patients admitted for the first time to epilepsy centers participating in the study from January 2004 to January 2008, and (2) retrospectively reviewing all clinical records from the databases of the centers. All candidates in the second group with long-lasting disease followed for many years had a seizure diary and clinical evaluation visits at least every 6 months. The data from each patient were tabulated with full details of seizure type, auras, seizure frequency, response to therapy, antiepileptic drug (AED) used, ictal and interictal EEG recording, neuroradiologic findings, and presurgical and surgical evaluation with histopathologic data. Other clinical items tabulated were sex, dominance, family history, personal antecedents, age at seizure onset, delay between seizure onset and diagnosis, follow-up duration, delay between onset of partial seizures with autonomic symptoms and secondarily generalized tonic or tonic–clonic seizures, family history (for FS and/or epilepsy), and potential personal antecedent events such as severe asphyxia, severe head injury, viral encephalitis, bacterial meningitis or cerebral abscess, and FS. FS were differentiated according to Hirtz et al. (1997) into simple (lasting <10 min), complex (lasting from 10–29 min), and febrile status epilepticus (seizures lasting more than 30 min). All patients underwent repeated EEG recordings during wakefulness and, when possible, during diurnal sleep induced by sleep deprivation. Clinical, neuroradiologic, and electrophysiologic data were tabulated with full details in a database developed ad hoc for this study. On the basis of the outcome after medical treatment, patients were divided into drug-resistant (DR) and resistant (NDR). We defined drug resistance according to Perucca (1998) as the persistence of seizures after adequate trials with at least three antiepileptic drugs used in monotherapy or in polytherapy at the maximally tolerated dosage (excluding situations where a meaningful dose escalation is prevented by allergic or idiosyncratic adverse reactions) and when, by their nature and frequency, the seizures compromise quality of life (Perucca, 1998). We considered responsive (NDR) those patients who were seizure free for at least 2 years. We studied the relationship with drug resistance and all the clinical and instrumental variables examined. Patients with a brain lesion detectable on MRI were defined as lesional (LES); patients without clear-cut neuroradiologic abnormalities, including patients with aspecific alterations (i.e., mild cortical atrophy or leukoaraiosis), were deemed nonlesional (NLES). The DR patients were differentiated into operated and not-operated, depending on surgical treatment. We defined as familiar (F) those patients with at least a first- and second-degree relative with a history of epilepsy or FS, and sporadic (S) cases without first- and second-degree relatives with epilepsy or FS. As to the frequency of the secondarily generalized seizures (SG), we considered “frequent SG” as daily, weekly, monthly; “rare” SG as annual, sporadic, unique. Surgical outcome was based on Engel’s classification using all 13 subclasses (Engel, 1987).