For treatment of epilepsy in patients of adolescence and adulthood, we always take into account all the 3 aspects of 1) diagnosis of seizure type and epilepsy syndrome, 2) existence of comorbidity and 3) interaction between concomitant drugs, and thus an appropriate treatment approach is individualized. The first line antiepileptic drug (AED) used for focal seizure or epilepsy is carbamazepine, and the first line AED for generalized seizure or epilepsy is valproic acid. If monotherapy with these drugs is insufficient, it is recommended to change to another drug or to add other drugs. For add-on therapy, the interaction between drugs should be considered. If polytherapy with these drugs is insufficient, diagnosis are again carefully checked, and further examination for resective epilepsy surgery or vagus nerve stimulation is considered.