To date neurobiological interest in the behavioral consequences of epilepsy has been concerned primarily with the neuropsychology of temporal lobe epilepsy (TLE) and of mesial temporal lobe epilepsy (mTLE) in particular. In epilepsy several factors can be discerned, which can lead to dynamic and principally reversible changes in the patient's behaviors and mood states. The patient with epilepsy must always be seen in his or her state relative to seizures. Epileptic activity can affect distant brain areas and cause cognitive and behavioral problems beyond the primary lesion. Antiepileptic drugs may have positive or negative psychotropic side effects, and can show incompatibilities in the individual patient. Very special behavioral and neuropsychological conditions are met during nonconvulsive status epilepticus (NCSE). The chapter concludes that in temporal and frontal lobe epilepsy dysfunctional behaviors can be discerned which characteristically correspond to the affected brain regions.