Trial Evaluating the Efficacy and Safety of Perampanel Added to Monotherapy in Participants With Partial Onset Seizures With or Without Secondary Generalization

Inclusion Criteria: * Have a diagnosis of epilepsy with partial onset seizures with or without secondarily generalized seizures according to the International League Against Epilepsy's Classification of Epileptic Seizures (1981) * Need an initial add-on therapy after failure to control seizures with the first or further monotherapy at the optimal dose and duration * Despite antiepileptic drug (AED) treatment within the last 8 weeks, participants must have had greater than or equal to 2 partial onset seizures, and the interval between those seizures should be more than 24 hours prior to Visit 1 (Week 0). * Are currently being treated with stable doses of monotherapy for 8 weeks prior to Visit 1 (Week 0) (Standard AEDs) * If antidepressants or antianxiety drugs are used, participants must be receiving stable doses and administrations of antidepressants or antianxiety drugs for 8 weeks prior to Visit 1 (Week 0) Exclusion Criteria: * Females who are pregnant (positive beta-human chorionic gonadotropin (β-hCG test) or breastfeeding * Presence of previous history of Lennox-Gastaut syndrome * Presence of nonmotor simple partial seizures only * Presence of primary generalized epilepsies or seizures such as absences and/or myoclonic epilepsies * A history of status epilepticus within 12 weeks before Visit 1 (Week 0) * Participants on antipsychotics or who have psychotic disorder(s) or unstable recurrent affective disorder(s) with a history of attempted suicide within 1 year before …