Perampanel (Fycompa) is a newer anti-epileptic drug believed to exert its effects in the central nervous system by inhibiting post-synaptic glutamate receptors. However, the precise therapeutic mechanism is unknown. The most common neuropsychiatric side effect is affective dysregulation; there are also reports of psychosis. We describe a 32 year old African American male with recurring generalized tonic-clonic (GTC) seizures, who presented to our hospital with onset of mood lability for several months, after Perampanel was added to his antiepileptic medications. Perampanel administration was temporarily withheld, and subsequently on restarting, noted to be coincident with neuropsychiatric symptomatology, including motor weakness in emotional contexts. The mechanisms underlying cataplexy are complex and, in our patient, most likely induced by an interaction between Perampanel and the wakeful inhibition of the sublaterodorsal nucleus projections.