Psychogenic nonepileptic seizures: answers and questions.

Psychogenic nonepileptic seizures (PNES) superficially resemble epileptic seizures, but are not associated with ictal electrical discharges in the brain. PNES constitute one of the most important differential diagnoses of epilepsy. However, despite the fact they have been recognized as a distinctive clinical phenomenon for centuries and that access to video/EEG monitoring has allowed clinicians to make near-certain diagnoses for several decades, our understanding of the etiology, underlying mental processes, and, subsequently, subdifferentiation, nosology, and treatment remains seriously deficient. Emphasizing the clinical picture throughout, the first part of this article is intended to "look and look again" at what we know about the epidemiology, semiology, clinical context, treatment, and prognosis of PNES. The second part is dedicated to the questions that remain to be answered. It argues that the most important reason our understanding of PNES remains limited is the focus on the visible manifestations of PNES or the seizures themselves. In contrast, subjective seizure manifestations and the biographic or clinical context in which they occur have been relatively neglected.