Sleep in psychogenic nonepileptic seizures and related disorders.

Psychogenic nonepileptic seizures (PNES), a form of functional neurological symptom disorder (FNSD), are very rarely seen in genuine, electroencephalography (EEG)-confirmed sleep. However, they are more commonly reported as a nocturnal occurrence, likely from a state that is misidentified as sleep (termed by some as "pseudosleep"). Sleep state can be helpful to distinguish FNSD from other neurological disorders. Pseudo-cataplexy, a form of "psychogenic" narcolepsy, "pseudo-parasomnia" and PNES can have a similar presentation. PNES and posttraumatic stress disorder (PTSD) frequently share previously experienced psychological trauma, and therefore the sleep abnormalities found in PTSD may be similarly present in PNES. Future research should use EEG monitoring to evaluate the sleep physiology of patients with FNSD such as PNES, as insights into sleep abnormalities may enable further understanding of the etiology and manifestations of PNES.