What are those and how are those terms related to psychogenic nonepileptic seizures (PNES)?

FAQs about psychogenic nonepileptic seizures (PNES)

I heard other terms such as "functional neurological disorder", "conversion disorder", "dissociative disorders" and "somatic symptom disorder". What are those and how are those terms related to psychogenic nonepileptic seizures (PNES)?

According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), PNES is considered a subtype of functional neurological symptom disorder (abbreviated FNSD), or functional neurological disorder (abbreviated FND), or conversion disorder. They all mean the same thing!

Functional neurological disorder (or conversion disorder/FNSD) refers to neurological symptoms that are not consistent with how the brain usually operates when there is a structural damage. The symptoms can include seizure-like episodes (PNES), weakness, numbness, gait problems, movement problems, etc. The key in the diagnosis is to prove that the parts of the brain leading to the symptom can function fine at times, which demonstrates that the symptom happens because of a temporary disruption of how the brain is putting those functions together at other times. This is also proof that the symptoms in FND (including PNES) are reversible. Patients with PNES may experience other types of functional neurological symptoms (for example, weakness, abnormal movements, gait problems), before, while or after they develop PNES. It is thus not uncommon for patients with PNES to also have other functional neurological symptoms. Your doctor should be able to answer (or refer you to the proper specialist) if the other neurological symptoms you experience represent other manifestations of FND or not.

Dissociative disorders refer to conditions in which certain mental functionals (such as memory, personal identity, perception of oneself) are disrupted and not properly integrated. For instance, in dissociative amnesia, you may experience amnesia (memory loss) for an extended period of time from your past and from actions that you performed - this occurs without your knowledge. In some classifications of disease, PNES are considered a "dissociative disorder" (because many times there is an impairment in awareness during the episodes).

Somatic symptom disorder refers to a condition in which one or more physical symptoms are causing distress, explained or not by a medical diagnosis, and these symptoms lead to excessive thinking, emotional and/or behavioral disturbances.