Functional seizure (psychogenic nonepileptic seizure)
Functional seizures (psychogenic nonepileptic seizures/events, PNES) are paroxysmal episodes resembling epileptic seizures but caused by a functional disturbance of the nervous system rather than abnormal cortical electrical discharge. Diagnosis requires video-EEG capturing a typical event with no ictal correlate; management is multidisciplinary, centered on diagnosis disclosure and psychotherapy, not antiseizure drugs.
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What this article covers
- Overview
Definition: functional seizures, also called psychogenic nonepileptic seizures or events (PNES), are paroxysmal episodes of altered movement, sensation, or awareness that resemble epileptic seizures…
- Epidemiology
Substantial burden in epilepsy referral populations: PNES accounts for roughly 20 to 30% of patients referred to epilepsy monitoring units for medically refractory "epilepsy," reflecting frequent community misdiagnosis.
- Risk factors
Psychological trauma: a history of sexual or physical abuse, combat exposure, or other significant life stressors is the most consistently identified risk factor.
- Pathophysiology
Not epileptic: video-EEG shows no epileptiform discharge before, during, or after a typical event, and the episodes are not caused by abnormal paroxysmal electrical activity of the brain.
- Clinical features
Variable, non-stereotyped semiology: unlike epileptic seizures, which are typically stereotyped for a given patient, PNES events often vary in appearance from episode to episode.
- Differential diagnosis
Generalized tonic-clonic epileptic seizure: stereotyped, open eyes, synchronous tonic-then-clonic activity, a single sharp ictal cry, duration usually under 2 minutes, and a true postictal confusion…
- Diagnosis
Video-EEG monitoring capturing a typical event is the diagnostic gold standard: the diagnosis is established when the patient's characteristic episode is recorded on video with EEG showing no…
- Management
First, deliver the diagnosis clearly and without stigma, using the video-EEG findings to explain that the events are real and involuntary but are not caused by epileptic electrical activity, and that…
- Complications
Iatrogenic harm from misdiagnosis: unnecessary antiseizure drug exposure, medication side effects, and, in some cases, inappropriate escalation to intubation for presumed status epilepticus.
- Prognosis
Favorable with early diagnosis and treatment: patients started on PNES-specific psychotherapy soon after onset have meaningfully better outcomes than those with a long delay to diagnosis.
- Prevention
No primary prevention strategy exists for functional seizures, since the underlying psychological vulnerabilities and trauma histories are not readily modifiable in advance.
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Related articles
- Functional neurologic symptom disorder
Functional neurologic symptom disorder (conversion disorder) causes real, involuntary weakness, sensory loss, movement abnormality, or non-epileptic attacks that are incompatible with recognized neurologic disease on careful examination. Diagnosis rests on positive bedside signs of incongruity (Hoover sign, tremor entrainment) rather than exclusion alone; first-line treatment is diagnosis explanation plus physiotherapy or cognitive behavioral therapy, not antiseizure or other disease-specific drugs.
- Epilepsy
Epilepsy is a disease of recurrent unprovoked seizures, defined as two unprovoked seizures more than 24 hours apart or one unprovoked seizure with at least a 60% recurrence risk; treatment is guided by seizure type, with levetiracetam or lamotrigine preferred first-line for most adults.
- Seizure (first, single, or provoked)
A first or provoked seizure requires a focused history to distinguish it from syncope or a nonepileptic event, urgent glucose and electrolyte testing, brain MRI, and outpatient EEG; an unprovoked seizure with normal imaging and EEG usually does not require antiepileptic drug therapy, since epilepsy is defined only after a second unprovoked seizure or a high-risk first one.
- Status epilepticus
Status epilepticus is a generalized tonic-clonic seizure lasting more than 5 minutes, or repeated seizures without return to baseline, and is a neurologic emergency. Treatment is a timed escalation: IV benzodiazepine first, then an IV antiepileptic drug, then anesthetic coma with continuous EEG if convulsions persist.