Psychogenic non-epileptic seizure

The number of people with PNES ranges from 2 to 33 per 100,000.^[7] PNES are most common in young adults, particularly women.^[7] The prevalence for PNES is estimated to make up 5–20% of outpatient epilepsy clinics; 75–80% of these diagnoses are given to female patients and 83% are to individuals between 15 and 35 years old.^[8]

PNES are seen in children after the age of eight, and occur equally among boys and girls before puberty. Diagnostic and treatment principles are similar to those for adults, except that in children there is a broader differential diagnosis of seizures so that other possible diagnoses specific to children may be considered.^[9]

PNES episodes can be difficult to distinguish from epileptic seizures without the use of long-term video EEG monitoring. Some characteristics which may distinguish PNES from epileptic seizures include gradual onset, out-of-phase limb movement (in which left and right extremities jerk asynchronously or in opposite directions, as opposed to rhythmically and simultaneously as in epileptic seizures), closed eyes, high memory recall, and lack of post-ictal confusion.^[10][11][12] Although these symptoms are possible in epileptic seizures, they are much more commonly found in PNES.

PNES episodes are often less injurious than epileptic seizures. Unlike epilepsy, many PNES patients presenting with total unresponsiveness still retain some form of conscious response, including the natural behavior to protect oneself from harm. This is often reflected by a lack of tongue-biting, urinary and/or fecal incontinence, fall-related trauma, or accidental burns, all of which are significantly less common in PNES than in epileptic seizures.^[10][11] Other means of determining consciousness include dropping a patient's hand above the nasopharyngeal lead; the natural response is to prevent it from falling. Visual tracking and resistance to passive eye movements can also be used to determine PNES when the eyes are open.^[10] However, total unresponsiveness is possible in PNES, and lack of conscious response on its own is not enough to indicate an epileptic seizure.

While most epileptic seizures last no more than two minutes, PNES episodes may last five minutes or longer. An epileptic seizure lasting longer than five minutes is considered a life-threatening medical emergency, which is not a risk in PNES.

The cause of PNES has not yet been established. One hypothesis is that they are a learned physical reaction or habit the body develops, similar to a reflex. The individual does not have control of the learned reaction, but this can be retrained to allow the patient to control the physical movements again.^[13] The production of seizure-like symptoms is not under voluntary control;^[14][15] symptoms which are feigned or faked voluntarily would fall under the categories of factitious disorder or malingering.^[16]

Risk factors for PNES include having a history of head injury, and having a diagnosis of epilepsy.^[17] Approximately 10–30% of people diagnosed with PNES also have an epilepsy diagnosis. People diagnosed with PNES commonly report physical, sexual, or emotional trauma, but the reported incidence of these events may not differ between PNES and epilepsy.^[18]

According to the Diagnostic and Statistical Manual of Mental Disorders (version 5) the criteria for receiving a diagnosis of PNES are:^[19]

1. One or more symptoms of altered voluntary motor or sensory function.
2. Clinical findings provide evidence of incompatibility between the symptom and recognized neurological or medical conditions.
3. The symptom or deficit is not better explained by another medical or mental disorder.
4. The symptom or deficit causes clinically significant distress or impairment in social, occupational, or other important areas of functioning or warrants medical evaluation.

Additionally, the specific symptom type must be reported "with attacks or seizures".^[19]

Some individuals with PNES have carried an erroneous diagnosis of epilepsy. On average, it takes seven years to receive a proper diagnosis. The differential diagnosis of PNES firstly involves ruling out epilepsy as the cause of the seizure episodes, along with other organic causes of non-epileptic seizures, including syncope, migraine, vertigo, anoxia, hypoglycemia, and stroke. However, 5–20% of people with PNES also have epilepsy.^[20] Frontal lobe seizures can be mistaken for PNES, though these tend to have shorter duration, stereotyped patterns of movements, and occurrence during sleep.^[21] Next, an exclusion of factitious disorder (a subconscious somatic symptom disorder, where seizures are caused by psychological reasons) and malingering (simulating seizures intentionally for conscious personal gain – such as monetary compensation or avoidance of criminal punishment) is conducted. Finally other psychiatric conditions that may superficially resemble seizures are eliminated, including panic disorder, schizophrenia, and depersonalization derealization disorder.^[21]

The most definitive test to distinguish epilepsy from PNES is long term video-EEG monitoring, with the aim of capturing one or two episodes on both video recording and electroencephalography (EEG) simultaneously (some clinicians may use suggestion to attempt to trigger an episode).^[22] Additional clinical criteria are usually considered in addition to video-EEG monitoring when diagnosing PNES.^[23] By recording the event in question on video and EEG simultaneously, a clear diagnosis can usually be obtained.^[24]

Laboratory testing can detect rising blood levels of serum prolactin if samples are taken in the right time window after most tonic-clonic or complex partial epileptic seizures. However, due to false positives and variability in results, this test is relied upon less frequently.^[21]

Patient understanding of the new diagnosis is crucial for their treatment, which requires their active participation.^[25] A negative diagnosis experience may cause frustration and could cause a person to reject any further attempts at treatment. Psychotherapy, particularly cognitive behavioral therapy, is most frequently used to treat PNES. There is also some evidence supporting selective serotonin reuptake inhibitor antidepressants.^[26]

Retraining and Control Therapy (ReACT)

ReACT, while new and understudied, has shown extremely promising outcomes for reduction of PNES episodes in pediatric patients.^[27] This therapy focuses on the idea that PNES are caused by a learned physical reaction or habit the body develops, similar to a reflex. ReACT aims to retrain the learned reaction (PNES episodes) by targeting symptom catastrophizing and restoring sense of control over symptoms.

For individuals who pursue treatment for PNES, CBT has shown varying rates of success but it has been established as one of the most promising treatments to date.^[28] ReACT has shown reduction in symptoms by 100% seven days after treatment and 82% of individuals who completed the therapy remained symptom free for 60 days. A follow-up has not been done to see if the therapy retained its reduction of symptoms beyond the 60 days.^[27] In the cognitive behavioral therapy for adults with dissociative seizures (CODES) trial, the largest regarding CBT treatment for PNES though found no significant reduction in monthly episodes compared to the control arm at 12 months, however there were significant improvements on a number of secondary outcomes, such as psychosocial functioning, and self-rated and clinician-rated global change.^[29] A secondary analysis of the CODES trial demonstrated improved frequency of PNES episodes at 6 months with CBT.

Hystero-epilepsy is a historical term that refers to a condition described by 19th-century French neurologist Jean-Martin Charcot^[30] where people with neuroses "acquired" symptoms resembling seizures as a result of being treated on the same ward as people who genuinely had epilepsy.

The etiology of FND was historically explained in the context of psychoanalytic theory as a physical manifestation of psychological distress and repressed trauma. There is very little supporting evidence for this theory, as there is little research.^[31]

The DSM-IV lists conversion disorders instead of the current FND. Additionally, in revision, the DSM-5 was updated to add emphasis to the positive physical signs inconsistent with recognized diseases. The requirement of a history of psychological stressors and that the symptom is not fake was removed as well.^[32]

PNES rates and presenting symptoms are somewhat dependent on the culture and society. In some cultures, they, like epilepsy, are thought of as a curse or a demonic possession.^[33] In cultures with a solid establishment of evidence-based medicine, they are considered a subtype of a larger category of psychiatric disease.

The term PNES is sometimes considered a misnomer, because the word "seizure" refers to a surge of electrical discharges in the brain, which does not occur in PNES episodes. Many prefer to use more general terms like "spells," "events," "attacks," or "episodes."^[34] "Non-epileptic attack disorder," or NEAD, is typically used in the UK for this reason.^[35] The use of older terms including pseudoseizures and hysterical seizures are discouraged.^[36]

Within DSM 5, patients presenting with PNES may meet the criteria for functional neurological disorder and in some cases, somatic symptom disorder, whilst in ICD 10 it may meet the criteria for a conversion disorder.^[21]