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  • Updated 03.21.2023
  • Released 07.26.1994
  • Expires For CME 03.21.2026

Functional, dissociative, or psychogenic nonepileptic seizures



The terms functional and dissociative both refer to seizures that are associated with increased connection between limbic or emotional brain areas and higher-level motor networks. Previously known by the contentious terms pseudoseizures and psychogenic nonepileptic seizures (PNES), these seizures are associated with biopsychosocial stressors and are not caused by epileptic abnormality.

Functional or dissociative seizures often challenge even experienced epilepsy experts in their diagnosis because of their behavioral overlap with epileptic seizures, their potential comorbidity with epilepsy, and the limited quality of patient and witness descriptions of seizures. Once diagnosed, they pose the additional challenges of understanding their cause and providing effective treatment. In this review, the fundamental clinical aspects of functional seizures are surveyed, including issues of differential diagnosis, prognosis, and management.

Key points

• Functional seizures may appear similar to epileptic seizures and often result in misdiagnosis as epilepsy.

• Functional seizures are involuntary and often disabling.

• Accurate and early diagnosis of functional seizures leads to more appropriate and effective healthcare resource utilization.

• With psychotherapy targeted towards functional seizures, roughly 80% of patients will have a greater than 50% reduction in seizure frequency and improvement in quality of life.

• Functional seizures should not be treated as epileptic seizures. Antiseizure medications with psychotropic effects can treat psychiatric comorbidities in patients with functional seizures but are not recommended as first-line treatments.

Historical note and terminology

There is substantial debate and strong disagreement regarding the appropriate and sensitive terminology regarding patients’ events. This debate has intensified over the past few years (08; 69; 13; 69; 134). Although inappropriate and offensive terminology is widespread, its use can cause real harm to the therapeutic relationship between patient and provider, especially in the emergency setting (113). Each of the following phrases is typically used and acceptable for clinical practice:

• Functional seizures
• Dissociative seizures
• Nonepileptic seizures
• Nonepileptic events
• Conversion disorder with seizures or attacks
• Functional neurologic disorder with seizures or attacks

The International League Against Epilepsy (ILAE) still uses the following terms, although there is increasing movement against them due to offending as many as one in four patients with the condition (124; 123).

• Psychogenic nonepileptic seizures
• Psychogenic nonepileptic attacks
• Psychogenic nonepileptic attack disorder

The terminology debate focuses on both the descriptors and the noun. The term adopted by the ILAE is psychogenic nonepileptic seizures, whereas the other preferred terms are dissociative seizures or functional seizures. Some patients and a minority of providers consider “psychogenic” a pejorative term because it is connected to the stigma of psychological disease. The term “dissociative seizures” is appropriate because during events the patient’s physical movements or mental status dissociates from conscious control. The term “functional seizures” unifies the condition with the broader category of functional neurologic disorders, including functional tremor, functional weakness, and functional cognitive disorders. In cases where a psychiatric etiology is resisted, the general term “nonepileptic seizures” is acceptable.

The discussion regarding the noun balances the assumed interpretation of the word “seizure” with the nonspecific nature of the terms “attack” or “events.” Although both providers and the lay public tend to understand a seizure as an epileptic seizure, the Greek word originally means “to take hold.” By removing the term “seizure,” one can clearly express that antiseizure medication should not be used to treat them. However, the patient’s experience of the events is similar to seizures and untrained observers describe the events as seizures, so changing the term would constantly challenge the patient’s understanding of how to describe the events; also, the terms “events” or “attacks” diminish the severity of the term and are nonspecific. Additionally, as LaFrance discussed, many patients with functional seizures have been attacked physically, sexually, and emotionally, and the seizures are very different from these original attacks, so the term “attacks” is less desirable (76; 64). Yet another alternative includes “convulsions,” which does not describe the substantial population of patients with nonmotor psychogenic nonepileptic seizures (07).

The discussion regarding the descriptor focuses on choosing a term that highlights the appropriate psychiatric mechanism while not offending patients. The terms “hystericoepilepsy” and “pseudoseizure” are both offensive to patients and not appropriate descriptors because these seizures are not a subtype of epilepsy and they are not “fake” or “false” (123). Instead, they are real and markedly disabling to the patient. We highly discourage the use of these terms. Similarly, we highly discourage describing epileptic seizures as “true” or “real.” The ILAE adopted term of “psychogenic” is a corollary of “epileptogenic” that describes the region of the brain that is necessary and sufficient for the occurrence of epileptic seizures. However, the root word of “psycho” can make the patient feel as though they are labeled as a “psycho” in lay terms, and is similar in its offensiveness to pseudoseizures in patient surveys (123). “Functional” is a neutral term that does not offend, but is a code word without much meaning, and does not match the dysfunction caused by the seizures. In contrast, the terms “dissociative” and “conversion disorder” have specific definitions in psychiatry and suggest psychiatric mechanisms that have yet to be established. The ICD-10 and DSM-5 classify functional seizures under conversion disorder and no longer require identification of a stressor causing the events because, in about 10% to 15% of patients, a stressor cannot be identified. This nosology reflects how functional seizures do not fit under the subtypes of dissociative disorders in the DSM-5.

The descriptor “nonepileptic” can be used instead of or in addition to the descriptors above. In patients resistant to the stigma of psychiatric disorders, the nonspecific term “nonepileptic seizures” can maintain the therapeutic alliance while also motivating acute removal of antiseizure medication prior to discharge from video-EEG units, which may improve future outcomes (37). In our opinion, the term nonepileptic seizures is unnecessarily vague because it does not adequately distinguish psychogenic nonepileptic seizures from physiologic nonepileptic seizures, including but not limited to convulsive syncope, complex migraines, movement disorders, parasomnias, or other paroxysmal events. Further, this equates to defining nonepileptic seizures by what they are not, which does not reflect the current understanding that functional neurologic disorders can be a positive diagnosis with clear associated factors. The concept that functional neurologic disorders is a diagnosis of exclusion may lead to delays in appropriate care and thereby worse outcomes (67; 70).

In general, we recommend choosing the terminology that the provider feels can be understood and accepted by the patient as descriptive of their seizures. Anecdotally, some patients have felt empowered when we involved them in the decision regarding how to describe their events. Further information discussing both patient and provider perspectives regarding terminology is available through the Functional Neurological Disorder Society.

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