What are nonepileptic seizures?

Nonepileptic seizures (NESs) are episodic paroxysmal events that resemble epileptic seizures in many respects. Such events are often difficult, if not impossible, to differentiate from events due to epilepsy, and misdiagnosis leads to inappropriate treatment with antiepileptic drugs (AEDs).

To arrive at an accurate diagnosis, the clinician first must differentiate between the two major types of NESs:

• Psychogenic NESs are symptoms of an underlying psychiatric disorder, without a physiologic basis.
• Physiologic NESs are caused by physiologic dysfunction, such as cardiac arrhythmias, hypotensive episodes, or cerebrovascular disease. Such conditions may result in loss of consciousness, with or without associated motor manifestations. A detailed history and appropriate investigations (e.g., Holter monitoring, noninvasive carotid artery studies, or tilt-table testing) will usually reveal the true diagnosis.

Most of the discussion in this part of epilepsy.com pertains to psychogenic NESs.

Why is an understanding of nonepileptic seizures important?

NESs are relatively common. As many as 20% of the population seen in specialized seizure clinics may suffer from NESs. Put another way, about 50,000 persons in the United States have NESs.

NESs may remain undiagnosed for years. If the patient has a past history of epilepsy and experiences a recurrence of seizures or currently has epileptic seizures and a new seizure type develops, the true diagnosis may be obscured. The clinician usually does not witness the seizures and must rely on information provided by the patient, an outside observer, or both.

Mistakenly attributing NESs to epilepsy generally leads to futile treatment with AEDs. Continuing seizures in spite of increasing AED dosage or multiple AEDs is frustrating for patient and physician alike. Moreover, AED therapy may lead to toxic side effects, causing additional disability and frustration. A correct diagnosis will lead to appropriate psychiatric intervention, discontinuation of AED therapy, and improvement in the patient's quality of life.

Adapted from: Rowan AJ. Diagnosis and management of nonepileptic seizures. In: Schachter SC, Schomer DL, eds. The comprehensive evaluation and treatment of epilepsy. San Diego, CA: Academic Press; 1997. p. 173-184.
With permission from Elsevier (www.elsevier.com)
Reviewed February 2004 by Orrin Devinsky, MD, New York University