Psychogenic nonepileptic seizures (PNES) is the final diagnosis in approximately 30% of patients presenting to specialized epilepsy centers for intractable epilepsy.1–3 PNES specifically related panic and dissociative disorders are a (psychiatric) subtype of PNES and are addressed in separate chapters. This chapter deals with other types of PNES, which represent the vast majority of psychogenic attacks seen at epilepsy centers.
The advent of the widespread availability of video-encephalography (EEG) has led to the recognition that many patients treated on the assumption of having intractable epilepsy indeed do not have epilepsy. There are many different etiologies of nonepileptic spells, but this chapter will concentrate on spells with a clear psychogenic origin, which account for >50% of the misdiagnosis of epilepsy4 in general referral clinics and up to 90% in tertiary epilepsy clinics.5 Commonly called psychogenic nonepileptic seizures, these are spells that clearly have a psychogenic component and are not epileptic in origin. The literature is full of confusing terms, such as hysterical seizures, nonorganic seizures, functional seizures, stress seizures, and pseudoseizures, but PNES has become the preferred term. Such seizures are felt to be a conversion disorder manifested by spells that imitate seizures. They are subconscious in origin and very real to the patient. They are differentiated from the far less common condition of malingering or factitious disorder, in which patients consciously fake a seizure for secondary gain, as well as nonepileptic spells with a nonpsychogenic etiology, such as syncope and movement disorders.
PNES is diagnosed fairly often in the general population, with an estimated prevalence of 2 to 33 per 100,000, making it nearly as common as multiple sclerosis and trigeminal neuralgia.6 The diagnosis can be made with near certainty by the use of video-EEG monitoring (VEM). Establishing this diagnosis minimizes the risks from antiepileptic drugs and inappropriate medical treatment. It also helps steer the patient toward more effective treatment and minimizes the wasting of the patient's and society's health care resources.
Age of Onset and Gender Distribution
The vast majority of patients with PNES are women between the ages of 20 and 50 years. This is consistent across most large published series7,8 and even across cultures.9 There is a growing literature about both younger and older age groups, but they are distinctly less common. A study of the Veterans Affairs (VA) population found 9.6% of PNES patients are older than 60 years.10 Patients with late-onset PNES are proportionally more often men, have more chronic medical illness, and may be more likely to exhibit trembling rather than violent thrashing.11 Even though the elderly are a small percentage of PNES, PNES is found in a significant percentage of patients admitted for VEM. In one study of 94 elderly (>age 60) patients admitted for VEM, PNES was diagnosed in 13 (14%).12 Similarly, in ...