Update on Psychogenic Nonepileptic Seizures
Update on Psychogenic Nonepileptic Seizures
Psychogenic nonepileptic seizures (PNES) are episodes of altered movement, sensation, or reported experience that mimic epileptic seizures (ES) but are not the result of abnormal electrical discharges from the brain. Rather, they are presumed to be “caused” by emotional trauma, unresolved conflicts, or other psychological factors; hence the moniker “psychogenic.” But since there is no known mechanism whereby the mind or psyche can produce symptoms of this type, PNES are best appreciated as disorders of behavior.1 This formulation—as a disorder of behavior and not a disease in and of itself—has important implications for how we treat patients with PNES.
Epidemiology and risk factors
In clinical settings, PNES are relatively common. Up to 20% of outpatients with intractable seizures are found to have these behavioral episodes rather than epilepsy; this figure increases to 40% of patients admitted to specialized epilepsy in-patient units.2 In patients who have PNES, the condition typically remains undiagnosed, or incorrectly diagnosed, for 7 to 10 years before the correct diagnosis is made.3 This results in expensive, unnecessary, and sometimes harmful treatment and severely diminished quality of life.
As in many somatoform disorders, PNES is more prevalent in women than in men, and the onset is most often in young adulthood (ages 20 to 30).4 A common risk factor is a history of head trauma. As many as 75% of patients with PNES report having sustained a head injury, and about 20% attribute their seizures to brain injury after mild head trauma. Another risk factor is epilepsy. Approximately 10% of persons with PNES also have ES; this figure reaches 30% in patients with PNES who also have intellectual disability.5
Reports of physical, sexual, or emotional trauma are very common among patients who have PNES. About 70% report one or more severely traumatic events before their first PNES episode. In nearly half of these patients, the trauma is sexual.5 However, several studies find no difference in trauma history between persons with PNES and those with ES.6,7 In addition, the specificity of early-life abuse to the development of seizures later in life has never been established. A history of trauma might therefore best be viewed as a risk or vulnerability factor (like low intelligence and history of head injury) in the genesis of PNES.
Associated psychological disorders
The majority of patients with PNES have preexisting psychiatric disorders, most often major depression or an anxiety disorder.8 Patients typically receive diagnoses of somatoform disorder or dissociative disorder because they have medically unexplainable sensory, motor, and psychic events with alterations of consciousness.9 Many patients with PNES have life-long problems relating to others and receive personality disorders diagnoses. Patients with PNES often have DSM-IV-TR cluster A and B personality disorders, whereas those with ES are more likely to have cluster C personality disorders.10
Health care providers often tell patients that their PNES are “caused by stress.” Testa and colleagues11 investigated whether these patients actually experience more stressful life events than other people. They found that patients with PNES do not sustain more frequent or more severe stressful life events than patients with epilepsy or healthy persons. However, patients with PNES reported more profound distress over negative life events, especially in the domains of work, social functioning, legal matters, and health. They were also less likely to engage in the problem-centered coping strategies of planning (eg, formulating intended actions) and active coping (eg, taking concrete steps to ameliorate the situation) than the other groups in the study.
Although patient in the PNES group did not engage in more denial than the other groups, its use as a coping mechanism was associated with greater perceived distress. These results suggest that teaching patients how to manage life stress—both major stressful events and everyday annoyances—may be an essential component of psychiatric care.
Evaluation and diagnosis
The gold standard for the diagnosis of seizures is video-electroencephalography (video-EEG), whereby behavioral events are observed and recorded with the simultaneous registration of the EEG. This is often accomplished in a specialized epilepsy monitoring center. The absence of epileptiform activity on the EEG before, during, or after a characteristic event suggests the diagnosis of PNES.5
Studies have attempted to determine whether specific semiological elements can help distinguish PNES from epilepsy. Specific movements more commonly associated with PNES than ES include side-to-side head and body movements, pelvic thrusting, and thrashing.4,5,12 PNES often have a fluctuating course and are much longer in duration than ES, which are usually briefer than 3 minutes.5,13 Vocalization often occurs at the end of a PNES event, whereas it occurs at the beginning (when it does occur) of an ES. Furthermore, the vocalization in PNES often has an affective content, and women often cry.10 Finally, memory for the episode is more often associated with PNES, whereas postictal confusion and amnesia characterize ES.5