ReviewPsychogenic nonepileptic seizures: Answers and questions
Introduction
Based on our current understanding, psychogenic nonepileptic seizures (PNES) are episodes of paroxysmal impairment of self-control associated with a range of motor, sensory, and mental manifestations, which represent an experiential or behavioral response to emotional or social distress. The overwhelming majority of PNES are considered as beyond patients’ voluntary control [1], [2]. However, it is recognized that PNES occur in malingering and factitious disorders [3], and that, short of confession, there are no definitive tests to identify simulated seizures [4].
I have previously contributed to richly referenced review articles that focused on the diagnostic process and the psychological treatment of PNES [5], [6]. These topics have also been very capably reviewed by others [7], [8], [9], [10], [11]. I refer to our previous reviews when they contain information discussed in less detail here. The emphasis on the clinical picture means that theoretical models are relatively neglected in this manuscript. The continuing controversy surrounding the labeling and nosology of PNES is side-stepped completely [12], [13]. In as much as this article is about seizures that neurologists have diagnosed as “nonepileptic” and that they suspect as having a “nonorganic” or “psychogenic” cause, PNES seems an appropriate term for the condition that is being discussed.
Section snippets
Prevalence
The incidence of PNES has been reported as 1.4 per 100,000 [14], or 3 per 100,000 per year [15]. However, given the setting of these studies in neurology centers and the fact that only video/EEG-proven cases were counted, this is likely to be an underestimate. An audit of 659 consecutive new patients in a first-seizure clinic reported that 12% had a clinical diagnosis of PNES (which was not confirmed with video/EEG in all cases) [16]. The authors of another study, which reportedly captured all
Epidemiology
We know much more about the frequency with which neurologists diagnose PNES in specialist settings than about the incidence or prevalence of nonepileptic seizure-like expressions of psychological or social distress in the general population. However, one cannot assume that PNES always present as refractory seizure disorders likely to trigger referral to an epilepsy specialist. There may be a group of patients with PNES with much less troublesome seizure disorders. It is also possible that some
Conclusion
Our knowledge of the clinical picture and context of PNES has made only modest progress since Gowers summarized his understanding of “hysteroid” seizures in 1885 [73]. The most significant developments since this time were the clinical introduction of the EEG in the 1930s and video/EEG monitoring in the 1970s. However, these developments have only increased the level of certainty with which PNES can be distinguished from epileptic seizures and have not had much impact on our understanding of
Acknowledgment
I am grateful to Martin Schöndienst for his hints and critical comments.
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