Factors involved in the long-term prognosis of psychogenic nonepileptic seizures

Abstract

Introduction

Information on the long-term effects of psychogenic nonepileptic seizures (PNES) is limited. We therefore reassessed 22 patients 4-6 years after the initial diagnosis of PNES in a tertiary referral epilepsy center. The diagnosis was confirmed using clinical description and additional electroencephalogram investigations in 1998, 1999, and 2000. Patients with epilepsy and PNES as comorbid symptoms were not included. Reassessments were aimed at seizure reduction and possible psychogenic factors.

Methods

Three psychological tests were used at baseline at the time of diagnosis and repeated at end point. These three tests assessed different “levels” of psychological function [i.e., complaints (The Symptoms Check List Revised), coping strategy (The Dissociation Questionnaire), and personality factors/psychopathology Nederlandse Verkorte MMPI].

Results

Twenty-two patients were included. Seizure frequency showed statistically significant reduction. At the time of diagnosis, none of the patients was seizure-free or had only yearly seizures, whereas at end point, 7 of 22 patients were completely in remission and 3 patients had only occasional seizures. The number of patients with daily seizures dropped from nine to two. It has not been fully clarified which factors caused this improvement, but the common denominators are that a definitive expert diagnosis in a tertiary center was made and all possible efforts were made to inform the patient in a respectful manner about the diagnosis.

In addition to seizure reduction, there was improvement on different levels of psychological function, showing reduction in psychological distress, reduction in dissociative features such as amnesia, increase in self-control, reduction in feelings of dissatisfaction and passive avoidant behavior, and a more active attitude towards social contact.

Conclusion

In the long term, the patients with PNES who were included in our study have more self-control and approach social contact with a more self-confident attitude. This does not necessary reflect a causal relationship with the observed seizure reduction. Nonetheless, it is noteworthy that, post aut propter, the eradication of a symptom (i.e., seizures) with social consequences is followed by or is associated with a more confident social attitude. This opens possibilities for treatment strategies.

Introduction

Psychogenic nonepileptic seizures (PNES) are a relatively frequently reported symptom. For example, 7-10% of patients referred to a specialized epilepsy center in The Netherlands have PNES [1] and, internationally, estimates of up to 33% have been mentioned [2]. In theory, the distinction between epileptic seizures and PNES is evident [3]. Epileptic seizures are the clinical manifestation of a sudden abnormal change in brain function, accompanied by excessive electrical discharge of brain cells. PNES are defined as a sudden disruptive change in a person's behavior, which is usually time-limited and resembles or is mistaken for epilepsy but is not accompanied by abnormal paroxysmal discharges on electroencephalogram (EEG) and occurs as a symptom of emotional disturbances, personality factors, or present or historical social circumstances [4], [5], [6]. Although diagnosis can be difficult, diagnostic features have been better characterized in recent years. Diagnosing PNES is important because of potential iatrogenic hazards. Patients may be diagnosed as suffering from intractable epilepsies and may be overtreated [7]. There are indications that prognosis in the long term may be worse in such cases [8]. In addition, long periods of uncertainty of the diagnosis may have a negative impact on social development and occupational opportunities [9], which again may have long-lasting effects. Comparatively little research has been done on long-term prognosis after the diagnosis [10], [11], [12]. Validated treatments and controlled trials are lacking [13]. Furthermore, follow-up period is mostly relatively short, varying from 3 months to a year after diagnosis [14], [15].

The definition of PNES is hindered by a diversity of conflicting terminologies, such as hysterical seizures, psychogenic seizures, nonepileptic seizures, and functional seizures [16], [17]. In the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, PNES is classified as a “conversion disorder with seizures or convulsions.” This variation in terminology represents a variety of models proposed to explain PNES. In fact, theories regarding the causes of these seizures are probably as diverse as the phenomenology of this type of seizure. Using Diagnostic and Statistical Manual of Mental Disorders, Third Edition criteria, Stewart et al. [18] were able to uncover several forms of psychopathology in patients with PNES, with a clear tendency for the combination of borderline and antisocial personality disorders. A remarkable finding was that hysteria was not a common diagnosis. The synonym “hysterical seizure” for PNES is, therefore, not correct. The variety of theoretical models explaining PNES probably reflects the heterogeneity of the psychogenic etiology of PNES, which can be a symptom of various affective and psychiatric factors [19], [20]. As yet, there is no accepted model explaining the psychogenic factors leading to PNES. There are indications that, often, more than one factor or psychogenic mechanism operate in PNES [15], [21].

Some attempts have been made to classify patients with PNES into distinct groups requiring different types of interventions and with different prognoses [22]. For example, persisting seizures are expected to occur in patients with personality disorders [8], [23], whereas patients who have PNES because of recently experienced extreme stressors are considered relatively easy to treat and may, therefore, have PNES only as a temporary symptom [24]. The outcome may, therefore, help us to identify some psychogenic mechanisms. We lack, however, knowledge about the prognosis of PNES, as most studies are cohort studies that only report on the diagnosis but do not provide follow-up data. Long-term outcome may also help us to distinguish between “subtypes” of PNES, as patients with persistent seizures over time may have different psychogenic mechanisms in comparison to patients with full seizure remission.

With regard to outcome, there are different studies suggesting that seizure control alone is not a comprehensive measure of good medical or psychosocial outcome in PNES [11], [25]. Several studies have shown that other outcomes, such as employment status [26], may be of greater importance for patients. A consensus report on PNES treatment emphasized that if an intervention improved seizure control without changing the hypothesized etiology, the validity of the treatment could be called into question [13].

In this study, we will therefore reassess patients diagnosed with PNES 4-6 years after the initial diagnosis in a tertiary referral epilepsy center. Reassessments will be aimed at seizure frequency and possible psychogenic outcomes.