July 2010
Reviewer: Jeff C. Huffman, MD
Clinical characteristics and outcome in patients with psychogenic nonepileptic seizures
Jones SG, O’Brien TJ, Adams SJ, et al
Psychosom Med 2010; 72(5):487-497
Background: Approximately one-quarter of patients referred to epilepsy centers are diagnosed with psychogenic nonepileptic seizures (PNES). Patients with PNES appear to have chronic and substantial impairment of function and are high utilizers of health care. Despite the frequency and importance of these disorders, there is only scattered literature on the characteristics and longer-term outcomes of patients with PNES. The authors aimed to identify baseline clinical features of a large cohort of PNES patients and to assess the medical, psychiatric, and treatment outcomes of these patients.
Methods: Subjects were retrospectively identified from consecutive admissions for comprehensive epilepsy evaluation (5 day minimum, including video EEG monitoring, brain imaging, and neuropsychiatric assessment) at a tertiary referral center in Australia over a 9 year period (1995-2004). Possible PNES patients were identified using recorded discharge diagnoses, and PNES diagnosis was made by the study team after comprehensive chart review, using specific criteria (including occurrence of a typical episode with no epileptiform activity on EEG). Baseline data were recorded via chart review; such data included whether the patient had a comorbid epilepsy diagnosis (based on events in the hospital or past documentation). For patients identified as having PNES, a follow-up packet was sent (October 2005-January 2006). This packet contained: (1) a follow-up assessment sheet for demographic, medical, medication, and PNES event information, (2) a quality of life scale (QOLIE-89), (3) a psychiatric symptom checklist (SCL-90-R), and (4) a global outcome measure related to event frequency and disability status.
Results: Of 421 patients with possible PNES based on discharge diagnosis, a total of 221 patients met study criteria for ‘proven PNES.’ Such patients had symptoms for a mean of 5.6 years before the evaluation admission. Overall, 14% of these patients had confirmed comorbid epilepsy based on video EEG events at admission or prior EEG with epileptiform discharges. Approximately two-thirds of patients were taking antiepileptics on admission, 73% of whom had no evidence of epilepsy. Of the 174 patients who had neuropsychiatric assessments in the hospital, 139 (80%) had a psychiatric diagnosis recorded or had sufficient past record evidence to make such a diagnosis.
With regard to follow-up data, 61 subjects (27.6%) responded; responders and nonresponders were not significantly different with regard to comorbid epilepsy, psychiatric history, or most baseline characteristics. Overall, 83% of patients had a PNES event in the last year, over 50% averaged more than one event per month, and 36% had another PNES-related admission. Fifty-six percent reported having PNES or a disorder related to stress; 39% reported having epilepsy or were uncertain about their diagnosis. Forty percent remained on anticonvulsants. Psychiatrically, 43% had been referred for psychological treatment, more than half reported having “current mental health problems” (primarily depression and anxiety), and 20% were taking psychotropic medications. Finally, patients quality of life scores were significantly lower than norms for patients with epilepsy, especially with regard to physical symptoms, role limitation, emotional well-being, and health perception.
Discussion: This is an important step in the work that is being done to understand patients with PNES. This study had a rather large cohort of patients with PNES, was able to review thorough admission workups for such patients that provided much background data and information about their episodes, and provided important follow-up information about these patients, often years down the road.
The patients with PNES in this study had prolonged symptoms for several years prior to the evaluation admission and diagnosis of PNES, had high rates of comorbid psychiatric disorders, and were often on one or more anticonvulsants (even after the diagnosis). Despite the thorough evaluation they received during the admission, the patients continued to have recurrent PNES events (often at a frequency of greater than one per month), and they reported their quality of life as worse than the average patient with true epilepsy from both a physical and emotional standpoint.
This study had multiple limitations. The most important were the retrospective nature of the study that required the study team to piece together history of prior seizures and psychiatric diagnoses assessed during the admission, the nature of the tertiary referral center (i.e., patients with more prolonged, chronic, or severe cases of PNES may have been referred there, and patients with mild or more transient symptoms may not have been referred), and the very low rate of response to the follow-up questionnaires, which calls into question the generalizability of the responses.
Still, this work paints a fairly comprehensive and daunting picture of at least this subset of patients with PNES. It should prompt us to comprehensively assess these patients from a physical and psychological standpoint, ensure that they understand their diagnosis, treat the frequently-occurring comorbid psychiatric disorders, and continue our investigation into specific treatments that help these patients, given the clear negative impact of PNES on the quality of life of patients like those studied in this cohort.