- Email: [email protected]
Using personality disorders to distinguish between patients with psychogenic nonepileptic seizures and those with epileptic seizures
Epilepsy & Behavior 23 (2012) 138–141
Contents lists available at SciVerse ScienceDirect
Epilepsy & Behavior journal homepage: www.elsevier.com/locate/yebeh
Using personality disorders to distinguish between patients with psychogenic nonepileptic seizures and those with epileptic seizures Nese Direk a,⁎, Isin Baral Kulaksizoglu b, Kadriye Alpay c, Candan Gurses d a
Department of Epidemiology, Erasmus Medical Centre, Rotterdam, The Netherlands Department of Psychiatry, Istanbul School of Medicine, Istanbul University, Istanbul, Turkey Department of Neurology, Gebze Central Hospital, Kocaeli, Turkey d Department of Neurology, Istanbul School of Medicine, Istanbul University, Istanbul, Turkey b c
a r t i c l e
i n f o
Article history: Received 8 July 2011 Revised 26 October 2011 Accepted 3 November 2011 Available online 10 January 2012 Keywords: Psychogenic nonepileptic seizures Epileptic seizures Personality disorders Psychiatric disorders
a b s t r a c t Identifying psychiatric disorders rather than psychiatric symptoms might help to distinguish patients with psychogenic nonepileptic seizures (PNES) from those with epileptic seizures (ES). Patients with PNES (n = 35), patients with ES (n = 35), and healthy controls (n = 37) were compared with respect to the prevalence of psychiatric disorders in this study. We tested the predictive power of having axis I psychiatric disorders, as well as personality disorders, in distinguishing ES from PNES. There was no significant difference between the patient groups in the prevalence of axis I psychiatric disorders. Personality disorders were more prevalent in the PNES group than in the ES group (P b 0.05). Having a personality disorder was the only predictor for the PNES group. Having a personality disorder seems to be a more significant predictor for PNES than having an axis I psychiatric disorder. Greater attention should be paid to personality disorders in the differentiation of PNES and ES and the provision of effective treatment. © 2011 Elsevier Inc. All rights reserved.
1. Introduction Although frequently seen in epilepsy centers, psychogenic nonepileptic seizures (PNES) are difficult to diagnose. This is due to the clinical manifestations common to both PNES and epileptic seizures (ES) [1,2]. Prolonged video-electroencephalographic monitoring is the gold standard for identifying PNES; however, it is costly and cannot be performed at all centers. Therefore, defining the clinical features of PNES is important to distinguish ES and PNES. Moreover, elucidating the clinical features of PNES may also help to identify the etiology of PNES and may affect treatment decisions. One of the known clinical features of PNES is comorbid psychopathological conditions, including anxiety disorders, affective disorders, posttraumatic stress disorders, dissociative disorders, somatoform disorders, and personality disorders [3]. However, psychiatric disorders such as mood and anxiety disorders and personality disorders are also common in patients with ES [4–7]. Studies exploring psychopathology in PNES and ES have focused mainly on common axis I psychiatric disorders such as depression and anxiety. Previous studies suggest that personality disorders are prevalent in patients with PNES and ES, and the presence of personality disorders is associated with poor prognosis, diminished quality of life, and increased resource use in both PNES and ES [4,8,9].
Despite multiple studies of personality disorders in patients with PNES and ES, it is difficult to interpret the results because of the different diagnostic tools used. The Minnesota Multiphasic Personality Inventory (MMPI), which provides dimensional classification of personality traits/psychopathological features, was widely used in previous studies. However, the DSM-IV-TR [10] is the current gold standard for diagnosing personality disorders and only little systematic research is available comparing the prevalence of DSM-IV-TR-based personality disorders between patients with PNES and ES. Studies indicate that cluster B personality disorders (i.e., antisocial, borderline, histrionic, and narcissistic) are the most common personality disorders in patients with PNES [8,9,11]. Borderline personality disorder (BPD) has been identified as the most dominant cluster B disorder in patients with PNES [9]. However, cluster C personality disorders (i.e., avoidant, dependent, obsessive–compulsive) are the most common personality disorders in patients with ES [4]. A higher prevalence of axis I psychiatric disorders and personality disorders has been demonstrated in both PNES and ES. However, the predictive power of these disorders to distinguish the two diseases remains unclear. Therefore, we aimed to compare their prevalence in patients with PNES, patients with ES, and healthy controls, and to test their power in predicting PNES. 2. Methods
⁎ Corresponding author at: Department of Epidemiology, Erasmus Medical Centre, PO Box 2040 3000 CA, Rotterdam, The Netherlands. Fax: + 31 10 70 44657. E-mail address: [email protected] (N. Direk). 1525-5050/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.yebeh.2011.11.013
The current study included all patients with PNES referred to the Epilepsy Unit of the Department of Neurology and the Department
N. Direk et al. / Epilepsy & Behavior 23 (2012) 138–141
of Psychiatry at the Istanbul School of Medicine between March 2006 and July 2008. Among the 42 eligible patients with PNES, 35 (71%) agreed to participate in the study. No age (P = 0.531) or sex (P = 0.567) differences were detected between participants and nonparticipants. Video-electroencephalography (video/EEG) with 32channel monitoring was used for all patients, stopping when one or more representative attacks recurred. EEG data were recorded from gold-disk scalp electrodes placed according to the extended International 10–20 system. During the video/EEG sessions, PNES occurred either spontaneously or were induced by usual activation procedures, including hyperventilation and intermittent photic stimulation, as well as verbally, but not by other suggestion techniques or intravenous practices [12]. PNES was defined as a noticeable, sudden change in behavior that was not accompanied by an electrophysiological ictal EEG seizure pattern [13]. Thirty-five age- and gender-matched patients with complex partial ES referred to the outpatient clinic between March 2006 and July 2008 were recruited for the study. The patients were grouped according to their seizure presentations as defined by International League Against Epilepsy criteria [14]. Age- and gender-matched healthy controls with no previous history of PNES and ES were selected from among hospital staff members who were known to be free of chronic diseases. Individuals below 18 and over 65, those with a serious/acute medical condition, those who required an urgent intervention, and those with whom it was not possible to conduct semistructured psychiatric interviews and detailed neurological examination focusing on the research questions were excluded. Informed consent was obtained from each participant before enrollment. The study protocol was approved by the local ethics committee. All video/EEG records, clinical histories of the participants, routine neurological examination findings, and (when necessary) neuroimaging findings were evaluated by two experienced neurologists (K.A., C.G.) for the complete clinical diagnosis. Following the first neurological examination (within the same week), a routine psychiatric examination was done. After this examination, a series of semistructured psychiatric interviews to diagnose patients for axis I psychiatric disorders and personality disorders was administered to each outpatient participant using the Structured Clinical Interview for DSM-IVTR Axis I disorders (SCID-I) [15] and the Structured Clinical Interview for DSM-III-R Axis II Disorders (SCID-II) [16]. Each diagnostic interview was conducted in two different sessions and lasted between 20 and 90 minutes depending on the patient's psychopathology and ability to answer the questions. Psychiatric examinations and SCIDs were conducted by a psychiatrist qualified to administer them (N.D.). Findings of psychiatric examinations and results of semistructural interviews were reviewed by two psychiatrists for the final decision (N.D., I.B.K.). Comparisons among the three groups for continuous variables were made using ANOVA. The χ 2 test was used for categorical variables. Prevalence rates of axis I psychiatric disorders and personality disorders were compared with multinomial logistic regression. An a priori power analysis was performed to detect the minimum number
139
of participants required to detect a significant difference. With a power of 0.90, a P value of 0.05, and an effect size of 0.5, the minimum number of participants required to detect a significant difference was 51, which indicates enough power to detect a reasonable difference. PNES and ES were both used as a dichotomous variable (0 = ES, 1 = PNES); therefore, a hierarchical logistic regression was performed to predict being in the PNES group. Independent variables were entered in three blocks. In the first block, years of education, marital status (0 = single, 1 = married), and duration of illness were entered. Presence of a personality disorder was entered in the second block. Finally, presence of an axis I psychiatric disorder was entered in the third block. Discrimination was calculated as the area under the receiver operator curve. SPSS Version 16 (SPSS Inc, Chicago, IL, USA) was used for statistical analyses. 3. Results Baseline characteristics of participants and comparisons are summarized in Table 1. The three groups were comparable in terms of sociodemographic variables. The prevalence of axis I psychiatric disorders was higher in patients with PNES or ES than in healthy controls (Table 2). The odds of having an axis I psychiatric disorder were statistically significantly higher in patients with PNES (odds ratio [OR] = 9.4, 95% confidence interval (CI) = 3.2–27.8, P b 0.001) as well as in patients with ES (OR = 7.3, 95% CI = 2.5–21.2, P b 0.001) compared with healthy controls. However, there was no significant difference between the groups in terms of the presence of axis I psychiatric disorders (OR = 1.3, 95% CI = 0.5–3.5, P = 0.615). The prevalence of personality disorders was higher in patients with PNES than either those with ES or healthy controls (Table 2). Patients with PNES or ES had higher odds of having personality disorders (OR = 18.5, 95% CI = 5.5–62.0, P b 0.001, and OR = 3.3, 95% CI = 1.0–10.8, P = 0.044, respectively) than healthy control subjects. Personality disorders were more frequent in patients with PNES (OR = 5.5, 95% CI = 2.0–15.5, P = 0.001) than patients with ES. Cluster B personality disorders were more prevalent in the PNES group than the ES group (OR = 11.6, 95% CI = 3.4–40.2, P b 0.001). There were no significant differences between the PNES and ES groups in terms of cluster A (P = 0.326) and cluster B (P = 0.065) personality disorders. The predictive power of the presence of axis I psychiatric disorders and personality disorders on the likelihood of being in the PNES group was tested with a hierarchical logistic regression. Adjustment for years of education, marital status, and duration of illness did not improve the estimates (χ²[3] = 3.5, P = 0.322). In the second block, the presence of any personality disorder produced a significant improvement in the estimates (χ²[1] = 12.3, P b 0.001), and only the presence of personality disorders predicted PNES. In the final block, the presence of axis I psychiatric disorders did not improve the estimates (χ²[1] = 0.2, P = 0.656) but the presence of a personality disorder remained a significant predictor. The individual effects of the
Table 1 Sociodemographic features and comparisons. Descriptive analyses
Age, years, mean (SD) Gender, female, n (%) Education, years, mean (SD) Marital status, married, n (%) Employment status, unemployed, n (%) Age at onset of disease, years, mean (SD) Duration of disease, years, mean (SD)
Inferential analyses
PNES (n = 35
ES (n = 35)
Control (n = 37)
Statistic
P
29.1 29 8.6 20 19 24.7 4.6
28.2 (8.3) 28 (80) 9.2 (3.8) 23 (65.7) 21(35) 21.9 (7.9) 6.3 (4.6)
28.4 (7.1) 29 (78.4) 9 (3.6) 25 (67.6) 20 (33.3) NA NA
F(2, 104) = 0.1 χ²(2) = 0.2 F(2, 104) = 0.2 χ²(2) = 0.9 χ²(4) = 0.6 T(68) = 1.5 T(68) = − 1.7
0.890 0.890 0.796 0.622 0.964 0.146 0.102
(9.2) (82.9) (3.5) (57.1) (31.7) (8.3) (4.2)
140
N. Direk et al. / Epilepsy & Behavior 23 (2012) 138–141
Table 2 Axis I psychiatric disorders and personality disorders in patient groups and healthy controls. n (%)
Axis I psychiatric disorders Any axis I disorder (current) Depressive disorders Major depressive disorder Dysthymic disorder Anxiety disorders Generalized anxiety disorder Panic disorder Posttraumatic stress disorder Obsessive–compulsive disorder Specific phobia Social phobia Anxiety disorder, NOSa Psychotic disorder, NOS Personality disorders Any personality disorder Cluster A Paranoid personality disorder Schizoid personality disorder Schizotypal personality disorder Cluster B Antisocial personality disorder Borderline personality disorder Histrionic personality disorder Narcissistic personality disorder Cluster C Avoidant personality disorder Dependent personality disorder Obsessive–compulsive personality disorder a
PNES (n = 35)
ES (n = 35)
Control (n = 37)
24 (68.6) 13 (37.1) 10 (28.6) 3 (8.6) 18 (51.4) 6 (17.1) 2 (5.7) 6 (17.1) 3 (8.6) 1 (2.9) 2 (5.7) 2 (5.7) 0
22 (62.9) 9 (25.7) 7 (20) 2 (5.7) 13 (37.1) 2 (5.7) 0 2 (5.7) 6 (17.1) 2 (5.7) 1 (2.9) 3 (8.6) 4 (11.4)
7 (18.9) 7 (18.9) 5 (13.5) 2 (5.7) 2 (5.4) 1 (2.9) 0 0 1 (2.7) 0 0 0 0
26 (74.3) 1 (2.9) 1 (2.9) 0 0 21 (60) 1 (2.9) 14 (40) 7 (20) 7 (20) 13 (37.1) 9 (25.7) 2 (5.7) 8 (22.9)
12 (34.3) 3 (8.6) 1 (2.9) 1 (2.9) 1 (2.9) 4 (11.4) 0 2 (5.7) 2 (5.7) 0 6 (17.1) 1 (2.9) 1 (2.9) 4 (11.4)
5 (13.5) 0 0 0 0 1 (2.7) 0 1 (2.7) 0 0 4 (10.8) 0 2 (5.4) 3 (8.1)
NOS, not otherwise specified.
predictors in each block are outlined in Table 3. The fit of the model was good, as indicated by the Hosmer–Lemeshow test (P = 0.277). The specifity of the final model was 71.4% and the sensitivity was 74.3%. Area under the ROC to discriminate the two disorders was 0.76 (SE = 0.06, 95% CI = 0.7–0.9), which indicates acceptable discrimination. 4. Discussion In this case–control study we found that axis I psychiatric disorders were more prevalent in patients with PNES or ES than in healthy controls. However, there was no significant difference between the patients with PNES and those with ES. The prevalence of personality
Table 3 Individual effects of predictors by hierarchical logistic regression.
Model 1 Education (years) Marital status (0 = single, 1 = married) Duration of illness (years) Model 2 Education (years) Marital status (0 = single, 1 = married) Duration of illness (years) Personality disorder Model 3 Education (years) Marital status (0 = single, 1 = married) Duration of illness (years) Personality disorder Axis I psychiatric disorder
OR
95% CI
P
0.9 0.8 0.9
0.8–1.1 0.3–2.3 0.8–1.0
0.448 0.726 0.132
0.9 0.4 0.9 6.9
0.8–1.1 0.1–1.5 0.8–1.1 2.2–22.1
0.521 0.194 0.312 0.001
0.9 0.5 0.9 7.1 1.3
0.8–1.1 0.1–1.6 0.8–1.1 2.2– 23.2 0.4–4.3
0.609 0.217 0.350 0.001 0.657
disorders was significantly higher in patients with PNES than in either those with ES or the healthy controls. Having a personality disorder was the only predictor of having PNES. Psychiatric disorders have frequently been reported in patients with PNES and ES [4,5,9,11,17]. The majority of previous studies exploring psychopathology in PNES and ES have focused on psychiatric symptoms rather than clinical diagnoses. However, those results are controversial because of the different measurement techniques and different samples used. Some found higher levels of depressive or anxiety symptoms in patients with PNES than patients with ES [18,19], whereas others found no difference [18,20–22]. The lack of structured interviews in these studies limits the clinical interpretability of the results. Studies with structured interviews are limited. In an earlier study, the prevalence of axis I psychiatric disorders based on a structured interview was 43% in patients with PNES and 30% in patients with ES [23]. In another study, 70% of patients with PNES and 57% of patients with ES had an axis I psychiatric disorder according to ICD-10, although the difference was not statistically significant. In that study, anxiety disorders were more common in patients with PNES than in those with ES [18]. Similarly, Binzer et al. have found that there is no significant difference in the prevalence of current axis I disorders between patients with recent-onset PNES and ES [24]. Major depression was the most common axis I psychiatric disorder in that study. Overall, these findings are consistent with our results. The lack of a significant difference between the PNES and the ES groups might have several explanations. First, it is known that frequencies of individual axis I psychiatric disorders such as dissociative disorders, posttraumatic stress disorders, and psychosis differ in patients with PNES and ES [4,9]. In the current study, numerical differences in individual axis I psychiatric disorders among groups were detected that may affect the overall frequency. However, we did not perform any significance tests for individual disorders as this was not the aim of the study. Second, both PNES and ES are disabling and stigmatizing. This may cause a high level of distress resulting in higher frequencies of psychiatric diseases in both groups. Our results show that both ES and PNES are associated with an increased prevalence of personality disorders. The prevalence of personality disorders in patients with ES was 34.3%, significantly higher than in healthy controls. In the ES group, the most common personality disorders were cluster C personality disorders, specifically obsessive–compulsive personality disorder. However, the difference between PNES and ES groups was not statistically significant. Seventy-four percent of patients in the PNES group had personality disorder in our study, and this prevalence was significantly higher than in patients with ES and healthy controls. Borderline personality disorder was the most common type within cluster B in patients with PNES. A high prevalence of DSM-IV-TR-based personality disorders, especially borderline personality disorder, has been reported previously in patients with PNES [11,25–29]. Cluster B personality disorders include dramatic, emotional, or erratic disorders (antisocial, borderline, histrionic, and narcissistic). The most common type, borderline personality disorder, is characterized by core symptom domains such as emotional dysregulation, impulse control, aggression, cognitive dysfunctions, and dissociative states. Patients with PNES and borderline personality disorder have some common traits. Higher prevalence rates of sexual trauma, posttraumatic stress disorder, dissociative disorders, somatoform disorders, depressive disorders, and suicide attempts have been reported in both conditions [9,29–31]. Other than common clinical comorbidities, several behavioral and emotional traits of borderline personality disorder have been observed in patients with PNES. These include anger problems and hostile coping styles [9]. These patients often have interpersonal problems which can also be observed in the doctor–patient relationship. Emotional instability, which means rapid shifts in intensity and type of emotion and dissociation, has also been previously reported
N. Direk et al. / Epilepsy & Behavior 23 (2012) 138–141
[8,17]. Overall, these findings suggest that borderline personality disorder might be an underlying etiological factor for PNES. In our study, we also showed that the presence of a personality disorder predicts having PNES only when education, marital status, duration of illness, and the presence of an axis I psychiatric disorder are included in the model hierarchically. In light of this finding, it can be said that exploring personality disorders may help to differentiate between patients with PNES and those with ES and to select the appropriate treatment. It is known that personality disorders worsen the prognosis of PNES and psychotherapies should be considered as the first-line treatment if personality disorder is the leading psychopathology [32,33]. The strengths of this study included having healthy controls and structured interviews. The structured interviews let us compare the prevalence rates of psychiatric diagnoses instead of relying on symptoms. However, the small sample did not allow comparison of individual disorders. Despite this, the prevalence of cluster B personality disorders was higher in patients with PNES, and the prevalence of cluster C personality disorders was higher in patients with ES. Additionally, this was a cross-sectional study and it cannot show causality between personality disorders and PNES. Another potential limitation of the current study is recall bias; that is, patients with PNES may report psychiatric complaints more than patients with ES and healthy controls or they may report them less because they may fear stigmatization or because they may strongly believe that it is a neurological condition rather than a psychiatric condition. It is known that interviewing techniques influence recall bias [34]. To overcome the recall bias, we used a series of interviews that consisted of only self-report questionnaires, but also semistructured interviews. In conclusion, psychiatric examinations seem to be effective in terms of diagnosing PNES and selecting treatment plans. Future prospective studies are needed to extend the current research by exploring individual personality disorders in greater detail. Contributors N.D. analyzed the data. N.D., I.B.K., and C.G. drafted the article. N.D., I.B.K., C.G., and K.A. provided critical revision of the article. All authors approved the final version for publication. Conflict of interest statement The authors report no conflict of interest. References [1] Benbadis SR. Allen Hauser W. An estimate of the prevalence of psychogenic nonepileptic seizures. Seizure 2000;9:280–1. [2] Francis P, Baker GA. Non-epileptic attack disorder (NEAD): a comprehensive review. Seizure 1999;8:53–61. [3] Kanner AM, Parra J, Frey M, Stebbins G, Pierre-Louis S, Iriarte J. Psychiatric and neurologic predictors of psychogenic pseudoseizure outcome. Neurology 1999;53:933–8. [4] Devinsky O. Psychiatric comorbidity in patients with epilepsy: implications for diagnosis and treatment. Epilepsy Behav 2003;4(Suppl. 4):S2–S10. [5] Swinkels WA, Kuyk J, van Dyck R, Spinhoven P. Psychiatric comorbidity in epilepsy. Epilepsy Behav 2005;7:37–50. [6] Hermann BP, Seidenberg M, Bell B. Psychiatric comorbidity in chronic epilepsy: identification, consequences, and treatment of major depression. Epilepsia 2000;41(Suppl. 2):S31–41.
141
[7] Rosenberg HJ, Rosenberg SD, Williamson PD, Wolford GL 2nd. A comparative study of trauma and posttraumatic stress disorder prevalence in epilepsy patients and psychogenic nonepileptic seizure patients. Epilepsia 2000;41:447–52. [8] Lacey C, Cook M, Salzberg M. The neurologist, psychogenic nonepileptic seizures, and borderline personality disorder. Epilepsy Behav 2007;11:492–8. [9] Bodde NM, Brooks JL, Baker GA, et al. Psychogenic non-epileptic seizures— definition, etiology, treatment and prognostic issues: a critical review. Seizure 2009;18:543–53. [10] Diagnostic criteria from DSM-IV-TR. Washington, DC: Am. Psychiatric Assoc.; 2000. [11] Galimberti CA, Ratti MT, Murelli R, Marchioni E, Manni R, Tartara A. Patients with psychogenic nonepileptic seizures, alone or epilepsy-associated, share a psychological profile distinct from that of epilepsy patients. J Neurol 2003;250:338–46. [12] Benbadis SR, Johnson K, Anthony K, et al. Induction of psychogenic nonepileptic seizures without placebo. Neurology 2000;55:1904–5. [13] Leis AA, Ross MA, Summers AK. Psychogenic seizures: ictal characteristics and diagnostic pitfalls. Neurology 1992;42:95–9. [14] Commission on Classification and Terminology of the International League Against Epilepsy. Proposal for revised classification of epilepsies and epileptic syndromes. Epilepsia 1989;30:389–99. [15] First MB, Williams JBW, Spitzer RL, Gibbon M. Structured Clinical Interview for DSM-IV Axis I Disorders, Clinician Version (SCID-CV). Washington, DC: Am. Psychiatric Press; 1996. [16] First MB, Gibbon M, Spitzer RL, Williams JBW, Benjamin LS. Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II). Washington, DC: Am. Psychiatric Press, Inc.; 1997. [17] Alsaadi TM, Marquez AV. Psychogenic nonepileptic seizures. Am Fam Physician 2005;72:849–56. [18] Krishnamoorthy ES, Brown RJ, Trimble MR. Personality and psychopathology in nonepileptic attack disorder and epilepsy: a prospective study. Epilepsy Behav 2001;2:418–22. [19] Owczarek K. Anxiety as a differential factor in epileptic versus psychogenic pseudoepileptic seizures. Epilepsy Res 2003;52:227–32. [20] Asmussen SB, Kirlin KA, Gale SD, Chung SS. Differences in self-reported depressive symptoms between patients with epileptic and psychogenic nonepileptic seizures. Seizure 2009;18:564–6. [21] Bewley J, Murphy PN, Mallows J, Baker GA. Does alexithymia differentiate between patients with nonepileptic seizures, patients with epilepsy, and nonpatient controls? Epilepsy Behav 2005;7:430–7. [22] Hixson JD, Balcer LJ, Glosser G, French JA. Fear sensitivity and the psychological profile of patients with psychogenic nonepileptic seizures. Epilepsy Behav 2006;9: 587–92. [23] Arnold LM, Privitera MD. Psychopathology and trauma in epileptic and psychogenic seizure patients. Psychosomatics 1996;37:438–43. [24] Binzer M, Stone J, Sharpe M. Recent onset pseudoseizures: clues to aetiology. Seizure 2004;13:146–55. [25] Harden CL, Hopp J, Ting TY, et al. Management issues for women with epilepsy— focus on pregnancy (an evidence-based review): I. Obstetrical complications and change in seizure frequency: Report of the Quality Standards Subcommittee and Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Epilepsia 2009;50:1229–36. [26] Bowman ES, Markand ON. Psychodynamics and psychiatric diagnoses of pseudoseizure subjects. Am J Psychiatry 1996;153:57–63. [27] Jawad SS, Jamil N, Clarke EJ, Lewis A, Whitecross S, Richens A. Psychiatric morbidity and psychodynamics of patients with convulsive pseudoseizures. Seizure 1995;4:201–6. [28] Bailles E, Pintor L, Torres X, Fernandez-Egea E, de Pablo J, Arroyo S. Psychiatric disease in patients with psychogenic non-epileptic seizures referred from an epilepsy unit in a general hospital. Actas Esp Psiquiatr 2004;32:76–81. [29] Harden CL, Jovine L, Burgut FT, Carey BT, Nikolov BG, Ferrando SJ. A comparison of personality disorder characteristics of patients with nonepileptic psychogenic pseudoseizures with those of patients with epilepsy. Epilepsy Behav 2009;14: 481–3. [30] Harden CL. Pseudoseizures and dissociative disorders: a common mechanism involving traumatic experiences. Seizure 1997;6:151–5. [31] Skodol AE, Gunderson JG, Pfohl B, Widiger TA, Livesley WJ, Siever LJ. The borderline diagnosis: I. Psychopathology, comorbidity, and personality structure. Biol Psychiatry 2002;51:936–50. [32] Bowman ES. Nonepileptic seizures: psychiatric framework, treatment, and outcome. Neurology 1999;53:S84–8. [33] Krumholz A. Nonepileptic seizures: diagnosis and management. Neurology 1999;53:S76–83. [34] Coughlin SS. Recall bias in epidemiologic studies. J Clin Epidemiol 1990;43:87–91.
Contents lists available at SciVerse ScienceDirect
Epilepsy & Behavior journal homepage: www.elsevier.com/locate/yebeh
Using personality disorders to distinguish between patients with psychogenic nonepileptic seizures and those with epileptic seizures Nese Direk a,⁎, Isin Baral Kulaksizoglu b, Kadriye Alpay c, Candan Gurses d a
Department of Epidemiology, Erasmus Medical Centre, Rotterdam, The Netherlands Department of Psychiatry, Istanbul School of Medicine, Istanbul University, Istanbul, Turkey Department of Neurology, Gebze Central Hospital, Kocaeli, Turkey d Department of Neurology, Istanbul School of Medicine, Istanbul University, Istanbul, Turkey b c
a r t i c l e
i n f o
Article history: Received 8 July 2011 Revised 26 October 2011 Accepted 3 November 2011 Available online 10 January 2012 Keywords: Psychogenic nonepileptic seizures Epileptic seizures Personality disorders Psychiatric disorders
a b s t r a c t Identifying psychiatric disorders rather than psychiatric symptoms might help to distinguish patients with psychogenic nonepileptic seizures (PNES) from those with epileptic seizures (ES). Patients with PNES (n = 35), patients with ES (n = 35), and healthy controls (n = 37) were compared with respect to the prevalence of psychiatric disorders in this study. We tested the predictive power of having axis I psychiatric disorders, as well as personality disorders, in distinguishing ES from PNES. There was no significant difference between the patient groups in the prevalence of axis I psychiatric disorders. Personality disorders were more prevalent in the PNES group than in the ES group (P b 0.05). Having a personality disorder was the only predictor for the PNES group. Having a personality disorder seems to be a more significant predictor for PNES than having an axis I psychiatric disorder. Greater attention should be paid to personality disorders in the differentiation of PNES and ES and the provision of effective treatment. © 2011 Elsevier Inc. All rights reserved.
1. Introduction Although frequently seen in epilepsy centers, psychogenic nonepileptic seizures (PNES) are difficult to diagnose. This is due to the clinical manifestations common to both PNES and epileptic seizures (ES) [1,2]. Prolonged video-electroencephalographic monitoring is the gold standard for identifying PNES; however, it is costly and cannot be performed at all centers. Therefore, defining the clinical features of PNES is important to distinguish ES and PNES. Moreover, elucidating the clinical features of PNES may also help to identify the etiology of PNES and may affect treatment decisions. One of the known clinical features of PNES is comorbid psychopathological conditions, including anxiety disorders, affective disorders, posttraumatic stress disorders, dissociative disorders, somatoform disorders, and personality disorders [3]. However, psychiatric disorders such as mood and anxiety disorders and personality disorders are also common in patients with ES [4–7]. Studies exploring psychopathology in PNES and ES have focused mainly on common axis I psychiatric disorders such as depression and anxiety. Previous studies suggest that personality disorders are prevalent in patients with PNES and ES, and the presence of personality disorders is associated with poor prognosis, diminished quality of life, and increased resource use in both PNES and ES [4,8,9].
Despite multiple studies of personality disorders in patients with PNES and ES, it is difficult to interpret the results because of the different diagnostic tools used. The Minnesota Multiphasic Personality Inventory (MMPI), which provides dimensional classification of personality traits/psychopathological features, was widely used in previous studies. However, the DSM-IV-TR [10] is the current gold standard for diagnosing personality disorders and only little systematic research is available comparing the prevalence of DSM-IV-TR-based personality disorders between patients with PNES and ES. Studies indicate that cluster B personality disorders (i.e., antisocial, borderline, histrionic, and narcissistic) are the most common personality disorders in patients with PNES [8,9,11]. Borderline personality disorder (BPD) has been identified as the most dominant cluster B disorder in patients with PNES [9]. However, cluster C personality disorders (i.e., avoidant, dependent, obsessive–compulsive) are the most common personality disorders in patients with ES [4]. A higher prevalence of axis I psychiatric disorders and personality disorders has been demonstrated in both PNES and ES. However, the predictive power of these disorders to distinguish the two diseases remains unclear. Therefore, we aimed to compare their prevalence in patients with PNES, patients with ES, and healthy controls, and to test their power in predicting PNES. 2. Methods
⁎ Corresponding author at: Department of Epidemiology, Erasmus Medical Centre, PO Box 2040 3000 CA, Rotterdam, The Netherlands. Fax: + 31 10 70 44657. E-mail address: [email protected] (N. Direk). 1525-5050/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.yebeh.2011.11.013
The current study included all patients with PNES referred to the Epilepsy Unit of the Department of Neurology and the Department
N. Direk et al. / Epilepsy & Behavior 23 (2012) 138–141
of Psychiatry at the Istanbul School of Medicine between March 2006 and July 2008. Among the 42 eligible patients with PNES, 35 (71%) agreed to participate in the study. No age (P = 0.531) or sex (P = 0.567) differences were detected between participants and nonparticipants. Video-electroencephalography (video/EEG) with 32channel monitoring was used for all patients, stopping when one or more representative attacks recurred. EEG data were recorded from gold-disk scalp electrodes placed according to the extended International 10–20 system. During the video/EEG sessions, PNES occurred either spontaneously or were induced by usual activation procedures, including hyperventilation and intermittent photic stimulation, as well as verbally, but not by other suggestion techniques or intravenous practices [12]. PNES was defined as a noticeable, sudden change in behavior that was not accompanied by an electrophysiological ictal EEG seizure pattern [13]. Thirty-five age- and gender-matched patients with complex partial ES referred to the outpatient clinic between March 2006 and July 2008 were recruited for the study. The patients were grouped according to their seizure presentations as defined by International League Against Epilepsy criteria [14]. Age- and gender-matched healthy controls with no previous history of PNES and ES were selected from among hospital staff members who were known to be free of chronic diseases. Individuals below 18 and over 65, those with a serious/acute medical condition, those who required an urgent intervention, and those with whom it was not possible to conduct semistructured psychiatric interviews and detailed neurological examination focusing on the research questions were excluded. Informed consent was obtained from each participant before enrollment. The study protocol was approved by the local ethics committee. All video/EEG records, clinical histories of the participants, routine neurological examination findings, and (when necessary) neuroimaging findings were evaluated by two experienced neurologists (K.A., C.G.) for the complete clinical diagnosis. Following the first neurological examination (within the same week), a routine psychiatric examination was done. After this examination, a series of semistructured psychiatric interviews to diagnose patients for axis I psychiatric disorders and personality disorders was administered to each outpatient participant using the Structured Clinical Interview for DSM-IVTR Axis I disorders (SCID-I) [15] and the Structured Clinical Interview for DSM-III-R Axis II Disorders (SCID-II) [16]. Each diagnostic interview was conducted in two different sessions and lasted between 20 and 90 minutes depending on the patient's psychopathology and ability to answer the questions. Psychiatric examinations and SCIDs were conducted by a psychiatrist qualified to administer them (N.D.). Findings of psychiatric examinations and results of semistructural interviews were reviewed by two psychiatrists for the final decision (N.D., I.B.K.). Comparisons among the three groups for continuous variables were made using ANOVA. The χ 2 test was used for categorical variables. Prevalence rates of axis I psychiatric disorders and personality disorders were compared with multinomial logistic regression. An a priori power analysis was performed to detect the minimum number
139
of participants required to detect a significant difference. With a power of 0.90, a P value of 0.05, and an effect size of 0.5, the minimum number of participants required to detect a significant difference was 51, which indicates enough power to detect a reasonable difference. PNES and ES were both used as a dichotomous variable (0 = ES, 1 = PNES); therefore, a hierarchical logistic regression was performed to predict being in the PNES group. Independent variables were entered in three blocks. In the first block, years of education, marital status (0 = single, 1 = married), and duration of illness were entered. Presence of a personality disorder was entered in the second block. Finally, presence of an axis I psychiatric disorder was entered in the third block. Discrimination was calculated as the area under the receiver operator curve. SPSS Version 16 (SPSS Inc, Chicago, IL, USA) was used for statistical analyses. 3. Results Baseline characteristics of participants and comparisons are summarized in Table 1. The three groups were comparable in terms of sociodemographic variables. The prevalence of axis I psychiatric disorders was higher in patients with PNES or ES than in healthy controls (Table 2). The odds of having an axis I psychiatric disorder were statistically significantly higher in patients with PNES (odds ratio [OR] = 9.4, 95% confidence interval (CI) = 3.2–27.8, P b 0.001) as well as in patients with ES (OR = 7.3, 95% CI = 2.5–21.2, P b 0.001) compared with healthy controls. However, there was no significant difference between the groups in terms of the presence of axis I psychiatric disorders (OR = 1.3, 95% CI = 0.5–3.5, P = 0.615). The prevalence of personality disorders was higher in patients with PNES than either those with ES or healthy controls (Table 2). Patients with PNES or ES had higher odds of having personality disorders (OR = 18.5, 95% CI = 5.5–62.0, P b 0.001, and OR = 3.3, 95% CI = 1.0–10.8, P = 0.044, respectively) than healthy control subjects. Personality disorders were more frequent in patients with PNES (OR = 5.5, 95% CI = 2.0–15.5, P = 0.001) than patients with ES. Cluster B personality disorders were more prevalent in the PNES group than the ES group (OR = 11.6, 95% CI = 3.4–40.2, P b 0.001). There were no significant differences between the PNES and ES groups in terms of cluster A (P = 0.326) and cluster B (P = 0.065) personality disorders. The predictive power of the presence of axis I psychiatric disorders and personality disorders on the likelihood of being in the PNES group was tested with a hierarchical logistic regression. Adjustment for years of education, marital status, and duration of illness did not improve the estimates (χ²[3] = 3.5, P = 0.322). In the second block, the presence of any personality disorder produced a significant improvement in the estimates (χ²[1] = 12.3, P b 0.001), and only the presence of personality disorders predicted PNES. In the final block, the presence of axis I psychiatric disorders did not improve the estimates (χ²[1] = 0.2, P = 0.656) but the presence of a personality disorder remained a significant predictor. The individual effects of the
Table 1 Sociodemographic features and comparisons. Descriptive analyses
Age, years, mean (SD) Gender, female, n (%) Education, years, mean (SD) Marital status, married, n (%) Employment status, unemployed, n (%) Age at onset of disease, years, mean (SD) Duration of disease, years, mean (SD)
Inferential analyses
PNES (n = 35
ES (n = 35)
Control (n = 37)
Statistic
P
29.1 29 8.6 20 19 24.7 4.6
28.2 (8.3) 28 (80) 9.2 (3.8) 23 (65.7) 21(35) 21.9 (7.9) 6.3 (4.6)
28.4 (7.1) 29 (78.4) 9 (3.6) 25 (67.6) 20 (33.3) NA NA
F(2, 104) = 0.1 χ²(2) = 0.2 F(2, 104) = 0.2 χ²(2) = 0.9 χ²(4) = 0.6 T(68) = 1.5 T(68) = − 1.7
0.890 0.890 0.796 0.622 0.964 0.146 0.102
(9.2) (82.9) (3.5) (57.1) (31.7) (8.3) (4.2)
140
N. Direk et al. / Epilepsy & Behavior 23 (2012) 138–141
Table 2 Axis I psychiatric disorders and personality disorders in patient groups and healthy controls. n (%)
Axis I psychiatric disorders Any axis I disorder (current) Depressive disorders Major depressive disorder Dysthymic disorder Anxiety disorders Generalized anxiety disorder Panic disorder Posttraumatic stress disorder Obsessive–compulsive disorder Specific phobia Social phobia Anxiety disorder, NOSa Psychotic disorder, NOS Personality disorders Any personality disorder Cluster A Paranoid personality disorder Schizoid personality disorder Schizotypal personality disorder Cluster B Antisocial personality disorder Borderline personality disorder Histrionic personality disorder Narcissistic personality disorder Cluster C Avoidant personality disorder Dependent personality disorder Obsessive–compulsive personality disorder a
PNES (n = 35)
ES (n = 35)
Control (n = 37)
24 (68.6) 13 (37.1) 10 (28.6) 3 (8.6) 18 (51.4) 6 (17.1) 2 (5.7) 6 (17.1) 3 (8.6) 1 (2.9) 2 (5.7) 2 (5.7) 0
22 (62.9) 9 (25.7) 7 (20) 2 (5.7) 13 (37.1) 2 (5.7) 0 2 (5.7) 6 (17.1) 2 (5.7) 1 (2.9) 3 (8.6) 4 (11.4)
7 (18.9) 7 (18.9) 5 (13.5) 2 (5.7) 2 (5.4) 1 (2.9) 0 0 1 (2.7) 0 0 0 0
26 (74.3) 1 (2.9) 1 (2.9) 0 0 21 (60) 1 (2.9) 14 (40) 7 (20) 7 (20) 13 (37.1) 9 (25.7) 2 (5.7) 8 (22.9)
12 (34.3) 3 (8.6) 1 (2.9) 1 (2.9) 1 (2.9) 4 (11.4) 0 2 (5.7) 2 (5.7) 0 6 (17.1) 1 (2.9) 1 (2.9) 4 (11.4)
5 (13.5) 0 0 0 0 1 (2.7) 0 1 (2.7) 0 0 4 (10.8) 0 2 (5.4) 3 (8.1)
NOS, not otherwise specified.
predictors in each block are outlined in Table 3. The fit of the model was good, as indicated by the Hosmer–Lemeshow test (P = 0.277). The specifity of the final model was 71.4% and the sensitivity was 74.3%. Area under the ROC to discriminate the two disorders was 0.76 (SE = 0.06, 95% CI = 0.7–0.9), which indicates acceptable discrimination. 4. Discussion In this case–control study we found that axis I psychiatric disorders were more prevalent in patients with PNES or ES than in healthy controls. However, there was no significant difference between the patients with PNES and those with ES. The prevalence of personality
Table 3 Individual effects of predictors by hierarchical logistic regression.
Model 1 Education (years) Marital status (0 = single, 1 = married) Duration of illness (years) Model 2 Education (years) Marital status (0 = single, 1 = married) Duration of illness (years) Personality disorder Model 3 Education (years) Marital status (0 = single, 1 = married) Duration of illness (years) Personality disorder Axis I psychiatric disorder
OR
95% CI
P
0.9 0.8 0.9
0.8–1.1 0.3–2.3 0.8–1.0
0.448 0.726 0.132
0.9 0.4 0.9 6.9
0.8–1.1 0.1–1.5 0.8–1.1 2.2–22.1
0.521 0.194 0.312 0.001
0.9 0.5 0.9 7.1 1.3
0.8–1.1 0.1–1.6 0.8–1.1 2.2– 23.2 0.4–4.3
0.609 0.217 0.350 0.001 0.657
disorders was significantly higher in patients with PNES than in either those with ES or the healthy controls. Having a personality disorder was the only predictor of having PNES. Psychiatric disorders have frequently been reported in patients with PNES and ES [4,5,9,11,17]. The majority of previous studies exploring psychopathology in PNES and ES have focused on psychiatric symptoms rather than clinical diagnoses. However, those results are controversial because of the different measurement techniques and different samples used. Some found higher levels of depressive or anxiety symptoms in patients with PNES than patients with ES [18,19], whereas others found no difference [18,20–22]. The lack of structured interviews in these studies limits the clinical interpretability of the results. Studies with structured interviews are limited. In an earlier study, the prevalence of axis I psychiatric disorders based on a structured interview was 43% in patients with PNES and 30% in patients with ES [23]. In another study, 70% of patients with PNES and 57% of patients with ES had an axis I psychiatric disorder according to ICD-10, although the difference was not statistically significant. In that study, anxiety disorders were more common in patients with PNES than in those with ES [18]. Similarly, Binzer et al. have found that there is no significant difference in the prevalence of current axis I disorders between patients with recent-onset PNES and ES [24]. Major depression was the most common axis I psychiatric disorder in that study. Overall, these findings are consistent with our results. The lack of a significant difference between the PNES and the ES groups might have several explanations. First, it is known that frequencies of individual axis I psychiatric disorders such as dissociative disorders, posttraumatic stress disorders, and psychosis differ in patients with PNES and ES [4,9]. In the current study, numerical differences in individual axis I psychiatric disorders among groups were detected that may affect the overall frequency. However, we did not perform any significance tests for individual disorders as this was not the aim of the study. Second, both PNES and ES are disabling and stigmatizing. This may cause a high level of distress resulting in higher frequencies of psychiatric diseases in both groups. Our results show that both ES and PNES are associated with an increased prevalence of personality disorders. The prevalence of personality disorders in patients with ES was 34.3%, significantly higher than in healthy controls. In the ES group, the most common personality disorders were cluster C personality disorders, specifically obsessive–compulsive personality disorder. However, the difference between PNES and ES groups was not statistically significant. Seventy-four percent of patients in the PNES group had personality disorder in our study, and this prevalence was significantly higher than in patients with ES and healthy controls. Borderline personality disorder was the most common type within cluster B in patients with PNES. A high prevalence of DSM-IV-TR-based personality disorders, especially borderline personality disorder, has been reported previously in patients with PNES [11,25–29]. Cluster B personality disorders include dramatic, emotional, or erratic disorders (antisocial, borderline, histrionic, and narcissistic). The most common type, borderline personality disorder, is characterized by core symptom domains such as emotional dysregulation, impulse control, aggression, cognitive dysfunctions, and dissociative states. Patients with PNES and borderline personality disorder have some common traits. Higher prevalence rates of sexual trauma, posttraumatic stress disorder, dissociative disorders, somatoform disorders, depressive disorders, and suicide attempts have been reported in both conditions [9,29–31]. Other than common clinical comorbidities, several behavioral and emotional traits of borderline personality disorder have been observed in patients with PNES. These include anger problems and hostile coping styles [9]. These patients often have interpersonal problems which can also be observed in the doctor–patient relationship. Emotional instability, which means rapid shifts in intensity and type of emotion and dissociation, has also been previously reported
N. Direk et al. / Epilepsy & Behavior 23 (2012) 138–141
[8,17]. Overall, these findings suggest that borderline personality disorder might be an underlying etiological factor for PNES. In our study, we also showed that the presence of a personality disorder predicts having PNES only when education, marital status, duration of illness, and the presence of an axis I psychiatric disorder are included in the model hierarchically. In light of this finding, it can be said that exploring personality disorders may help to differentiate between patients with PNES and those with ES and to select the appropriate treatment. It is known that personality disorders worsen the prognosis of PNES and psychotherapies should be considered as the first-line treatment if personality disorder is the leading psychopathology [32,33]. The strengths of this study included having healthy controls and structured interviews. The structured interviews let us compare the prevalence rates of psychiatric diagnoses instead of relying on symptoms. However, the small sample did not allow comparison of individual disorders. Despite this, the prevalence of cluster B personality disorders was higher in patients with PNES, and the prevalence of cluster C personality disorders was higher in patients with ES. Additionally, this was a cross-sectional study and it cannot show causality between personality disorders and PNES. Another potential limitation of the current study is recall bias; that is, patients with PNES may report psychiatric complaints more than patients with ES and healthy controls or they may report them less because they may fear stigmatization or because they may strongly believe that it is a neurological condition rather than a psychiatric condition. It is known that interviewing techniques influence recall bias [34]. To overcome the recall bias, we used a series of interviews that consisted of only self-report questionnaires, but also semistructured interviews. In conclusion, psychiatric examinations seem to be effective in terms of diagnosing PNES and selecting treatment plans. Future prospective studies are needed to extend the current research by exploring individual personality disorders in greater detail. Contributors N.D. analyzed the data. N.D., I.B.K., and C.G. drafted the article. N.D., I.B.K., C.G., and K.A. provided critical revision of the article. All authors approved the final version for publication. Conflict of interest statement The authors report no conflict of interest. References [1] Benbadis SR. Allen Hauser W. An estimate of the prevalence of psychogenic nonepileptic seizures. Seizure 2000;9:280–1. [2] Francis P, Baker GA. Non-epileptic attack disorder (NEAD): a comprehensive review. Seizure 1999;8:53–61. [3] Kanner AM, Parra J, Frey M, Stebbins G, Pierre-Louis S, Iriarte J. Psychiatric and neurologic predictors of psychogenic pseudoseizure outcome. Neurology 1999;53:933–8. [4] Devinsky O. Psychiatric comorbidity in patients with epilepsy: implications for diagnosis and treatment. Epilepsy Behav 2003;4(Suppl. 4):S2–S10. [5] Swinkels WA, Kuyk J, van Dyck R, Spinhoven P. Psychiatric comorbidity in epilepsy. Epilepsy Behav 2005;7:37–50. [6] Hermann BP, Seidenberg M, Bell B. Psychiatric comorbidity in chronic epilepsy: identification, consequences, and treatment of major depression. Epilepsia 2000;41(Suppl. 2):S31–41.
141
[7] Rosenberg HJ, Rosenberg SD, Williamson PD, Wolford GL 2nd. A comparative study of trauma and posttraumatic stress disorder prevalence in epilepsy patients and psychogenic nonepileptic seizure patients. Epilepsia 2000;41:447–52. [8] Lacey C, Cook M, Salzberg M. The neurologist, psychogenic nonepileptic seizures, and borderline personality disorder. Epilepsy Behav 2007;11:492–8. [9] Bodde NM, Brooks JL, Baker GA, et al. Psychogenic non-epileptic seizures— definition, etiology, treatment and prognostic issues: a critical review. Seizure 2009;18:543–53. [10] Diagnostic criteria from DSM-IV-TR. Washington, DC: Am. Psychiatric Assoc.; 2000. [11] Galimberti CA, Ratti MT, Murelli R, Marchioni E, Manni R, Tartara A. Patients with psychogenic nonepileptic seizures, alone or epilepsy-associated, share a psychological profile distinct from that of epilepsy patients. J Neurol 2003;250:338–46. [12] Benbadis SR, Johnson K, Anthony K, et al. Induction of psychogenic nonepileptic seizures without placebo. Neurology 2000;55:1904–5. [13] Leis AA, Ross MA, Summers AK. Psychogenic seizures: ictal characteristics and diagnostic pitfalls. Neurology 1992;42:95–9. [14] Commission on Classification and Terminology of the International League Against Epilepsy. Proposal for revised classification of epilepsies and epileptic syndromes. Epilepsia 1989;30:389–99. [15] First MB, Williams JBW, Spitzer RL, Gibbon M. Structured Clinical Interview for DSM-IV Axis I Disorders, Clinician Version (SCID-CV). Washington, DC: Am. Psychiatric Press; 1996. [16] First MB, Gibbon M, Spitzer RL, Williams JBW, Benjamin LS. Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II). Washington, DC: Am. Psychiatric Press, Inc.; 1997. [17] Alsaadi TM, Marquez AV. Psychogenic nonepileptic seizures. Am Fam Physician 2005;72:849–56. [18] Krishnamoorthy ES, Brown RJ, Trimble MR. Personality and psychopathology in nonepileptic attack disorder and epilepsy: a prospective study. Epilepsy Behav 2001;2:418–22. [19] Owczarek K. Anxiety as a differential factor in epileptic versus psychogenic pseudoepileptic seizures. Epilepsy Res 2003;52:227–32. [20] Asmussen SB, Kirlin KA, Gale SD, Chung SS. Differences in self-reported depressive symptoms between patients with epileptic and psychogenic nonepileptic seizures. Seizure 2009;18:564–6. [21] Bewley J, Murphy PN, Mallows J, Baker GA. Does alexithymia differentiate between patients with nonepileptic seizures, patients with epilepsy, and nonpatient controls? Epilepsy Behav 2005;7:430–7. [22] Hixson JD, Balcer LJ, Glosser G, French JA. Fear sensitivity and the psychological profile of patients with psychogenic nonepileptic seizures. Epilepsy Behav 2006;9: 587–92. [23] Arnold LM, Privitera MD. Psychopathology and trauma in epileptic and psychogenic seizure patients. Psychosomatics 1996;37:438–43. [24] Binzer M, Stone J, Sharpe M. Recent onset pseudoseizures: clues to aetiology. Seizure 2004;13:146–55. [25] Harden CL, Hopp J, Ting TY, et al. Management issues for women with epilepsy— focus on pregnancy (an evidence-based review): I. Obstetrical complications and change in seizure frequency: Report of the Quality Standards Subcommittee and Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Epilepsia 2009;50:1229–36. [26] Bowman ES, Markand ON. Psychodynamics and psychiatric diagnoses of pseudoseizure subjects. Am J Psychiatry 1996;153:57–63. [27] Jawad SS, Jamil N, Clarke EJ, Lewis A, Whitecross S, Richens A. Psychiatric morbidity and psychodynamics of patients with convulsive pseudoseizures. Seizure 1995;4:201–6. [28] Bailles E, Pintor L, Torres X, Fernandez-Egea E, de Pablo J, Arroyo S. Psychiatric disease in patients with psychogenic non-epileptic seizures referred from an epilepsy unit in a general hospital. Actas Esp Psiquiatr 2004;32:76–81. [29] Harden CL, Jovine L, Burgut FT, Carey BT, Nikolov BG, Ferrando SJ. A comparison of personality disorder characteristics of patients with nonepileptic psychogenic pseudoseizures with those of patients with epilepsy. Epilepsy Behav 2009;14: 481–3. [30] Harden CL. Pseudoseizures and dissociative disorders: a common mechanism involving traumatic experiences. Seizure 1997;6:151–5. [31] Skodol AE, Gunderson JG, Pfohl B, Widiger TA, Livesley WJ, Siever LJ. The borderline diagnosis: I. Psychopathology, comorbidity, and personality structure. Biol Psychiatry 2002;51:936–50. [32] Bowman ES. Nonepileptic seizures: psychiatric framework, treatment, and outcome. Neurology 1999;53:S84–8. [33] Krumholz A. Nonepileptic seizures: diagnosis and management. Neurology 1999;53:S76–83. [34] Coughlin SS. Recall bias in epidemiologic studies. J Clin Epidemiol 1990;43:87–91.