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Overlap between dissociation and other psychological characteristics in patients with psychogenic nonepileptic seizures
Epilepsy & Behavior 34 (2014) 47–49
Contents lists available at ScienceDirect
Epilepsy & Behavior journal homepage: www.elsevier.com/locate/yebeh
Brief Communication
Overlap between dissociation and other psychological characteristics in patients with psychogenic nonepileptic seizures Matthew L. Cohen a,⁎, S. Marc Testa a,b, Jennifer M. Pritchard b, Jingkun Zhu c, Jennifer L. Hopp b a b c
VA Maryland Healthcare System, Baltimore VA Medical Center, 10 N. Greene St., MH/116, Baltimore, MD, USA University of Maryland School of Medicine, Department of Neurology, 110 S. Paca St., Baltimore, MD, USA University of Maryland School of Medicine, Department of Epidemiology and Public Health, 660 W. Redwood St., Baltimore, MD, USA
a r t i c l e
i n f o
Article history: Received 24 January 2014 Revised 25 February 2014 Accepted 2 March 2014 Available online 28 March 2014 Keywords: Psychogenic nonepileptic seizures Dissociation Dissociative seizures
a b s t r a c t Patients with psychogenic nonepileptic seizures (PNES) often report symptoms of dissociation. However, it is unclear how these symptoms relate to psychotherapeutic treatment, for example, with cognitive-behavioral therapy (CBT). Here, we investigated the degree of overlap between symptoms of dissociation and other psychiatric features that are more traditional targets for CBT. We used a hierarchical linear regression to measure the variance associated with dissociative symptoms (as assessed by the Dissociative Experiences Scale — DES) among 46 individuals with PNESs. The regression predictor variables are indices of participants' self-rated mood, self-efficacy, quality of life, locus of control, and life outlook (e.g., optimism). Results revealed that 70.2% of the variance associated with DES score was explained by psychological distress and locus of control. The other factors examined did not make a significant contribution to the regression model. These results suggest that traditional CBT targets – mood symptoms, mood distress, and dysfunctional beliefs about locus of control – overlap substantially with self-reported dissociative symptoms. Published by Elsevier Inc.
1. Introduction Patients with psychogenic nonepileptic seizures (PNESs) often report numerous dissociative symptoms [1]. However, these symptoms are abstract and may therefore be difficult to target psychotherapeutically. Cognitive behavioral therapy (CBT) that focuses on anxiety, depression, and illness behavior is emerging as an efficacious intervention to diminish seizure frequency and improve functioning among individuals with PNESs [2–5]. However, of the treatment studies and protocols developed to target PNES behavior, dissociative symptoms are rarely mentioned and are not treated directly [3,4,6]. Studies of both healthy and psychiatric patient populations reveal strong relationships between dissociative symptoms and other psychological features such as anxiety and depression [7–9]. A similar understanding among patients with PNESs is growing [10]. As research continues to assess the efficacy of CBT for PNESs, it will be important to clarify the nature of dissociation among individuals with PNESs and delineate CBT targets more precisely. Accordingly, the present
⁎ Corresponding author at: Meyer 218, The Johns Hopkins Hospital, 600 North Wolfe St., Baltimore, MD 21287, USA. Tel.: +1 410 502 6338; fax: +1 410 955 0504. E-mail addresses: [email protected] (M.L. Cohen), [email protected] (S.M. Testa), [email protected] (J.M. Pritchard), [email protected] (J. Zhu), [email protected] (J.L. Hopp).
http://dx.doi.org/10.1016/j.yebeh.2014.03.001 1525-5050/Published by Elsevier Inc.
investigation aimed to better understand and describe more concrete correlates of the dissociative experiences endorsed by PNES patients to better guide treatment with psychotherapy. 2. Methods Participants were 46 patients with PNESs, seen consecutively at the University of Maryland Epilepsy Center from 2006 to 2013, who provided written informed consent in accordance with the Declaration of Helsinki and as approved by the Institutional Review Board at the University of Maryland School of Medicine. Eligible participants had a well-established diagnosis of PNESs, confirmed by video-EEG monitoring that captured typical events, and without evidence of coexisting epileptic seizures. The participants were at least 18 years old and had a Mini-Mental State Examination — MMSE [11] score greater than 24. Relevant demographic and clinical variables are shown in Table 1 but are detailed elsewhere [12]. The current study used regression models to understand the multivariate relationships between dissociative symptoms and other psychological variables. Dissociative symptoms were assessed with the Dissociative Experiences Scale — DES [13]. This measure is comprised of 28 descriptions of dissociative experiences, and the participants indicate how often each experience occurs (0–100%). The dependent variable was the mean DES score. A mean score greater than 30 is typically interpreted as abnormal. This measure is commonly used to
48
M.L. Cohen et al. / Epilepsy & Behavior 34 (2014) 47–49
Table 1 Patient demographic and clinical variables.
Table 3 Hierarchical linear regression.
Age Education MMSE Time to diagnosis (approx. weeks) PNES frequency (approx. seizures/month) Sex (% female) Married (%) Employed (%) Disabled (%)
Mean
SD
41.8 14.2 29.2 101.6 15.1 86.0 47.8 41.3 17.4
14.8 2.8 1.3 285.2 24.6
assess symptoms of dissociation in PNES patients [1,10] and has good psychometric properties [14,15], including convergent validity with other measures (combined effect size: d = 1.82) [17,18]. Independent predictors used in the model (Table 2) were derived from measures of mood, self-efficacy, health-related quality of life, and life outlook (comprised of measures of optimism, locus of control, and mutuality). These included the Brief Symptom Inventory — 18 [17], Beck Anxiety Inventory [18], Beck Depression Inventory — 2nd ed. [19], Lorig SelfEfficacy Scale [20], SF-12 version 2 [21], Life Orientation Test [22], Multidimensional Health Locus of Control [23], and Mutuality assessment [26]. Predictors derived from these measures were entered into a stepwise multiple regression predicting DES average score. Predictors were grouped into blocks by test or domain and entered into the regression based on correlation with DES score (higher correlations entered earlier). 3. Results and discussion Eight participants (17%) scored above the typical cutoff on the DES. Each of the regression models (steps) was significant (p ≤ .01), but only two of the steps were associated with a significant change in R2 (Table 3). The steps associated with the highest R2 (i.e., explained the highest variance of DES mean score) were mood distress (BSI scores) and locus of control. Specifically, higher levels of dissociative symptoms were predicted by greater distress (particularly relating to depression and somatic concerns), a stronger perceived control by others, and a weaker perceived control by doctors. Mood symptoms (i.e., BDI-2 and BAI scores) were significantly correlated with DES
Predictor
DES mean score
β
ΔR2 Step 1: Mood distress BSI: somatic BSI: depression BSI: anxiety Step 2: Mood symptoms BDI: somatic-performance BDI: cognitive–affective BAI: somatic BAI: cognitive Step 3: Optimism LOTR total score Step 4: Locus of control LOC: chance LOC: powerful others LOC: internal LOC: doctors Step 5: Health-related quality of life SF-12: physical SF-12: mental Step 6: Health-related quality of life Lorig: health Lorig: ADL Lorig: hobby Lorig: manage Lorig: exercise Step 7: Mutuality Mutuality total score Total R2 n
.530⁎⁎⁎
.374⁎ .496⁎ −.045
.049 .342 −.454 .146 .193 .012 .172⁎
−.205 .076 .312⁎ .188 −.321⁎
.012 −.003 .219 .050 −.298 .307 .294 .292 .172 .009 .163 .833 46
⁎ p b .05. ⁎⁎ p b .01. ⁎⁎⁎ p b .001.
score (rs = .503–.605), but not as strongly as mood distress scores (rs = .542–.624), and did not remain significant after accounting for the latter. Together, the mood distress and locus of control scores accounted for 70.2% of the variance in DES average score, and all of the variables from all steps accounted for 83.3% of the variance. The treatment of PNESs has lagged behind the treatment of other psychiatric disorders, perhaps because dissociative symptoms make PNES events seem enigmatic or different from other functional
Table 2 Regression predictors. Measure and reference
Domain
Regression predictors
Brief Symptom Inventory — 18
Psychological distress
Beck Anxiety Inventory
Symptoms of anxiety
Beck Depression Inventory — 2nd ed.
Symptoms of depression
Self-efficacy
Lorig Self-Efficacy Scaleb
Confidence in managing chronic disease
QoL
SF-12 version 2c
Self-rating of well-being
Life outlook
Life Orientation Test — Revised Multidimensional Health Locus of Control
Optimism Locus of control attributed to various sources
Mutuality
Perceived relationship with a spouse or close family member involved in his/her care
(a) Somatization (b) Depression (c) Anxiety (d) Cognitive (e) Somatic (f) Cognitive-affective subscale (g) Somatic-performance subscale (h) Managing disease (i) Managing symptoms (j) Doing chores (k) Exercising (l) Participating in social activities (m) Physical health (n) Mental health (o) Total score (p) Self (q) Powerful others (r) Chance (s) Doctors (t) Total score
Mood
a b c
a
The BSI-18 was included in addition to the BAI and BDI-2 because it assesses patient's distress related to mental health symptoms, which may be distinct from the symptoms themselves. The Lorig scale was modified in our study from the standard 10-point scale to a shorter 5-point scale. QoL = quality of life.
M.L. Cohen et al. / Epilepsy & Behavior 34 (2014) 47–49
symptoms. However, the current results demonstrate that dissociative symptoms overlap strongly with mood symptoms and emotional distress, as well as certain beliefs about locus of control. Dissociation may be a unique entity, but our results indicate that more commonplace psychiatric features explain the majority of the variance of self-reported dissociative symptoms in patients with PNESs. The current results do not provide any guidance about how dissociative symptoms may resolve with treatment of mood symptoms or locus of control beliefs. The extant literature, however, suggests that they may not. One study found that after CBT, the average DES score among participants remained stable despite reduction in seizure frequency, fewer symptoms of depression and anxiety, fewer somatic complaints, improved quality of life, and improved psychosocial functioning [3]. This raises the question of whether dissociative symptoms are meaningful. Our data, as well as those of LaFrance et al. [3], suggest that dissociative symptoms are not independently related to quality of life. Together, these findings indicate that dissociative symptoms may not impact one's overall level of functioning independent of other factors. Similar to the perspective of Schmutz [25], our findings indicate that the reported dissociative experiences of PNESs are not necessarily mysterious but may overlap with the symptoms of other psychiatric conditions. Moreover, symptoms of PNESs may not be distinct from other functional neurological disorders [12]. Instead, PNESs, as well as other functional neurologic symptoms, may reflect a common underlying psychiatric morbidity. The present research supports this view, in part, by demonstrating that the majority of variance in dissociative experiences overlaps with more commonplace symptoms and beliefs that have been treated successfully with CBT. Future research is needed to determine if a similar pattern exists in other manifestations of functional neurologic symptoms. A potential limitation of this study is that we did not analyze subgroups of patients, for example, based on DES score or history of trauma, the latter of which is related both to PNESs and to symptoms of dissociation [26]. Patients with PNESs are certainly not a homogeneous group: perhaps, dissociation is not a core feature for all patients with PNESs, and dissociation may not be the only mechanism of altered consciousness in PNESs [27]. The present investigation suggests that for the average patient with PNESs who is a good candidate for CBT, dissociative symptoms do not necessarily contraindicate traditional CBT, as these symptoms strongly overlap with mood symptoms, mood distress, and beliefs about locus of control. Conflicts of interest The authors declare that there are no conflicts of interest. References [1] Goldstein LH, Drew C, Mellers J, Mitchell-O'Malley S, Oakley DA. Dissociation, hypnotizability, coping styles and health locus of control: characteristics of pseudoseizure patients. Seizure 2000;9:314–22.
49
[2] Lesser RP. Treatment and outcome of psychogenic nonepileptic seizures. Epilepsy Curr 2003;3:198. [3] LaFrance Jr WC, Miller IW, Ryan CE, Blum AS, Solomon DA, Kelley JE, et al. Cognitive behavioral therapy for psychogenic nonepileptic seizures. Epilepsy Behav 2009;14: 591–6. [4] Goldstein L, Chalder T, Chigwedere C, Khondoker M, Moriarty J, Toone B, et al. Cognitive-behavioral therapy for psychogenic nonepileptic seizures: a pilot RCT. Neurology 2010;74:1986–94. [5] Hopp JL, LaFrance Jr WC. Cognitive behavioral therapy for psychogenic neurological disorders. Neurologist 2012;18:364–72. [6] Rusch MD, Morris GL, Allen L, Lathrop L. Psychological treatment of nonepileptic events. Epilepsy Behav 2001;2:277–83. [7] Gómez-Pérez L, López-Martínez AE, Asmundson GJG. Predictors of trait dissociation and peritraumatic dissociation induced via cold pressor. Psychiatry Res 2013;210:274–80. [8] Simeon D, Riggio-Rosen A, Guralnik O, Knutelska M, Nelson D. Depersonalization disorder: dissociation and affect. J Trauma Dissociation 2003;4:63–76. [9] Boysan M, Goldsmith RE, Çavuş H, Kayri M, Keskin S. Relations among anxiety, depression, and dissociative symptoms: the influence of abuse subtype. J Trauma Dissociation 2009;10:83–101. [10] Reuber M, House AO, Pukrop R, Bauer J, Elger CE. Somatization, dissociation and general psychopathology in patients with psychogenic non-epileptic seizures. Epilepsy Res 2003;57:159–67. [11] Folstein MF, Folstein SE, McHugh PR. “Mini-mental state”: a practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12: 189–98. [12] Hopp JL, Anderson KE, Krumholz A, Gruber-Baldini AL, Shulman LM. Psychogenic seizures and psychogenic movement disorders: are they the same patients? Epilepsy Behav 2012;25:666–9. [13] Bernstein EM, Putnam FW. Development, reliability, and validity of a dissociation scale. J Nerv Ment Dis 1986;174:727–35. [14] Carlson EB, Putnam FW. An update on the dissociative experiences scale. Dissociation: progress in the dissociative disorders; 1993. [15] Frischholz EJ, Braun BG, Sachs RG, Hopkins L. The Dissociative Experiences Scale: further replication and validation. Dissociation: progress in the dissociative disorders; 1990. [16] van Ijzendoorn MH, Schuengel C. The measurement of dissociation in normal and clinical populations: meta-analytic validation of the Dissociative Experiences Scale (DES). Child Psychol Rev 1996;16:365–82. [17] Derogatis LR. BSI 18, Brief Symptom Inventory 18: administration, scoring and procedures manual. NCS Pearson, Incorporated; 2001. [18] Beck AT, Epstein N, Brown G, Steer RA. An inventory for measuring clinical anxiety: psychometric properties. J Consult Clin Psychol 1988;56:893. [19] Beck AT, Steer RA, Brown GK. Beck Depression Inventory—II (BDI-II). San Antonio: Psychological Corporation; 1996. [20] Lorig K, Stewart A, Ritter P, González V. Outcome measures for health education and other health care interventions; 1996. [21] Ware JE, Kosinski M, Keller SD. SF-12: how to score the SF-12 physical and mental health summary scales. Health Institute, New England Medical Center; 1995. [22] Scheier MF, Carver CS, Bridges MW. Distinguishing optimism from neuroticism (and trait anxiety, self-mastery, and self-esteem): a reevaluation of the Life Orientation Test. J Pers Soc Psychol 1994;67:1063. [23] Wallston KA, Stein MJ, Smith CA. Form C of the MHLC scales: a condition-specific measure of locus of control. J Pers Assess 1994;63:534–53. [24] Archbold PG, Stewart BJ, Greenlick MR, Harvath T. Mutuality and preparedness as predictors of caregiver role strain. Res Nurs Health 1990;13:375–84. [25] Schmutz M. Dissociative seizures—a critical review and perspective. Epilepsy Behav 2013;29(3):449–56. [26] Fiszman A, Alves-Leon SV, Nunes RG, D'Andrea I, Figueira I. Traumatic events and posttraumatic stress disorder in patients with psychogenic nonepileptic seizures: a critical review. Epilepsy Behav 2004;5:818–25. [27] Roberts NA, Reuber M. Alterations of consciousness in psychogenic nonepileptic seizures: emotion, emotion regulation and dissociation. Epilepsy Behav 2014;30:43–9.
Contents lists available at ScienceDirect
Epilepsy & Behavior journal homepage: www.elsevier.com/locate/yebeh
Brief Communication
Overlap between dissociation and other psychological characteristics in patients with psychogenic nonepileptic seizures Matthew L. Cohen a,⁎, S. Marc Testa a,b, Jennifer M. Pritchard b, Jingkun Zhu c, Jennifer L. Hopp b a b c
VA Maryland Healthcare System, Baltimore VA Medical Center, 10 N. Greene St., MH/116, Baltimore, MD, USA University of Maryland School of Medicine, Department of Neurology, 110 S. Paca St., Baltimore, MD, USA University of Maryland School of Medicine, Department of Epidemiology and Public Health, 660 W. Redwood St., Baltimore, MD, USA
a r t i c l e
i n f o
Article history: Received 24 January 2014 Revised 25 February 2014 Accepted 2 March 2014 Available online 28 March 2014 Keywords: Psychogenic nonepileptic seizures Dissociation Dissociative seizures
a b s t r a c t Patients with psychogenic nonepileptic seizures (PNES) often report symptoms of dissociation. However, it is unclear how these symptoms relate to psychotherapeutic treatment, for example, with cognitive-behavioral therapy (CBT). Here, we investigated the degree of overlap between symptoms of dissociation and other psychiatric features that are more traditional targets for CBT. We used a hierarchical linear regression to measure the variance associated with dissociative symptoms (as assessed by the Dissociative Experiences Scale — DES) among 46 individuals with PNESs. The regression predictor variables are indices of participants' self-rated mood, self-efficacy, quality of life, locus of control, and life outlook (e.g., optimism). Results revealed that 70.2% of the variance associated with DES score was explained by psychological distress and locus of control. The other factors examined did not make a significant contribution to the regression model. These results suggest that traditional CBT targets – mood symptoms, mood distress, and dysfunctional beliefs about locus of control – overlap substantially with self-reported dissociative symptoms. Published by Elsevier Inc.
1. Introduction Patients with psychogenic nonepileptic seizures (PNESs) often report numerous dissociative symptoms [1]. However, these symptoms are abstract and may therefore be difficult to target psychotherapeutically. Cognitive behavioral therapy (CBT) that focuses on anxiety, depression, and illness behavior is emerging as an efficacious intervention to diminish seizure frequency and improve functioning among individuals with PNESs [2–5]. However, of the treatment studies and protocols developed to target PNES behavior, dissociative symptoms are rarely mentioned and are not treated directly [3,4,6]. Studies of both healthy and psychiatric patient populations reveal strong relationships between dissociative symptoms and other psychological features such as anxiety and depression [7–9]. A similar understanding among patients with PNESs is growing [10]. As research continues to assess the efficacy of CBT for PNESs, it will be important to clarify the nature of dissociation among individuals with PNESs and delineate CBT targets more precisely. Accordingly, the present
⁎ Corresponding author at: Meyer 218, The Johns Hopkins Hospital, 600 North Wolfe St., Baltimore, MD 21287, USA. Tel.: +1 410 502 6338; fax: +1 410 955 0504. E-mail addresses: [email protected] (M.L. Cohen), [email protected] (S.M. Testa), [email protected] (J.M. Pritchard), [email protected] (J. Zhu), [email protected] (J.L. Hopp).
http://dx.doi.org/10.1016/j.yebeh.2014.03.001 1525-5050/Published by Elsevier Inc.
investigation aimed to better understand and describe more concrete correlates of the dissociative experiences endorsed by PNES patients to better guide treatment with psychotherapy. 2. Methods Participants were 46 patients with PNESs, seen consecutively at the University of Maryland Epilepsy Center from 2006 to 2013, who provided written informed consent in accordance with the Declaration of Helsinki and as approved by the Institutional Review Board at the University of Maryland School of Medicine. Eligible participants had a well-established diagnosis of PNESs, confirmed by video-EEG monitoring that captured typical events, and without evidence of coexisting epileptic seizures. The participants were at least 18 years old and had a Mini-Mental State Examination — MMSE [11] score greater than 24. Relevant demographic and clinical variables are shown in Table 1 but are detailed elsewhere [12]. The current study used regression models to understand the multivariate relationships between dissociative symptoms and other psychological variables. Dissociative symptoms were assessed with the Dissociative Experiences Scale — DES [13]. This measure is comprised of 28 descriptions of dissociative experiences, and the participants indicate how often each experience occurs (0–100%). The dependent variable was the mean DES score. A mean score greater than 30 is typically interpreted as abnormal. This measure is commonly used to
48
M.L. Cohen et al. / Epilepsy & Behavior 34 (2014) 47–49
Table 1 Patient demographic and clinical variables.
Table 3 Hierarchical linear regression.
Age Education MMSE Time to diagnosis (approx. weeks) PNES frequency (approx. seizures/month) Sex (% female) Married (%) Employed (%) Disabled (%)
Mean
SD
41.8 14.2 29.2 101.6 15.1 86.0 47.8 41.3 17.4
14.8 2.8 1.3 285.2 24.6
assess symptoms of dissociation in PNES patients [1,10] and has good psychometric properties [14,15], including convergent validity with other measures (combined effect size: d = 1.82) [17,18]. Independent predictors used in the model (Table 2) were derived from measures of mood, self-efficacy, health-related quality of life, and life outlook (comprised of measures of optimism, locus of control, and mutuality). These included the Brief Symptom Inventory — 18 [17], Beck Anxiety Inventory [18], Beck Depression Inventory — 2nd ed. [19], Lorig SelfEfficacy Scale [20], SF-12 version 2 [21], Life Orientation Test [22], Multidimensional Health Locus of Control [23], and Mutuality assessment [26]. Predictors derived from these measures were entered into a stepwise multiple regression predicting DES average score. Predictors were grouped into blocks by test or domain and entered into the regression based on correlation with DES score (higher correlations entered earlier). 3. Results and discussion Eight participants (17%) scored above the typical cutoff on the DES. Each of the regression models (steps) was significant (p ≤ .01), but only two of the steps were associated with a significant change in R2 (Table 3). The steps associated with the highest R2 (i.e., explained the highest variance of DES mean score) were mood distress (BSI scores) and locus of control. Specifically, higher levels of dissociative symptoms were predicted by greater distress (particularly relating to depression and somatic concerns), a stronger perceived control by others, and a weaker perceived control by doctors. Mood symptoms (i.e., BDI-2 and BAI scores) were significantly correlated with DES
Predictor
DES mean score
β
ΔR2 Step 1: Mood distress BSI: somatic BSI: depression BSI: anxiety Step 2: Mood symptoms BDI: somatic-performance BDI: cognitive–affective BAI: somatic BAI: cognitive Step 3: Optimism LOTR total score Step 4: Locus of control LOC: chance LOC: powerful others LOC: internal LOC: doctors Step 5: Health-related quality of life SF-12: physical SF-12: mental Step 6: Health-related quality of life Lorig: health Lorig: ADL Lorig: hobby Lorig: manage Lorig: exercise Step 7: Mutuality Mutuality total score Total R2 n
.530⁎⁎⁎
.374⁎ .496⁎ −.045
.049 .342 −.454 .146 .193 .012 .172⁎
−.205 .076 .312⁎ .188 −.321⁎
.012 −.003 .219 .050 −.298 .307 .294 .292 .172 .009 .163 .833 46
⁎ p b .05. ⁎⁎ p b .01. ⁎⁎⁎ p b .001.
score (rs = .503–.605), but not as strongly as mood distress scores (rs = .542–.624), and did not remain significant after accounting for the latter. Together, the mood distress and locus of control scores accounted for 70.2% of the variance in DES average score, and all of the variables from all steps accounted for 83.3% of the variance. The treatment of PNESs has lagged behind the treatment of other psychiatric disorders, perhaps because dissociative symptoms make PNES events seem enigmatic or different from other functional
Table 2 Regression predictors. Measure and reference
Domain
Regression predictors
Brief Symptom Inventory — 18
Psychological distress
Beck Anxiety Inventory
Symptoms of anxiety
Beck Depression Inventory — 2nd ed.
Symptoms of depression
Self-efficacy
Lorig Self-Efficacy Scaleb
Confidence in managing chronic disease
QoL
SF-12 version 2c
Self-rating of well-being
Life outlook
Life Orientation Test — Revised Multidimensional Health Locus of Control
Optimism Locus of control attributed to various sources
Mutuality
Perceived relationship with a spouse or close family member involved in his/her care
(a) Somatization (b) Depression (c) Anxiety (d) Cognitive (e) Somatic (f) Cognitive-affective subscale (g) Somatic-performance subscale (h) Managing disease (i) Managing symptoms (j) Doing chores (k) Exercising (l) Participating in social activities (m) Physical health (n) Mental health (o) Total score (p) Self (q) Powerful others (r) Chance (s) Doctors (t) Total score
Mood
a b c
a
The BSI-18 was included in addition to the BAI and BDI-2 because it assesses patient's distress related to mental health symptoms, which may be distinct from the symptoms themselves. The Lorig scale was modified in our study from the standard 10-point scale to a shorter 5-point scale. QoL = quality of life.
M.L. Cohen et al. / Epilepsy & Behavior 34 (2014) 47–49
symptoms. However, the current results demonstrate that dissociative symptoms overlap strongly with mood symptoms and emotional distress, as well as certain beliefs about locus of control. Dissociation may be a unique entity, but our results indicate that more commonplace psychiatric features explain the majority of the variance of self-reported dissociative symptoms in patients with PNESs. The current results do not provide any guidance about how dissociative symptoms may resolve with treatment of mood symptoms or locus of control beliefs. The extant literature, however, suggests that they may not. One study found that after CBT, the average DES score among participants remained stable despite reduction in seizure frequency, fewer symptoms of depression and anxiety, fewer somatic complaints, improved quality of life, and improved psychosocial functioning [3]. This raises the question of whether dissociative symptoms are meaningful. Our data, as well as those of LaFrance et al. [3], suggest that dissociative symptoms are not independently related to quality of life. Together, these findings indicate that dissociative symptoms may not impact one's overall level of functioning independent of other factors. Similar to the perspective of Schmutz [25], our findings indicate that the reported dissociative experiences of PNESs are not necessarily mysterious but may overlap with the symptoms of other psychiatric conditions. Moreover, symptoms of PNESs may not be distinct from other functional neurological disorders [12]. Instead, PNESs, as well as other functional neurologic symptoms, may reflect a common underlying psychiatric morbidity. The present research supports this view, in part, by demonstrating that the majority of variance in dissociative experiences overlaps with more commonplace symptoms and beliefs that have been treated successfully with CBT. Future research is needed to determine if a similar pattern exists in other manifestations of functional neurologic symptoms. A potential limitation of this study is that we did not analyze subgroups of patients, for example, based on DES score or history of trauma, the latter of which is related both to PNESs and to symptoms of dissociation [26]. Patients with PNESs are certainly not a homogeneous group: perhaps, dissociation is not a core feature for all patients with PNESs, and dissociation may not be the only mechanism of altered consciousness in PNESs [27]. The present investigation suggests that for the average patient with PNESs who is a good candidate for CBT, dissociative symptoms do not necessarily contraindicate traditional CBT, as these symptoms strongly overlap with mood symptoms, mood distress, and beliefs about locus of control. Conflicts of interest The authors declare that there are no conflicts of interest. References [1] Goldstein LH, Drew C, Mellers J, Mitchell-O'Malley S, Oakley DA. Dissociation, hypnotizability, coping styles and health locus of control: characteristics of pseudoseizure patients. Seizure 2000;9:314–22.
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