Epilepsy Research (2009) 84, 91—96
journal homepage: www.elsevier.com/locate/epilepsyres
Non-Epileptic Seizures (NES) are predicted by
depressive and dissociative symptoms
Marianna Mazzaa,∗, Giacomo Della Marcab, Annalisa Martinia,
Marta Scoppettaa, Catello Vollonob,c, Maria Azzurra Valentib,
Maria Luigia Vaccariob, Pietro Briaa, Salvatore Mazzab
aInstitute of Psychiatry and Psychology, Catholic University of Sacred Heart, Via Ugo De Carolis, 48 00136 Roma, Italy
bDepartment of Neurosciences, Catholic University of Sacred Heart, Rome, Italy
cFondazione Pro Juventute Don Carlo Gnocchi, Rome, Italy
Received 4 September 2008; received in revised form 16 December 2008; accepted 27 December 2008
Available online 6 February 2009
Non-Epileptic Seizures (NES, or pseudo-seizures); (2) To compare NES with Epileptic subjects and
Normal controls; (3) To try to define a personality profile specific, or typical, of NES patients.
Methods: Patients: 30 consecutive patients (21 females and 9 males, mean age 32.9±11.7
years) with NES diagnosed on clinical basis and confirmed by video—EEG recording; 30 patients
with epilepsy matched for age and sex who had presented at least two seizures in the 12 months
prior to the study despite pharmacological treatment; 30 Control subjects, healthy volunteers,
matched for age and sex.
Psychometric evaluation: Hamilton Rating Scale for Depression (HDRS), Dissociative Experi-
ence Scale (DES), Minnesota Multiphasic Personality Inventory-2 (MMPI-2).
Groups were compared by means of one-way Analysis of Variance (ANOVA) for indepen-
dent samples, followed by posthoc Tukey HSD Test, with Bonferroni correction for multiple
Results: Depressive and dissociative symptoms showed a significantly higher prevalence in the
NES group as compared to Epileptics (p<0.001) and Controls (p<0.001), whereas patients with
epilepsy did not differ from Controls. The analysis of the MMPI-2 in NES group showed a general
increase in most MMPI-2 T-scores as compared to Epileptics and Controls, rather than a constant
elevation (T-score>70) of one or more scales. No specific personality profile could be identified
for the NES group.
Conclusions: Our results are consistent with the hypothesis that depression and dissociative
mechanisms are important precursors to the development and expression of NES.
© 2009 Elsevier B.V. All rights reserved.
∗Corresponding author. Tel.: +39 06 35348285; fax: +39 06 35501909.
E-mailaddresses:firstname.lastname@example.org, email@example.com (M. Mazza).
0920-1211/$ — see front matter © 2009 Elsevier B.V. All rights reserved.
92M. Mazza et al.
‘Pseudo-seizures’ are paroxysmal alterations in behaviour
that resemble seizures but are without any organic
cause (Bhatia, 2004). Several terms have been used
for pseudo-seizures, including: non-epileptic psychogenic
seizures, psychogenic seizures, hysterical seizures, and
hysteroepilepsy. Among them, the term ‘‘Non-Epileptic
Seizures’’ (NES) is preferred because it is non-judgmental,
often used, acceptable to patients and describes the clinical
phenomenon without suggesting causation (Bhatia, 2004).
No standardized, generally accepted diagnostic criterion
is available for NES, and therefore the definition of NES par-
tially varies in the series reported in literature. In routine
taneous video- and EEG-recording: a NES is an episode with
behavioural features similar to those usually reported by the
patient, mimicking an epileptic seizure, not associated with
EEG abnormalities (Reuber et al., 2005). Some movements
and behaviours are relatively specific to NES: side-to-side
head shaking, pelvic thrusting, opisthotonic posturing, bilat-
eral movements with preserved awareness, stuttering, and
weeping (Benbadis, 2005; Groppel et al., 2000).
Although video—EEG monitoring and telemetry have
improved the ability to distinguish NES from epileptic
seizures, access to correct diagnosis and treatment remains
limited. Besides, NES and ‘true’ epileptic seizures often
coexist in the same patient. It is estimated that 10—50% of
patients with ‘‘intractable epilepsy’’ have either NES alone
or a combination of epileptic and non-epileptic seizures (La
France et al., 2006). The mean latency between manifesta-
tion and diagnosis remains unacceptably long, since 75% of
NES patients, without epilepsy, are still treated with anti-
convulsants 7.2 years after the diagnosis (Reuber et al.,
2002, 2003). The management of NES as epileptic seizures
can lead to significant iatrogenic harm. Moreover, the fail-
ure to recognize the psychological causes of the disorders
detracts from addressing associated psychopathology and
enhances secondary somatization processes (Reuber and
Elger, 2003; Swinkels et al., 2005; Krumholz, 1999). Psy-
chogenic NES are usually classified as conversion seizures,
but NES can also represent misdiagnosed symptoms of
panic, dissociation, or traumatic flashbacks in the context
of posttraumatic stress disorder (PTSD) (Bowman, 1999).
NES patients have more dissociative pathology than gen-
eral psychiatric outpatients (Bowman and Markand, 1996).
A recent study by Fleisher et al. (2002) outlined that sub-
jects with pseudo-seizures seem to exhibit trauma-related
profiles that differ significantly from those of patients with
epilepsy and closely resemble those of individuals with a his-
tory of traumatic experiences. Recently Duncan et al. (2006)
described a distinct subgroup of patients with late onset
psychogenic non-epileptic attacks, in whom psychological
trauma related to poor physical health plays a prominent
The aim of our observational study was to identify and
measure depressive and dissociative symptoms of patients
with NES, and to try to define a psychopathological profile.
For this reason, we analyzed and compared three sample
populations: patients with NES, patients with epilepsy
and healthy controls. Each subject underwent a battery
of psychometric tests, including a structured psychiatric
interview, a personality inventory, and scales for the
evaluation of mood disorders and dissociative behaviour.
Three groups of subjects were enrolled: patients with NES (n=30),
patients with epilepsy (n=30) and healthy controls (n=30). NES
patients were enrolled consecutively, among the patients referring
to the Epilepsy Centre at the Neurology Institute of Catholic Uni-
versity of Sacred Heart of Rome from June 2005 to June 2006. The
diagnosis of NES was made on the basis of clinical and video—EEG
assessment. Only patients with at least two documented NES were
enrolled in the study. NES group included 18 patients with ‘‘pure’’
NES and 12 patients with NES and epilepsy. This criterium was
adopted in order to explore the personality profile of the NES
population which is most frequently encountered in the practice
of clinical epileptology (Kuyk et al., 2003; Devinsky et al., 1996;
O’Sullivan et al., 2007).
A group of patients with epilepsy, matched for age and sex, was
randomly selected, the only inclusion criteria for epileptic patients
was the occurrence of at least two seizures in the 12 months prior
to the study, despite pharmacological treatment. A control group
of healthy volunteers, matched for age and sex, was enrolled.
Exclusion criteria, for both groups, were psychosis, alcohol or
drug addiction and organic psychiatric disorders. Patients younger
than 18 and older than 65 years were excluded. None of the NES
patients was receiving a drug therapy at the moment of the recruit-
ment, except for low doses of benzodiazepines in three cases.
Subjects who met the criteria for both pseudo-seizures and epilepsy
were included in the NES group.
The study design was approved by the local ethical committee,
and all patients and normal subjects who agreed to participate were
fully informed and gave their written consent.
The diagnosis of NES was made on the basis of the anamnesis and the
video—EEG finding. In particular, the events were classified as NES
if they met the following criteria: (1) absence of EEG changes in
association with the behavioural manifestation, and (2) the clin-
ical phenomenon corresponded to the patient’s typical event as
confirmed by a family member or a friend who had previously
witnessed the events (Farias et al., 2003). Video—EEG recording
was performed by means of 19 scalp leads, placed according to
the 10—20 system, with earlobe reference. Both longitudinal and
transversal bipolar derivations were employed. Video-recordings
were performed by means of two digital cameras, synchronized
with the EEG traces; the images of the two cameras (one display-
ing the whole patient, another focusing on details of the face, or
the limbs involved by the seizure) were merged by a video mixer.
When a seizure occurred, a trained EEG technician performed a
brief clinical exam, repeated both during and immediately after
the seizure, including evaluation of: motility and muscle tone in
the limbs, description of automatic motor activities (i.e. chewing),
response to verbal and tactile stimulation, memory of the event
(‘‘do you remember what happened?’’), presence of blink response
to threat, speech impairment (denomination of common objects).
The absence of any EEG modification (even including the disappear-
ance of background alpha rhythm), together with the lack of any
clinical modification during and after the seizure, suggested the
classification of the event among the pseudo-seizures. Recordings
in which the EEG was technically unsatisfactory or equivocal were
excluded from the study. The frequency of attacks in the previous
6 months, obtained from patients’ diaries, was compared among
Non-Epileptic Seizures (NES) are predicted by depressive and dissociative symptoms93
Demographic variables in the three groups. NES, Non-Epileptic Seizures; SD, Standard Deviation.
VariablesNES Epilepsy Controls
Number of subjects
Age (years, mean±SD)
Education (years, mean±SD)
Duration of disease (years, mean±SD)
Age at onset (years, mean±SD)
Time to diagnosis (years, mean±SD)
Number of attacks (past 6 months)
the 2 groups (NES vs Epilepsy), and no significant difference was
observed (Table 1).
Each patient (NES and Epilepsy groups) underwent a full medical
and neurological evaluation, including EEG, video—EEG and neu-
roimaging (MRI). All subjects enrolled in the NES and Epilepsy groups
underwent a Structured Clinical Interview for DSM-IV Axis I Disorders
(SCID-I), and were studied relatively to the personality through the
Structured Clinical Interview for DSM-IV Axis II Disorders (SCID-II).
All the subjects in the 3 groups underwent a battery of psycho-
metric tests, administered by a trained clinical psychologist. The
battery included: (1) 21-items Hamilton Rating Scale for Depres-
sion (HDRS); (2) Dissociative Experience Scale (DES); (3) Minnesota
Multiphasic Personality Inventory-2 (MMPI-2).
Individual MMPI profiles were classified according to the methods
proposed by Graham (1987) and also according to the method sug-
gested by Friedman et al. (1989) modified by Kalogjera-Sackellares
and Sackellares (1997).
each profile on the basis of its two highest scales. The two-point
code method of classification does not depend on the absolute ele-
vations of individual scales. Nevertheless, the descriptors presented
for a particular code-type are more likely to fit a subject if the
two scales are both elevated above T=70 and if the two scores
are significantly higher (>5) (Kalogjera-Sackellares and Sackellares,
1997) than other clinical scales in the profile. In order to take into
account the absolute scale elevations (which is important, because
it is thought to reflect the extent of disturbance) we also anal-
ysed the profiles by a more focused application of Graham’s method
(Graham, 1987). We assigned the two-point codes only to those
MMPI profiles in which the two highest scales were both elevated
We further analysed the MMPI profiles using the method
described by Friedman et al. (1989) (Friedman method). It entails
the following code-types: spike code, two-points code, three-points
code and codes with four elevations. In accordance with the mod-
ification proposed by Kalogjera-Sackellares and Sackellares (1997),
we defined ‘normal’ profiles those in which all the scales showed a
T-score<70 and we classified the records with four or more eleva-
tions into a single category named ‘multiple elevations’.
Finally, three distinct sets of MMPI-2 criteria for hysteria or con-
version were applied: those proposed by Marks and Seeman (1963),
Wilkus et al. (1984) and Duckworth and Anderson (1995).
The scores of the HDRS, DES and MMPI-2 were compared among the
three groups (NES, patients with epilepsy and Controls) by means
of one-way Analysis of Variance (ANOVA) for independent samples,
followed by posthoc Tukey HSD Test, with Bonferroni correction for
multiple comparisons, with an adjusted significance level of 0.0015
Demographic characteristics of the samples are presented
in Table 1. The mean age of patients was 32.9±11.6 (mean
age±standard deviation) for NES group, 29.7±9.4 for the
Epilepsy group, 34.6±10.9 for the Control group (ANOVA:
not significant, F=1.6; p=0.2). Sex composition was the
same in the 3 groups: NES: 9 males, 21 females; patients
with epilepsy: 10 males and 20 females; Controls: 10 males
and 20 females. No significant difference was observed in
the number of attacks in the previous 6 months between
the 2 groups (NES vs Epilepsy).
Both the HDRS and the DES scores were significantly
higher in the NES group as compared to the Epilepsy and
Control groups (Table 2). The highest DES scores of the NES
patients concerned the items 14 (mean score: 53.0%), 17
(mean score: 30.3%), 12 (mean score: 28.9%) and 15 (mean
score: 28.3%); the lowest scores were those in response
to the items 27 (mean score: 0.04%) and 11 (mean score:
The analysis of the MMPI-2 performed according to the
Graham method showed a variety of two-point code types,
and no single two-point code was dominant. The number
of cases in which a given clinical scale was the highest in
the profile (regardless of absolute elevation) was computed;
the scale with most frequent prevalent T-score was ‘Ma’
(8/30) followed by ‘Pd’ and ‘Hs’ (6/30) and ‘Pa’ and ‘D’
(4/30). Also the number of cases in which a given clinical
scale was one of the two highest in the profile (regardless of
absolute elevation) was computed; the scale with most fre-
quent prevalent T-score were ‘Pa’ and ‘Hs’ (10/30) followed
by ‘Ma’ and ‘Pd’ (9/30) and ‘D’ (8/30). The application of
the ‘focused’ variant of Graham’s method (Graham, 1987)
allowed to classify 8 out of 30 profiles characterized by 2
scales with T-scores≥70, but no predominant profile could
be pointed out.
94 M. Mazza et al.
Dissociative Experience Scale; NES, Non-Epileptic Seizures; E, Epilepsy; C, Controls. Scores are expressed as mean±standard
deviations. n.s., not significant.
HDRS and DES average scores and comparisons among the three groups. HDRS, Hamilton Depression Rating Scale; DES,
NES vs ENES vs C E vs C
14.4 ± 4.6
17.6 ± 8.9
6.0 ± 5.2
6.4 ± 5.8
6.0 ± 3.0
4.5 ± 2.9
the three groups. Dot lines indicates cut-off values for normal
score (T=70). NES, Non-Epileptic Seizures; n.s., not significant.
Hs, Hypochondriasis; D, Depression; Hy, Conversion Hysteria;
noia; Pt, Psychasthenia; Sc, Schizophrenia; Ma, Hypomania; Si,
Comparison of MMPI-2 basic scales T-scores among
The analysis of the MMPI-2 performed according to the
Friedman method showed normal profiles in 15/30 subjects,
spike profile in 8/30, a two-point code in 1/30, a three-
points code in 1/30 and a multiple elevation in 5/30.
The prevalence of conversion was: 0/30 using the crite-
ria of Marks and Seeman (1963), 7/30 using the criteria of
Wilkus et al. (1984), 5/30 using the criteria of Duckworth
and Anderson (1995) (coincidence occurred in 3 subjects).
As concerns the comparison of the MMPI-2 scores among
the groups, the NES group presented significantly higher T-
scores in all the basic scales, with the exception of the
scales, ‘Hy’ (Hysteria), ‘Mf’ (Masculinity—Femininity), ‘Pt’
(Psychasthenia) and ‘Si’ (Social introversion). MMPI basic
scales result and comparisons among groups are shown in
The SCID- I and II allowed a definite psychiatric diagnosis
in 16/30 patients in the NES group, and in 9/30 patients
of the patients with epilepsy; these diagnosis are listed in
The most relevant result of our observation is that the
patients with NES show higher scores in the scales for
depression and dissociation as compared with both normal
controls and patients with epilepsy. HDRS and DES aver-
age scores showed a more than two-fold increase in NES
as compared to patients with epilepsy and Controls. The
prevalence of depressive symptoms in NES has been widely
reported (Breier et al., 1998; Ettinger et al., 1999; Kanner
et al., 1999; Goldstein et al., 2000; Prueter et al., 2002).
Also dissociative symptoms have been frequently described
in association with NES (Kanner et al., 1999; Goldstein et
al., 2000; Prueter et al., 2002; Harden, 1997); in particular,
dissociation is likely to be one of the principal psychogenic
mechanism of pseudo-seizures. Iriarte et al. (2003) (Iriarte
et al., 2003) suggested that psychogenic pseudo-seizures are
conversive or dissociative disorders that can be considered
as the expression of unconscious psychological processes,
therefore not under patients’ voluntary control. In this
respect, our data substantially confirm the findings of pre-
vious literature (Breier et al., 1998; Ettinger et al., 1999;
Kanner et al., 1999; Goldstein et al., 2000; Prueter et al.,
2002; Harden, 1997).
to SCID I and II (DSM-IV), in the NES and in the Epilepsy groups.
Distribution of the psychiatric diagnosis, according
Non-Epileptic Seizures (NES) are predicted by depressive and dissociative symptoms95
On the contrary, we did not find significant differences in
the HDRS and DES scores of patients with epilepsy and Con-
trols. In this respect, previous literature reports discordant
data. Increased depression scores in patients with epilepsy
have been frequently observed (Baker, 2006). The occur-
rence of dissociative symptoms in patients with epilepsy is
controversial, since it has been described in some studies
(Alper et al., 1997) and not in others (Prueter et al., 2002;
Devinsky et al., 1989). The discordance between our data
and those previously reported could depend on the selection
criteria: our patient were selected from a general popu-
lation referring to an Epilepsy clinic, whereas most of the
results reported in literature come from patients evaluated
in pre-surgical settings. These latter patients have a higher
prevalence of psychiatric comorbidity, because they have
more severe epilepsies, drug-resistance, polytherapies, and
concomitant brain lesions, particularly in the frontal or tem-
In our sample, the coexistence of severe depressive
and dissociative symptoms seems to define a specific psy-
chopathological profile of NES with respect to epilepsy. It
must be considered, anyway, that we enrolled in the NES
group both patients with ‘‘pure’’ NES and patients with NES
and epilepsy, in order to reply, in our study design, the situ-
ation which is most frequently encountered in the practice
of clinical epileptology (Kuyk et al., 2003; Devinsky et al.,
1996; O’Sullivan et al., 2007).
The application of the MMPI was aimed at identifying
personality traits, or personality profiles, which could be
‘specific’, or frequently associated, with pseudo-seizures.
Neither the Graham’s method (Graham, 1987) (including
its ‘focused’ version Kalogjera-Sackellares and Sackellares,
1997) nor the Friedman’s methods (Friedman et al., 1989)
allowed to identify specific code-types or personality pro-
files which were predominant in the NES or the Epilepsy
group. As concerns the personality profiles, the NES groups
showed normal findings in most cases (15/30 according to
Friedman’s criteria). Consequently, average T-score in basic
scales of MMPI-2 the NES population were all below the
cut-off value of 70. Among the NES patients with abnormal
T-scores (≥70), the most frequently elevated scales were
Hs and PA, followed by Ma and Pd; also D scale showed fre-
quently elevated T scores. This is in agreement with the
increased HDRS found in the NES groups. In all the basic
scales, the NES group as a whole showed significantly higher
scores as compared to the Epilepsy and the Control Groups.
These two latter groups were not significantly different.
In the clinical study of pseudo-seizures it is mandatory
to investigate for hysteric or conversion personality traits
(Prueter et al., 2002; Drake et al., 1992; Andriola and
Ettinger, 1999). The MMPI-2 provides some indexes of con-
version or hysteria. In particular, the T-score for the ‘Hy’
scale was normal in all the NES, moreover, this was one of
the T-scores which did not show significant differences in
the 3 groups (Fig. 1). The other item referring to conver-
sion disorders, ‘Hs’, was elevated in 8 NES subjects; this
allowed to assess the presence of ‘conversion’ symptoms in
a subset of patients, whose number varied, according to the
criteria applied, from 0/30 to 7/30. This variability confirms
that the more widely accepted and standardized criteria are
necessary to assess and measure the role of conversion and
hysteria in the pathogenesis of pseudo-seizures.
Dissociation is a relevant issue in the pathogenesis of
pseudo-seizures. Despite the recognized clinical significance
of dissociation, there is an ongoing controversy about its
conceptualization (Spitzer et al., 2006), that is reflected
by differences in the definition and classification of disso-
ciative disorders in the ICD-10 (WHO, 1991) and the DSM-IV
(APA, 1994). In fact, conversion disorders are a group among
the somatoform disorders in the DSM-IV, while the ICD-10
claims that dissociative and conversion disorders represent
one category that is independent from the somatoform dis-
orders. As Bowman (2006) recently wrote, it is a scientific
embarrassment to continue to deny the dissociative nature
of pseudo-seizures. Our study confirms that patients who
have pseudo-seizures show substantial rates of dissociative
symptoms. The success of these patients’ treatment may
be affected adversely by their dissociative disorders. In
contrast with prior research, increased dissociation (DES)
scores were not associated with high elevations on MMPI-2
scales typically associated with psychotic symptoms (Allen
and Coyne, 1995). In our NES group, the finding of elevated
DES scores is not reflected by the predominant elevation of
a single, specific T-score, but it was associated with a gen-
eral increase in most MMPI-2 T-scores; this is partially in
agreement with the results of Leavitt (2001).
In conclusion, our study failed, as well as most of previ-
ous investigations, in defining a specific personality pattern
of pseudo-seizures. Nevertheless, our results suggest that a
peculiar combination of depressive and dissociative symp-
toms, in a population of patients with paroxysmal disorders,
increased likelihood of at least some events being NES.
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