Seizure (2008) 17, 247—253

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Psychiatric diagnoses of patients withpsychogenic non-epileptic seizures

Renato Luiz Marchetti a,*, Daniela Kurcgant a, Jose Gallucci Neto a,Mary Ann von Bismark a, Liliana Beccaro Marchetti a, Lia Arno Fiore b

a Projeto de Epilepsia e Psiquiatria (PROJEPSI), Instituto e Departamento de Psiquiatria doHospital das Clınicas da Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, SP, Brazilb Laboratorio de Neurofisiologia, Instituto e Departamento de Psiquiatria do Hospital dasClınicas da Faculdade de Medicina da Universidade de Sao Paulo, SP, Brazil

Received 20 April 2007; received in revised form 19 June 2007; accepted 10 July 2007

KEYWORDSPNES;Psychogenic non-epileptic seizures;Pseudoseizures;Epilepsy;Differential diagnosis;Psychiatric diagnosis;Mental disorders

Summary

Objective: Our purpose was to present and discuss the psychiatric diagnoses ofpatients who presented psychogenic non-epileptic seizures (PNES) during video-electroencephalographic monitoring (VEEG).Methods: Out of 98 patients, a total of 28 patients presented PNES during thediagnostic procedure. In those cases in which the PNES that occurred during VEEGwere validated by clinical history (clinical validation), and by showing the recordedevent on video to an observer close to the patient (observer validation), was definedpsychogenic non-epileptic seizure disorder (PNESD). Psychiatric diagnoses were madeaccording to DSM-IV.Results: In 27, psychogenic non-epileptic seizures disorder was diagnosed. Fourteenpatients presented only with psychogenic non-epileptic seizure disorder, 13 with bothpsychogenic non-epileptic seizures disorder and epilepsy, and one patient withepilepsy only. Psychiatric diagnoses were: 17 (63%) patients with conversion disorder,five (19%) with somatization disorder, two (7%) with dissociative disorder NOS, two(7%) with post-traumatic stress disorder and one (4%) with undifferentiated somato-form disorder.Conclusions: Dissociative-conversion non-epileptic seizures are the most frequentfinding, representing the pseudoneurological manifestation of mental disorders thathave these symptoms as a common feature. Provisionally, they may be defined asdissociative-conversion non-epileptic seizure disorders.# 2007 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

* Corresponding author at: Rua Cayowaa 1236 ap61, Sao Paulo CEP: 05018-001, SP, Brazil. Tel.: +55 11 3672 2426; fax: +55 11 3672 2426.E-mail address: rlmarche@dialdata.com.br (R.L. Marchetti).

1059-1311/$ — see front matter # 2007 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.doi:10.1016/j.seizure.2007.07.006

248 R.L. Marchetti et al.

Introduction

Non-epileptic seizures (NES) are characterized byrecurrent seizures, attacks or fits that may be mis-taken for epileptic seizures (ES) because of theirsemiological similarities, but that, nevertheless,are not caused by abnormal cortical discharges.They may be of physiologic or psychogenic (PNES)origin and the former are clearly more frequent.Studies on the prevalence of PNES show variable,but clinically significant results: from 5 to 33% ofoutpatients receiving treatment for epilepsy1,2 andfrom 10 to 58% of inpatients treated for refractoryepilepsy present PNES.3—5 Prevalence in the generalpopulation is estimated from 2 to 33/100,000.5 Theonly epidemiological studies in this field showed ayearly incidence of 1.4—3.0\100,000 of PNES in thegeneral population.6,7 According to Gates8 such asignificant difference in results may be explained bydifferences in diagnostic criteria for PNES.

For several centuries PNES and their manifoldpresentations have challenged and puzzled bothpsychiatrists and neurologists. From the 1980sonwards knowledge on PNES has grown significantlydue to the widespread use of intensive video-elec-troencephalographic (VEEG) monitoring. Currently,VEEG is considered the ‘‘gold standard’’ for properdiagnosis of PNES. Strangely enough, the diagnosisof PNES does not have a nosological status, becauseit is considered as a mere provisional diagnosticstage, before the medical condition manifested asPNES is finally determined. A long list of mentaldisorders may present as PNES.8 The purpose of thisstudy is to present and discuss the psychiatric diag-noses of a group of patients that presented PNESduring intensive VEEG monitoring.

Methods

From 2002 to 2006, 98 patients underwent pro-longed intensive VEEG monitoring at the Laboratoryof Clinical Neurophisiology of the Institute of Psy-chiatry of the Hospital das Clınicas of the Universityof Sao Paulo, Brazil. Out of these, a total of 28patients presented PNES during the diagnostic pro-cedure. Patients were submitted to VEEG for one ofthe following reasons: pre-surgical evaluation aspart of an epilepsy surgery program, diagnosticelucidation of clinically refractory seizures and sus-pected PNES. Patients remained at the VEEG unit forvariable periods, during which behavior and EEGactivity were simultaneously registered for identi-fication, characterization and quantification ofevents. Equipment utilized was digital BiologicSystems Corp., with Ceegraph PTI Version 6.72.06

software. We used the International Electrode Sys-tem Placement with additional zygomatic and EKGelectrodes. At first, basal records (sleep and wake-fulness) with the usual activation procedures(hyperventilation and photostimulation) wereobtained, while maintaining habitual anti-epilepticdrug (AED) dosages.

In all patients in whom VEEG was carried outbecause of suspected PNES, and in all patientsinvestigated for other reasons who presented spon-taneous PNES, the following sequential steps werecarried out as a research ‘‘suggestion’’ protocol forseizure induction: simple suggestion, suggestioninterview, hypnotic induction with either intra orpost-hypnotic suggestion, and intravenous placeboinfusion (saline solution). As soon as a PNES wasobtained the sequence was interrupted.

After this sequential procedure, AEDs were gra-dually discontinued and records were obtained forobservation of events and EEG tracing changes,during periods considered long enough for diagnosis.In all patients in which PNES had been previouslysuspected or in which either spontaneous or pro-voked PNES were obtained, typical hospital stay inthe VEEG unit was of 3 weeks (range from 1 to 6weeks). Longer than usual monitoring periods werecarried out to verify possible occurrence of epilepti-form discharges in EEG tracings or of late ES follow-ing complete AED discontinuation.

An event occurring at anymoment was defined asan ES when accompanied by unequivocal dischargesor ictal EEG patterns before, during or soon after itsoccurrence otherwise it was defined as PNES. Allrecorded events were analyzed and shown to familymembers, so that they could confirmwhether theseevents were or not present in the patient’s dailylife.

Some patients may, in extreme conditions, suchas those in prolonged intensive monitoring by VEEG,present isolated PNES, without however constitut-ing a clinical problem.9 Only in those cases, config-uring a de facto clinical problem, in which the PNESthat occurred during VEEGwere validated by clinicalhistory (clinical validation), and by showing therecorded event on video to an observer close tothe patient (observer validation), was considered asa present diagnosis, defined as psychogenic non-epileptic seizure disorder (PNESD). On the otherhand, some patients with epilepsy may occasionallynot present ES during prolonged intensive VEEGmonitoring. In those patients from our sample inwhich ES did not occur, epilepsy was defined aspresent if and when unequivocal interictal epilepti-form discharges (sharp waves, spikes or spike—wavecomplexes) were found, and when the occurrence ofES was confirmed by clinical and observer valida-

Psychiatric diagnoses of patients with psychogenic non-epileptic seizures 249

tion. Benign variants were not considered as epi-leptiform.

For each patient the following diagnostic possi-bilities were considered:

(1) E

pilepsy: Current diagnosis of epilepsy absent,in remission, in remission under treatment,mildly active, moderately active, or severelyactive. Diagnoses of ES and epileptic syndromeswere defined.

(2) P

NESD: Current diagnosis of PNESD absent, inremission, in remission under treatment, mildlyactive, moderately active or severely active.Diagnoses of mental disorders presenting asPNESD were defined.

(3) E

pilepsy and PNESD: The following levels ofconviction obtained by diagnostic investigationwere attributed: presumed, probable and defi-nitive.

Psychiatric comorbidities eventually associatedto epilepsy, PNESD or both were defined.

Neurological, psychiatric, imaging studies (MRI,interictal SPECT and eventually ictal SPECT) andneuropsychological evaluations were carried outon all patients.

Once diagnoses were established they were com-municated to patients and family members, andtreatment referrals done.

Diagnoses of ES were defined according to theCommission on Classification and Terminology of theInternational League Against Epilepsy.10 Diagnosesof epileptic syndromes were defined according tothe Commission on Classification and Terminology ofthe International League Against Epilepsy.11 Diag-noses of mental disorders were defined according toDSM-IV.12

Psychiatric evaluations were alternatively car-ried out by one of three professionals (JGN, MAVBand RLM), with both training and experience inneuropsychiatric issues in epilepsy, by open clinicalinterviews during the period in which the patientunderwent VEEG monitoring. Every evaluated casewas submitted to a team revision by the threepsychiatrists until a diagnostic consensus wasreached. Neurological evaluations were carriedout by a team of epileptologists and clinical neuro-physiologists with experience in VEEG monitoring(LAF).

An information statement, in which all the pro-cedures of VEEG monitoring were explained, wasgiven and discussed with the patients and theirrelatives before the beginning of each investigation.All patients provided written informed consent andthe protocol was in agreement with the institutionalresearch ethics board.

Results

Out of 28 patients, 22 (78.6%) were referred tointensive monitoring by VEEG for suspected PNES.Six patients (21.4%) were referred for other reasons,and therefore did not have an initial diagnostichypothesis of PNES. Two of these (7.1%) werereferred for pre-surgical evaluation and four(14.3%) for diagnosis of clinically refractory epilep-tic syndromes.

Results are presented on Table 1. Out of 28patients 26 (93%) were female. Mean age was of37 years (range from 19 to 62, median = 38 andS.D. = 10).

No patients presented physiologic non-epilepticseizures during intensive monitoring by VEEG, nordid they present suggestive data for its occurrencein everyday life (only PNES occurred either duringmonitoring or as a clinical problem).

Patients were divided into three groups: PNESDgroup, made up by 14 patients who presented PNESduring monitoring, evidence of PNESD (PNES con-firmed by clinical or observer validation) andabsence of epilepsy; PNESD/E group, made up by13 patients who presented PNES during monitoring,evidence of PNESD and epilepsy; E group–—made upby only one patient (case 28) who presented PNESduring monitoring, but not evidence of PNESD (PNESnon confirmed by either clinical or observer valida-tion), and nevertheless presented epilepsy. There-fore, out of 28 patients, 27 presented a provisionaloperational diagnosis of PNESD. In these patients,psychiatric diagnoses were divided as: 17 (63%) withconversion disorder, five (19%) with somatizationdisorder, two (7%) with dissociative disorder NOS,two (7%) with post-traumatic stress disorder, andone (4%) with undifferentiated somatoform disor-der. Out of 28 patients, 19 (68%) presented psychia-tric comorbidities. Diagnoses were divided into, 10(36%) patients with major depressive disorder (sixwith recurrent episodes and four with single epi-sodes), one (4%) with dissociative disorder NOS, two(7.1%) with histrionic personality disorder, one (4%)with borderline personality disorder and one (4%)with anti-social personality disorder.

Discussion

PNES may lead to severe social and psychologicalimpairments. Patients and their family members aresubject to the same problems as people with epi-lepsy: stigmatization, poor schooling, unemploy-ment, difficult interpersonal relationships, andsocial maladaptation.13 In addition, from the med-ical point of view, patients are exposed to iatrogenic

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Table 1

Patient Reason for VEEG Age Sex ES inVEEG

Epilepsydiagnosis

Epilepsy diagnosislevel of conviction

ES diagnosis Epileptic syndromediagnosis

PNESD diagnosis PNESD diagnosislevel ofconviction

PsychiatricPNESD diagnosis

Psychiatric comorbidity

PNESD group01 Suspected PNES 39 F No Absent Definitive — — Moderately active Definitive Conversive dis Borderline personality dis02 Suspected PNES 29 F No Absent Definitive — — Severely active Definitive Conversive dis Absent03 Suspected PNES 19 F No Absent Definitive — — Severely active Definitive Conversive dis Absent04 Suspected PNES 58 F No Absent Definitive — — Moderately active Definitive Somatization dis Major depressive dis–—recurrent05 Suspected PNES 29 M No Absent Definitive — — Severely active Definitive Conversive dis Generalized anxiety dis06 Diag refractory epi 37 M No Absent Definitive — — Severely active Definitive Conversive dis Major depressive dis–—single07 Suspected PNES 33 F No Absent Definitive — — Severely active Definitive Somatization dis Absent08 Suspected PNES 44 F No Absent Definitive — — Moderately active Definitive Conversive dis Absent09 Suspected PNES 41 F No Absent Definitive — — Mildly active Definitive Somatization dis Major depressive dis–—recurrent10 Suspected PNES 26 F No Absent Definitive — — Severely active Definitive Conversive dis Major depressive dis–—single11 Suspected PNES 39 F No Absent Definitive — — Severely active Definitive Conversive dis Dissociative dis NOS12 Suspected PNES 45 F No Absent Definitive — — Moderately active Definitive Conversive dis Absent13 Suspected PNES 24 F No Absent Definitive — — Severely active Definitive Conversive dis Absent14 Suspected PNES 40 F No Absent Definitive — — Severely active Definitive Somatization dis Histrionic personality dis

PNES/E group15 Suspected PNES 38 F No Remission Definitive SGS TLE/Sympto/

NeurocisticercosisSeverely active Definitive Undifferentiated

somatoform disAbsent

16 Diag refractory epi 32 F No Remissionunder treat

Definitive SGS FLE/Sympto/Schizencephalyand nodularheterotopies

Severely active Definitive Somatization dis Anti-social personality dis

17 Pre-surgicalevaluation

31 F Yes Severelyactive

Definitive CPS TLE/Sympto/TMS Mildly active Definitive Dissociativedis NOS

Major depressive dis–—recurrent

18 Suspected PNES 39 F No Remission Definitive Unclassified Undeterminedepilepsy/Crypto

Severely active Definitive Conversive dis Major depressive dis–—recurrent

19 Suspected PNES 19 F No Remission Definitive Unclassified Undeterminedepilepsy/Crypto

Severely active Definitive Conversive dis Dissociative dis NOS

20 Pre-surgicalevaluation

62 F Yes Moderatelyactive

Definitive CPS TLE/Sympto/TMS Moderately active Definitive Conversive dis Major depressive dis–—single

21 Suspected PNES 35 F No Remissionunder treat

Definitive Myoclonic Juvenile myoclonicepilepsy

Severely active Definitive Conversive dis Major depressive dis–—recurrent

22 Suspected PNES 51 F Yes Severelyactive

Definitive CPS TLE/Crypto Mildly active Definitive Post-traumaticstress dis

Mood dis due to topiramate-depressive features

23 Suspected PNES 41 F No Moderatelyactive

Probable CPS TLE/Sympto/TMS Moderately active Presumed Post-traumaticstress dis

Major depressive dis–—single

24 Suspected PNES 44 F No Severelyactive

Probable SGS FLE/Crypto Severely active Presumed Dissociativedis NOS

Major depressive dis–—recurrent +histrionic personality dis

25 Diag refractory epi 37 F No Remissionunder treat

Definitive Absences/TCGS Childhoodabsence epilepsy

Severely active Definitive Conversive dis Psychotic dis due to epilepsy

26 Suspected PNES 27 F No Remissionunder treat

Probable Unclassified Undeterminedepilepsy/Crypto

Severely active Definitive Conversive dis Anorexia nervosa

27 Suspected PNES 44 F Yes Remissionunder treat

Probable Absences Juvenile absenceepilepsy

Severely active Definitive Conversive dis Absent

E group28 Diag refractory epi 33 M Yes Severely

activeDefinitive CPS FLE/Crypto Absent Definitive — Absent

Psychiatric diagnoses of patients with psychogenic non-epileptic seizures 251

procedures such as, unnecessary use of high doses ofAEDs,14 venous punctures, intravenous AED use, andorotracheal intubation.15 Moreover, comorbiditywith depressive and anxiety disorders is high,16,17

and quality of life (QOL) of these patients is belowthat of patients with refractory epilepsy.18

Martin et al.19 estimated that, during the lifetimeof an individual with PNES, around US$ 100,000 willbe spent on diagnostic and therapeutic proceduresas well as AEDs. They also calculated that from US$100 to 900 million are spent yearly in the USA onpatients presenting PNES. Several studies show thatearly and correct diagnosis of PNES, followed byadequate treatment, could lead either to remissionin 19—25%, or to improvement in 75—95%. There-fore, correct diagnosis and treatment might resultin a significant reduction of utilization and cost ofhealth programs.16,19—21

The strategy to reach diagnosis is based ondetailed clinical history and characterization ofseizure semiology, aiming to circumscribe the dif-ferential diagnostic field to a few limited diag-nostic hypotheses such as epilepsy andalternatively physiologic or psychogenic non-epi-leptic events. Naturally, detailed knowledge ofthese alternatives is necessary to reach a properfinal diagnosis.

The possibility of PNES is usually considered whenthe patient presents a complete absence of ther-apeutic response to AED, loss of response (thera-peutic failure), or paradoxical responses (worseningor spontaneous and unexpected remissions). Like-wise, PNES may be considered because of atypical,multiple, inconsistent or changing seizure patterns,or when the seizures are provoked by evident andspecific emotional stress, with a narrow temporalrelation to seizure occurrence.22 These previouselements are considered particularly when thepatient presents normal ancillary exams (interictalroutine EEGs, imaging studies such as CT, MRI andSPECT).23,24 These situations guide the attentiveclinician towards a referral to centers specializedin differential diagnoses and intensive VEEG mon-itoring. However, a significant minority (21.4%) inour sample presented PNES as an unexpected phe-nomenon during an investigative process directedotherwise, such as pre-surgical evaluations or diag-nostic investigations of clinically refractory epilep-tic syndromes. In most cases there was aconcomitant diagnosis of epilepsy. This fact accent-uates the importance of PNES as a complicatingelement in the diagnosis and treatment of patientswith epilepsy. Estimated prevalence of PNES isalways higher when studies are carried out in cen-ters specialized in the clinical or surgical treatmentof epilepsy.3,8,25,26

A female preponderance, of up to 80%, has beenobserved in some studies of patients with PNES.27,28

In our sample, an even higher female proportion wasobserved (93%).

The absence of physiologic non-epileptic seizuresin our group is in agreement with other recentstudies.17,29 Syncope is the most common cause ofphysiologic non-epileptic seizures. Acute intoxica-tions by cocaine, metabolic disorders, movementdisorders, transitory ischemic attacks, and migraineare other less frequent diagnostic possibilities.30

The most common causes of physiologic non-epilep-tic seizures are regularly searched and rejected byeven the simpler investigative protocols applied inmost neurological centers, and therefore do notpose a significant referral shift to differential diag-nosis by VEEG monitoring.

Surely, one of the clinical situations that generatediscussion, is the association of epilepsy and PNESD.It is estimated that from 10 to 73% of patients withPNESD also present epilepsy.3,17,26 In an epidemio-logical study carried out in Iceland6 this associationwas found to be of 50%. In our study, associationoccurred in 14 (50%), a high rate, in accordance withseveral authors. The etiology of this phenomenon isas yet unknown. In one of our cases (case 28), thepatient presented spontaneous as well as provokedPNES during intensive VEEG monitoring, but theevents were not clinically validated neither con-firmed by observer validation. In this case, complexpartial ES with frontal origin were also observed andwere validated by both clinical history and observa-tion of the video recording by his mother. This caseemphasizes the importance of distinguishing theconcepts of PNES and PNESD. Analogously to theassertion that a single ES is insufficient for thediagnosis of epilepsy, occasionally, suggestible indi-viduals may present isolated PNES, particularlywhen exposed to a favorable situation such as inten-sive VEEG monitoring.9 Such occurrences, althoughuncommon, point out the importance of PNES vali-dation, whether spontaneous or provoked, bydetailed clinical history (clinical validation) andobservation of video recording of the event by anexternal observer close to the patient (observervalidation).

Although the differential diagnosis of PNESembraces an ample series of psychopathologicaldisorders, from a practical point of view, patientswho typically present episodes characterized bydisrupted consciousness or motor/sensory manifes-tations, presenting as pseudoneurological symp-toms, are those who have the highest chance ofbeing misinterpreted as suffering from epilepsy andreferred to specialized differential diagnosis.Although such manifestations may be intentionally

252 R.L. Marchetti et al.

Figure 1 Schematic representation of the nosologicalstatus of DCPNESD in relation with other mental disordersin DSM-IV.

produced, as in factitious disorders andmalingering,they may be involuntary (unconsciously produced),as observed in mental disorders coursing withdissociative or conversion symptoms. From the psy-chopathological point of view, in all patients of ourseries, PNES was the pseudoneurological presenta-tion of dissociative or conversion symptoms. In noneof our patients any other psychiatric symptom wasmanifested as PNES, suggesting that PNES provokedby dissociative or conversion symptoms are the onesthat in fact represent a significant clinical issue. Asoccurs with physiologic non-epileptic seizures,other common symptoms that may easily be mis-taken as ES, such as panic attacks, aggressive beha-viors and psychotic symptoms, are regularlyidentified and excluded by less comprehensive pro-tocols. For such reasons we suggest dissociative-conversion PNES (DCPNES) as a specific diagnosticterm. Likewise, for patients in which DCPNES arerecurrent and pose a significant clinical problem wesuggest the term DCPNES disorder (DCPNESD). Asobserved in our series, patients with DCPNESD maypresent the following mental disorders: conversiondisorder, somatization disorder or undifferentiatedsomatoform disorder, dissociative disorder NOS andpost-traumatic stress disorder. As previouslypointed out, the strategy for reaching the diagnosisof PNES is based on detailed clinical history andseizure characterization, thus circumscribing thedifferential diagnostic field to some limited diag-nostic hypotheses for epilepsy and otherwise forphysiologic non-epileptic seizures and PNES.Detailed knowledge of these alternatives is ofutmost importance in reaching the final diagnosis.Therefore, a particular clinical presentation will notsuggest only a general diagnosis of epilepsy, butrather some possibilities of specific epileptic syn-dromes, guiding further investigation. In the samemanner, a clinical presentation suggestive ofDCPNESD will guide the investigation towards cer-tain specific mental disorders.

According to DMS-IV,12 patients with DCPNESDcannot be fitted into a single and specific diagnosticcategory. Mental disorders with dissociative andconversion symptoms, encompassing what was for-merly known as hysterical phenomena, are sepa-rated by DSM IV into the groups of somatoformdisorders (in which we find conversion, somatizationand undifferentiated somatoform disorders) anddissociative disorders (in which we find dissociativedisorder NOS). Moreover, post-traumatic stress dis-order, which may course with dissociative symp-toms, is classified in the group of anxietydisorders. DMS-IV does not clarify whether a patientwith post-traumatic stress disorder and dissociativesymptoms should or not receive an additional diag-

nosis of dissociative disorder. Moreover, it is unclearin DMS-IV whether a DCPNES in which there is dis-ruption of consciousness should be considered as adissociative or as a conversion phenomenon. In ourstudy, we adopted the criterion of classifying asdissociative all seizures that did not present anyother pseudoneurological manifestations besidesdisruption of consciousness. In Fig. 1 we schemati-cally present the nosological situation of DCPNESD inrelation to the classification of mental disordersproposed by DMS-IV.

In ICD-10,31 conversion and dissociative disordersare arranged into a single group solving some incon-sistencies presented by DSM-IV. According to ICD-10,patients with DCPNES would be entitled to be clas-sified under dissociative convulsions (F44.5). How-ever, some difficulties remain in DCPNESD caused bya somatization disorder, undifferentiated somato-form disorder, or post-traumatic stress disorder,since these would have an undefined diagnosticstatus, because ICD-10 does not explicitly mentiondissociative or conversion (pseudoneurological)phenomena in the description of these disorders.

Psychiatric comorbidities were frequent in oursample of PNES patients, with depressive disorderspresenting as the most frequent, in accordance withother studies.32

Conclusions

In conclusion, the observed data suggest that phy-siologic non-epileptic seizures and non-dissociative-conversion PNES are not clinically relevant for diag-nostic evaluation during intensive VEEG monitoring.On the other hand, DCPNES are the most frequentlyfound, representing the pseudoneurological mani-festation of a restricted group of mental disorders,that share some symptoms and that could tempora-rily, and for operational reasons be labeled asDCPNESD. However, great care should be taken,

Psychiatric diagnoses of patients with psychogenic non-epileptic seizures 253

because a significant portion of these patients dopresent epilepsy in association, and because occa-sionally these patients may present DCPNES as a denovo phenomenon during VEEGmonitoring while notpresenting de facto DCPNESD.

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