PREVALENCE OF DISSOCIATIVE SYMPTOMS AND DISORDERS WITHIN AN ADULT OUTPATIENT POPULATION WITH SCmZOPHRENIA John ~loise Pierre Leichner, M.D. John Moise was a medical student at Queen's University Medical School and an Extern at the Kingston Psychiatric Hospital in Kingston, Ontario, Canada at the time of this research. Pierre Leichner, M.D., is Psychiatrist-in-Chief at the Kingston Psychiatric Hospital in Kingston, Ontario, Canada. For reprints write Pierre Leichner, M.D., Psychiatrist-in? Chief, Kingston Psychiatric Hospital, P.O. Box 603, Kingston, Ontario K7L 4X3 ABSTRACT Objective: The objectives oj this study were to detennine the preva? lence ojdissociative symptoms and disorders in an adult outpatient population with schizophrenia and to study the relationship between dissociative symptoms and positive and negative S)'mptoms oj schizophrenia. Method: Consenting adult outpatients with schizophreniaJrom the Kingston Psychiatric Hospital in Kingston, Ontario, were administered the Dissociative Experiences Scale (DES). Patients scoring 25 or higher on the DES were interoiewed with the Positive and Negative Syndmme Scale (PANSS), and two intClviewsJor dissociative disorders: the Structured Clinical Interoiew Jor DSM-IV Dissociative Disorders (SCm-D) and the Dissociative Disorders Interoiew Schedule (DDIS). Results: 53 patients complet? ed the DES, and 14 (26%) scored 25 or greater. The scores on the DES subscale ojabs07ption and imaginative involvement wCl'e sig? nificantly highCl' than the scores oj the two other DES subscales, Jor both the group scoring>25 and alsoJor the study sample as a whole. The prevalence ojdissociative disorders in this population was esti? mated to be 9%, with dissociative amnesia the only dissociative dis? order diagnosed. The high DES scorers had a predominance ojpos? itive symptoms as evidenced &y a composite index score (positive symptoms score minus negative symptoms score) oj4.1, placing these patients at the 80th percentile, when compared to a nonnative pop? ulation ojpatients with schizophrenia. Conclusions: The finding oj consistently elevated scores on the absorption and imaginative involvement subscale ojtheDES in this sample suggests that the DES may not be a valid instrument to screm Jor dissociative disorders among patients with schizophl?enia. However, patients with schizophrenia who present with a predominance ojpositive symp? toms should be assessedJor the presence oja dissociative disorder. 190 INTRODUCTION Dissociative disorders are being recognized as increas? ingly significant psychiau'ic conditions (Ross, Anderson, Fleisher, & Norton, 1991; Saxe etal., 1993; Horen, Leichner, & Lawson, 1995; Eliason, Ross, Mayran, & Sainton, 1994). Not only is the primary diagnosis of dissociative disorders escalating, these disorders are also present as a comorbid condition in as many as 15-20% of adult psychiatric inpa? tients (Ross et aI., 1991; Saxe et aI., 1993; Horen et aI., 1995). However, with many patients receiving numerous different diagnoses prior to the recognition ofa dissociative disorder, the diagnosis of dissociative disorders is often overlooked or significantly delayed (Saxe et aI., 1993; Steinberg & Steinberg, 1994). Diagnosis of tl1ese conditions is compli? cated by the tendency for patients to present with symptoms which resemble other disorders, notably schizophrenia (Ross et aI., 1991; Saxe et aI., 1993; Steinberg, Rounsaville, & Cicchetti, 1990). Patients witl1 schizophrenia and those witl1 a dissociative disorder such as dissociative identity dis? order (DID - formerly multiple personality disorder) tend to present with Schneiderian first-rank symptoms. This leads to between 26-49% of DID patients receiving a prior diagnosis of schizophrenia (Gainer, 1994). Schneiderian first-rank symptoms include delusions, auditory hallucina? tions, thought insertion/witl1drawal, and feelings of exter? nal control of one's thoughts, feelings or actions. Recent evidence has shown that tl1e dissociative population may endorse these symptoms to a greater extent tl1an do schizophrenics (Eliason & Ross, 1995). In a study by Ross et al. (1990), 1739 schizophrenic patients possessed an aver? age ofl.3 Schneiderian symptoms each, whereas 368 patients witl1 dissociative identity disorder acknowledged an average of4.9 of these symptoms (Eliason & Ross, 1995). A recently published study, which examined the preva? lence of dissociative disorders in a Canadian adult psychi? atric inpatient population, found that 29% of patients pos? sessed dissociative psychopatllOlogy, and an estimated 17% of the patients had a diagnosable dissociative disorder based on clinical interview criteria (Horen et aI., 1995). However, a major problem with diagnosing dissociative dis? orders in schizophrenic inpatients was noted because these patients were often too symptomatic to be assessed proper- DISSOCIATION, Vol. IX, No.3, Septemberl996 1~ (Horen ct al.. 1995). This \\~d"i c\1dcnced b)' the finding that among lhe b.....oup of patients who anempted to com? plete Lhe DES. butga\c conU? tomatoIOb')'? The POSilh'c and Negati\'e Syndrome Scale (P.-\''\'SS) is a scmi~Ul.lClured intel"viewwhich produces scores from one (spnplOlll absclll) to s(','cn (severe spnptomatologv) 011 each of 30 items (K.?w, Opler. & Fiszbein. 1986: Kay, Opler. & Fiszbein. 1992). The thin}' items assessed by the I>Al'\SS are di\'ick'd into three sub-scalcs: positive spnptoms.slIch asdelu? sions and hallucinatory behaviour (7 ilems); negative s)'llll>? toms. including emotional wilhdnlwal and poor rapporl (7 items): and general psychopathology. such as anxiety and depression (16 items). A fourth subscale can be used which results from the posiuve minus negative scores. producing a compositc score \\'hich indicates the predominance of either positive 01' negative spnptoms (Kayel al .. 1992). The I>ANSS has been ev:aluaLCd for its reliability and \-alidit)' (Kay. Opler. & Lindcnma)'cr. 1988: Kar, Opler. & Lindenmarer. 1989: Bell et al.. 1992). Itllerrater reliability has been con? sistently measured ill 0.83-0.87 (Kar ct al.. 1988: Kar et al., 1989). Test-retcsi reliabilitv is assessed at 0.60, 0.68 and 0.80 for general ps)'chopathologY. negati"e, and posilive 5}'1111>? toms. respecli"e1y (Ka~ et aI., 1989). Internal reliability has lx.'cn measured at 0.73-0.83 (Karetal.. 1989). Both construct "3Iidi?\' and criterion-related validi'}' tests ha\'e also shown lhatthe PANSS is a sound instrument for lhe assessment of schizophrenic S\1nptoms, as indicated ",. high correlation to the Andreassen assessment measures (Eliason & Ross, 1995: Ka\ el al.. 1988). In order 10 ensure that lhe PA.'SS \\~dS implemented correcth'. the authors rC\;ewed the four hours ofPt'L,"SS rraining tapes and independentJ~ ratt."d the 191 PREVALENCE OF DISSOCIATIVE SYMPTOMS subjects. The ratings b)' the authors cOlTesponded to the \ideo responses either exactly (on mOSt items) or wil.hin one scale poinL The StnlCfUred Qinicallnteniew for DS.\I-ll'Dissociati\'e Disorders (SCID-D) was designed to measure five areas of dissoc::iali\'e S)mpLOms: amnesia. depersonalization. dereal? ization, identir)'confusion,and identityaltCrdtion (Steinberg clal., 1990). Foreach ofthese five sections. questioning srartS Ollt with open-ended screening items and progresses to spe? cific questions which ask the patient to describe the char? acter and frequency of the espoused spnptom (Steinberg el al .? 1990). TIle responses frolll each of the symptom areas are then scored on a scale from I (symptom absent) to 4 (severely symptomatic), gi\;ng a total score ranging from 5 to 20. This measure is the first designed to enable an inter? viewer to make a diagnosis of a dissochlti"e disorder (Steinberg et al.. 1990). The SCID?,Q has good-to-excellenl validity and reliability for the detection and diagnosis ofdis? sociati"e S)'mptoms and disorders (Steinberg & Steinberg, 1994). The final inSl.n..lmem employed in this study is the Dissociative Disorders Imeniew Schedule (0015). As .....ith the SCJ[)'O, the 0015 is designed to give a 05:-'1 diagnosis for dissociative disorders (Ross et at., 1990). For diagnosis of dissociati"e identity disorder (OlD). intenater reliabilit}' is 0.68, sensiti'il}' is 90% and specificity is 100% (Ross et al.. 1990). Unlike the SCJD-D, the ODiS provides additional OS:-'l diagnoses of somatization disorder. major depression, and borderline personaIit}' disorder ifan}' or all of these are pre? sent. The ODiS also includes questions on areas associated with dissociative disorders such as Schneiderian symptoms, childhood physical and/or sexual abuse, and secondary fea? turesofDID (Ross et aI., 1990). Thus, the DDIS and SCID-D sen:e to complement each other in the detection and diag? nosis of a dissociative disorder. Patient information collected included: age, gender, education !L"\'c1, marital status, time since first hospital con? laC!, and primary diagnosis. This information .....?dS given by the subjects and verified from hospital records. DATAAJ"'JALYSIS For the purposes of this project, the outpatient schizophrenic population for Kingston PS)'chiatric Hospital (KPH) .....as di'ided into two groups. First, the study group .....as compost:d of the patients approached when they pre? sentrd to each of three Kingston psychiatric hospital out? patient senices m'er a three month period (n:53). The study group "''as further broken do",,, into those who scored 25 or higher (high scorers) "ersus those who scored less than 25 (10..... scorers). Second, the control group "''as composed of all patients ""ho ",'ere not contacted or refused to partic? ipate (n=193). Due to the small number of patients who refused to participate in the study, they were not considered separatclyfrom the patients who were not con laC ted. Where 192 appropriate. group comparisons were tested using /\,"OVA or tw!>-tailed Hests. RF.SULTS Samp/~ There were 246 people registered as outpatients in the schizophrenia rehabilitation senice at KPH. Permission "'as granted to approach each of these patients, ofwhoIII 65 "'ere contacted (only 65 were conL.'lcted due to the large catch? melH area of KPH and tJ1e resulting infrequent ,isits b)' a moyority of these patients). Of these 65 patients, 58 (89%) consented to complete the DES. Howe\"er, upon chan review, it was determined that five of these patients had pri? mary diagnoses other than schLwphrenia, and were, there? fore, excluded from the stud)' So'lmple. The 53 patients with schizophrenia who completed the DES comprised the study group. Se"emeen (32%) of IJle 53 within the study group were female, and 36 (68%) were male. Group Comparisons Demographic information used to compare the Slud)' 531111)le (1':=53) with the remainder of the outpatient group (N:193) are displared in tJ1e first two columns of Table 1. There "''as no statistical difference between tJle groups for gender, marital status, education, and schizophrenic diag. noses. HowC'?er, the stud)' group proved to be )?ounger (x: 41.6 years) than the nonoStudy group (x = 47.0 rears) (p.o.()() I). DES Results The mean DES score for the studygroup was IS.7 (range 0.0 - 61.1). Fourteen (26%) of tJle patients scored equal to or greater than 25 on the DES. Females comprised 33% of the group scoring <25 and 29% of the group scoring >25. For the low scorcrs ?25), the lUcan score was 10.7 (range 0- 22.0). The mean DESsubscale scores for this group were: 5.7 for the amnestic subscale, 7.0 for the depersonalization/ dercali7.ation subscale, and 15.7 for tJle absorption and imag? inative inmh?emem subscale. For the high scorers (>25), the mean DES score was 40.7 (range 25.4 - 61.1). The mean DES suhscale scores for this group ",'ere 33.0 for the amnestic sub? scale, 35.3 for the depersonalization/ derealization subscale. and 51.7 for the absorption and imaginative inmlvemem subscale. PANSS &suIts Of the 14 patients "'ho .scored >25 on the DES, three refused funher inteniCY.'S, and one W"dS lost to follow up. The remaining ten patienlScon.semed to participate in the PA,"SS intcn;ew. The mean lotal score "'as 70.3 (range 49 - 90). The PANSSrating manual suggests lhat the total score is beSt used as a measure of patient response lO therapy, whereas . the individual subscores give T-scores which allow compar' ison to a normali,?c population of240 schizophrenics. The DIS.'iOCl-\.TIOX. \01 IX. \ ?. 1 SrptnIbrrl!* MOISE/LEICHNER TABLE I Demographic Variable Among Patients with Schizophrenia in Study Sample. Non-5LUdy Sample and Low and High Scoring Croups on Dissociative Experiences Scale (DES) Variable Study Non-Study DES Score DES Score Variable Description Sample Sample <25 >= 25 N (%) N (%) N (%) N (%) To"" 53 193 39 14 Gender Female 17 32.1% 71 36.8% 13 33.3% 4 28.6% ~'Iale 36 67.9% 122 63.2% 26 66.7% 10 71.4% Age Range 2%1 20-76 2%1 26-51 Mean 41.6 47 42.2 39.8 SD 9.2 12 9.7 7.8 Marital Single 38 71.7% 120 62.2% 26 66.7% 12 85.7% S13"'" Married/Common Law 6 11.3% 26 13.5% 4 10.3% 2 14.3% Divorced/Separated 9 17.0% 40 20.7% 9 23.1% 0 0.0% Olher 0 0.0% 7 3.6% 0 0.0% 0 0.0% Education None/Unknown I 1.9% 12 6.2% 0 0.0% I 7.1% Elemenlal')'-SOme/comp. 6 11.3% 38 19.7% 4 10.3% 2 14.3% Secondarr-some/comp. 36 67.9% 109 56.5% 26 66.1% 10 71.4% POSt Set:ondaf}-some 8 15.1% 18 9.3% 7 li.9% 1 7.1% Post Sei:ondat')"-eomp. 2 3.8% 16 8.3% 2 5.1% 0 0.0% Diagnosis Schizophrenia'paranoid 18 34.0% 66 34.2% 11 228.2% 7 50.0% Schizophrenia-residual 10 18.9% 60 31.1% 8 20.5% 2 14.3% Schizoaffectivc 12 22.6% 26 13.5% 11 28.2% 1 7.1% Schizophrcia-olhcr 13 24.5% 31 21.2% 9 23.1% 4 28.6% posil.i\?e subscale mean "'dS 18.1 which gives a T-score of47, and translates to the 38th percentile for schizophrenics (Kay. Opler. & Lindenmeyer. 1992). The negative subsca.le mean ....'as 14.0, T-score 38, corresponding to the 12t1l percentile (K"'yet al., 1992). The mean composite SCOfe (the mean of the positive minus the negative scores) was 4.1 (T-score of 58, 80lh percemile) (Kay et al., 1992). The mean general psychopatholog)' score of 39.2 gives a T-score of 49 which lies at the 46th percentile (Ka}' et al.. 1992). Dissociative Disordn-s lntnviews Ofthe ten patienrswho panicipated in the PA..~SS inter? \ie....'S., six consented tocontinue ....ith both tile OOiSand SCI~ o imeniews. DDiS Non~l.issociativefindings: Of the six patients who com? pleted the ODIS imeniews: none had somatization disorder, two were positive for subsl.mce abuse, three met the cril.e? ria for a major depressive episode, one had a hisl.ory ofchild? hood physical abuse, none had a history of childhood sex? ual abuse. and three mel OOIS crileria for borderline personality disorder. Dissociative Findings Fouroflhe six patients (66%) met ODIS criteria for dis? .sociati\?e amnesia. None met the diagnostic criteria for dis? sociative fugue, depersonalization, dissociative identity dis? order or dissociati\'e disorder nOI ol.heruise specified. 193 DISSOO%TIO.... \.a.1X. ~.. 1 Srpct*rIMi PREVALENCE OF DISSOCIATIVE SYMPTOMS SCID The SCID-D interviews proved to be critical in deter? mining the presence ofdissociative disorders. From the DDIS interviews, four subjects met criteria for dissociative amne? sia. However, this criterion is restricted to the subject responding positively to the question: "Have you ever expe? rienced sudden inability to recall important personal infor? mation or events that are too extensive to be explained by ordinary forgetfulness?" A positive response must also not occur due to a known physical disorder (e.g., blackouts dur? ing alcohol intoxication, or stroke). The difficulty with the DDIS is that this question is both subjective and difficult to interpret as being a sign of dissociative amnesia without fur? ther follow-up questions which are not possible wid1in the rigid structure of the DDIS. This is where a second dissociative interview proved to be important. With d1e SCID-D, two of the four patients who described during the DDIS interview as having extensive memory loss proved to have difficulties in concentration which were not due to dissociative amnesia. One patient described: ''When I talk I sometimes forget what I want to say." The second patien t described forgetfulness which was not extensive. Bod1 of these patients scored the lowest possible value for the amnesia subscale of the SCID-D I (absent) outof4. However, two of the four subjects had extensive memory loss which extended for hours or days and occurred frequendy, lead? ing to a score of 3 (moderate) and 4 (severe) on the SCID? Dsubscale ofamnesia. Thus, two out ofthe six patients (33%) met both DDIS and SCID-D criteria for a diagnosis of disso? ciative amnesia. Three of d1e six patients who participated in the SCID-D in terviews were given a score offive out of twen? ty, which corresponds to all five of the symptom areas being normal. The final participant received a moderate score (ili,-ee oUloffive) for bcfth depersonalization and for dere? alization; however, d1ere was no evidence of a diagnosable dissociative disorder. DISCUSSION This study set out to accomplish two goals. The first was to determine the prevalence of dissociative symptoms and disorders in a population ofschizophrenic outpatients. The second objective was to correlate dissociative symptoms and positive/negative schizophrenic symptoms. However, one limitation to this study was that the high number of patients who refused to be interviewed after the PANSS resulted in a small sample for DDIS and SCID-D interviews (n=6). This pre? sents difficulties in determining precisely who amongst the high DES scorers had diagnosable dissociative disorders. However, the significant number of those intervieweq with the DDIS and SCID-D who had a dissociative disorder (33%), supports ilie position iliatschizophrenia and dissociative dis? orders may coexist. The presence ofdissociative psychopathologywiiliin this 194 outpatient schizophrenic population is estimated to be 26%, based on a DES score of25 or higher. Evidence for d1e gen? eralizability of this figure comes from the finding that the mean DES score of 18.5 (n=53) in this study matches very closely to that given by Carlson and Putnam (1993) in a dif? ferent schizophrenic population which demonstrated a mean score of! 7.7 (n=61). A1dlOugh this value of26% does not indicate d1e percentage ofschizophrenics wid1 diagnosed dissociative disorders, ilie significant proportion of patients who suffer from these ymplOms is cause to evaluate what is being done to help these patients with these symptoms. Of the 14 (26%) of patients who reported having dissociative symptoms, only six consented to furd1ertestingwith the DDIS and SCID-D diagnostic interviews. This low compliance is rec? ognized as a limitation of this study. However, this was a daunting process for this group, of which the largest pro? portion were paranoid schizophrenics. None the less, ofd1e six who completed all four tests, two (33%) met DDIS and SCID-D criteria for dissociative amnesia. This value extra? polates to approximately 9% of the schizophrenic outpatients having a dissociative disorder as a comorbid disorder. An unexpected finding of this study was the relatively low prevalence ofchildhood sexual abuse in this population. Only one of ilie six (17%) patients two females and four males who completed all four of the psychometric tests had a history of childhood abuse. This male patient was physi? cally abused but not sexually abused. In psychiatric outpa? tients, the prevalence of sexual abuse has been estimated from 50% to 65% (Palmer, Chaloner, &Appenheimer, 1992; Waldinger, Silvett, Frank, & Miller, 1994) for females and 25% for males (Smiili, Hutchings, & Dutton 1993). However, most of these patients were not diagnosed with schizophre? nia. One study that included 46% of women patients with schizophrenia reported 45% of the sample had been sexu? ally abused and that these women had higher levels of psy? chotic symptoms (Mvenzenmaier, Meyer, Struening, & Ferber, 1993). Our sample of interviewed outpatients with schizophrenia reported a lower prevalence ilian that ofoilier studies. We can only speculate that this may be due to the relatively low number of females in this sample and/or that d1is may be a higher functioning group. Our finding of no cases of DID follows from this observation as almost all patients with DID have histories of childhood abuse (Ross et aI., 1990). Results from ilie analysis of the DES subscales demon? strate that one of the subscales (absorption and imaginative involvement) is significantly higher than either of the two other subscales. This difference is maintained amongst all of ilie groups: the study group as a whole, the low scoring group (DES mean <25), and the high scoring group (DES mean 25 or greater). This finding is highly suggestive that the nature of the dissociative symptoms experienced by patients wiili schizophrenia is one of increased absorption in their surroundings and a greater tendency to be involved DISSOCIATIO:\, Yo!. IX. :\0. 3, Septemberl996 ,,;th their imagin:uhc life. Without the scores from Lhissub? scale. the DES scores for this schizophrenic population are drnsticall" Im?ocr. For the cmire brrouP. the subscalc score for depersonali/...ation derealization is 14.3. and for amnes? tic dissociation il is 12.6. These are both dearly Im,'cr than the mean subscale score of 24.7 for ab:.orplion and imagi? native invoh'cmenl. Thisfindingsubrgcsts thaI there are qucs? (ions on the 01':.5. spccificall)'those related loabsorplion and imaginative illyoh'cment. which mOl)' be poorl)' suited to dis? criminate between schizophrenia and dissociative disorders. This might have .Htribllu~d to the dinicuhies encountered in the SUld\" b\' Horen et OIL (1995) in assessing Ihe schizophrenic population for dissociative doorders. One slUd\ ~ Ross el al. (19 ) recognized Ihal due to Ihe sig? nifiC31l1 o\'erlap between schizophrenic and dissocialiw: S\mploms on the DES. a shan fonn ohhe DES might be mOl'e discriminati\'e when ""orking"';th schizophrenic populations (Ro~. Nonon. & Anderson. 1988). This sllld} indicates thaI perhaps elimination or modification of the DES subscale involving absoqltivc and imaginative in\"Ol\'emenl might fI\.'\SS inlen'iew. The results showed Ihallhe dissociative idelllity palients receh'ed a composite score of7.2 \'ersus a composite score of ?1.9 for thc schizophrenic population. Thus, palient.'i \\'ilb dissoci,,? tive identily had Chizophrenia are caused by dissociation. Allhough il may bc slretching Ihe poilll 10 suggesllhat dissociati\'c experi? ences arc Ihc sole, or even the primal)' etiologic agenl for Schneiderian symploms. Ihere remains the possibility thaI for some patienls with schi.wphrenia. posili\'e symptoms might be exaccrbated by dissociation. In conclusion, lhisSIUd}' has shown that asignificant per? centage ofpalicnts diagnosed wim schil.ophrcnia lIla\ ha\'e dissociati\"e PS\-ChOpalholog'l (26%). and these patients tend to pl"esclll ",;th a high number of positi\'e S\lllploms. Furlher conclusions from lhis imestigation are: First. mat Ihe DES ma, need to be modified to better discriminate between dissociati\"e disordcrs and schizophrenia and that cauuon should be used in interpreting high DES scores in Ihis population as indicali\c of dissocialive disorders. Secondl}'. th;1I schizophrenic patients who present with a pre? dominance of positi\'e S)mptoms should have a possible comorbid dissociative disorder considcred. To further understUf Mt"Ilal D/.SfflSl!. /83(4),231?235. Ellason.j. W.. & Ross. G.A_ (1995). Positi,c and negali\"e ~'mptoll1s ill dissodatil'c idcnliT}' disorder and schizophrenia: A compar:ui\'c analrsis. journ(ll oj.\'mlQus and j\ImIaIOlSMY. 183(4), 236-2<1 I. ElIason. j.W.. Ross, C.:\., .\Ia\'ran. L\\".. & SaimoJl. K. (1994). Comerge11l \'alidit\ of the nc.... fonn ofthe DES. OfSS(XY. TlO.\, i(2). 101?103. 195 DI5SOCl\TIO\. \01. IX. \ ..1~1'" PREVALEJ"~"CE OF DISSOCIATIVE SYMPTOMS Gainer, K. (1994). 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