feeling unreal cognitive processes in depersonalization

7/29/2019 Feeling Unreal Cognitive Processes in Depersonalization

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Am J Psychiatry 157:1, January 2000 103

Feeling Unreal:Cognitive Processes in Depersonalization

Orna Guralnik, Psy.D., James Schmeidler, Ph.D., and Daphne Simeon, M.D.

Objective: Depersonalization disorder is characterized by a detachment from ones

sense of self and ones surroundings that leads to considerable distress and impairmentyet an intact testing of reality. Depersonalized individuals often report difficulties in percep-

tion, concentration, and memory; however, data on their cognitive profiles are lacking.Method: Fifteen patients with depersonalization disorder were compared to 15 matched

normal comparison subjects on a comprehensive neuropsychological test battery that as-sessed cognitive function. Results: The subjects with depersonalization disorder showed

a distinct cognitive profile. They performed significantly worse than the comparison sub-jects on certain measures of attention, short-term visual and verbal memory, and spatial

reasoning within the context of comparable intellectual abilities. Conclusions: The authorspropose that depersonalization involves alterations in the attentional and perceptual sys-tems, specifically in the ability to effortfully control the focus of attention. These early en-

coding deficits are hypothesized to have a deleterious effect on the short-term memorysystem; they manifest as deficits in the ability to take in new information but not in the ability

to conceptualize and manipulate previously encoded information.

(Am J Psychiatry 2000; 157:103109)

Depersonalization is characterized by a detachmentfrom ones sense of self and ones surroundings and afeeling of being an automaton or as if in a dream whilemaintaining an adequate testing of reality. Individualsmeet the criteria for depersonalization disorder if theysuffer from persistent or recurrent depersonalizationsymptoms that lead to significant distress or dysfunc-tion and do not occur exclusively as part of anotheraxis I disorder. Despite an increased interest in dissoci-ation in recent years, not much is known about the eti-ology, course, prevalence, and incidence of depersonal-ization. Some reports suggest it may be the third mostcommon psychiatric symptom after depression andanxiety; however, it is highly resistant to both psycho-therapeutic and pharmacological treatment (1). Deper-sonalization is classified in DSM-IV as a dissociativedisorder. Although there exists an impressive theoreti-

cal literature on dissociation, there have been few em-pirical attempts to substantiate theoretical models. Theclinical literature is mostly concerned with establishingthe premise that dissociation functions to protect theself from overwhelming emotional experiences andviews dissociative disorders primarily as a response totrauma (2). In the nineteenth century, Janet (2) de-scribed dissociation as a narrowing of attention and adisorganization in the ordinary integrative functions ofconsciousness that occur when a person experiencesvehement emotions. Since then, long-lasting alter-ations in cognitive processes in response to traumahave been documented (3). However, it is unclear atwhat stage of information processing dissociationtakes effect and whether it involves alterations in theinitial stages of encoding information, while it is beingoverwhelmed by trauma, or is reflective of later amne-sic barriers to the retrieval of information.

Neodissociation theories (4, 5) view dissociation asreflective of mechanisms that all people use to varyingdegrees. Their central premise is that dissociation in-volves a weakening of the highest-order executive con-trol functions that leave infrastructures more freedomto operate independently. Strong activation of the ex-ecutive system has the experiential equivalent of con-centration, consciousness, and self-hood, whereasits weakening results in the emergence of the mindsunderlying inherently dissociated nature. Hilgards fa-

Received Nov. 20, 1998; revision received April 5, 1999;accepted June 10, 1999. From the Department of Psychiatry,Mount Sinai School of Medicine. Address reprint requests to Dr.Guralnik, Mount Sinai School of Medicine, Box 1228, OneGustave L. Levy Place, New York, NY 10029; [email protected] (e-mail).

Supported in part by a National Alliance for Research on Schizo-phrenia and Depression Young Investigator Award to Dr. Guralnikand NIMH grant MH-55582 to Dr. Simeon.

The authors thank Bonnie Aronowitz, Ph.D., and Philip Harvey,Ph.D., for help in compiling the assessment battery and LauraFink, Ph.D., for her comments on the article.


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mous documentation of the hidden observer phe-nomenon in experiments that involved hypnotically in-duced analgesia and deafness is particularly illustrativeof this theory (4). Operationalizations of these theoriesrest on the prediction that the ability to dissociateshould facilitate performance on dual-task situationssuch as divided and selective attention. However, stud-

ies have failed to show differences between hypnosis-prone and comparison subjects on task-interferenceconditions (6). Many of these experiments rely on thepremise that proneness to hypnosis is a reliable markerof dissociation proneness, whereas it appears that onlya small subgroup of people are both highly dissociativeand highly hypnotizable (6). Waller et al. (7) have ar-gued that pathological dissociation is a categoricaltaxon rather than a continuous entity, which impliesthat normal populations would not be applicable tostudies of dissociative disorders.

Several studies have examined the relationship be-tween dissociation and cognitive functioning in patientswith dissociative identity disorder. These mostly point

to deterioration and excessive scattering of interest onintelligence tests, with some signs of neuropsychologi-cal deficits on distractibility measures (8, 9). There wasone early study (10) that compared the cognitive func-tioning of depersonalized subjects to matched depres-sive and anxious patients in which tests of psychomotorabilities did not differentiate between the groups. Oth-erwise, to our knowledge, there has been no systematicstudy of the cognitive profile involved in depersonaliza-tion to date. Assessing this profile was the purpose ofthis study. Since neodissociation theories implicatechanges in executive control functions and memory,and since patients subjective reports include disrup-tions in attention and memory, we decided to focus par-ticularly on those areas in the context of general intel-lectual functioning. Our hypotheses were that thedepersonalized group would show deficits in function-ing on measures of attention and memory in relation tothe comparison group but that it would exhibit uncom-promised intelligence on the WAIS-R.

METHOD

Subjects

Fifteen subjects with DSM-IV depersonalization disorder and 15comparison subjects were recruited through local newspaper ads.

The depersonalized subjects were enrolled as part of a larger, ongoingtreatment study. The comparison subjects were paid $75 each forparticipation. Written informed consent was obtained from all sub-jects. The subjects were aged 1865 years. The comparison subjectshad no lifetime history of axis I or II disorders, as assessed by theStructured Clinical Interview for DSM-IV Axis I Disorders, PatientEdition, version 2 (11), and the Structured Interview for DSM-IV Per-sonality (12). The subjects with depersonalization disorder met theDSM-IV criteria for depersonalization disorder by a semistructuredinterview and by the Structured Clinical Interview for DSM-IV Disso-ciative Disorders, revised (13). Subjects with lifetime psychotic disor-ders or current substance use disorders were excluded. No subjectshad taken any medications for at least 5 weeks before testing. Peoplewith a history of medical or neurological disorders were excluded.

Measures

A 6-hour test battery, to be described, examined the subjects gen-eral intelligence, attention, and memory. A single licensed clinicalpsychologist (O.G.) administered all the neuropsychological mea-sures and strictly followed the test manuals standardized adminis-tration procedures.

The WAIS-R (14) is the most widely used adult intelligence test. Ityields IQs for verbal, performance, and general intelligence. Admin-istration and scoring are standardized, and extensive normative dataare provided.

The Wechsler Memory ScaleRevised (15) is widely used to eval-uate verbal and visual-spatial memory and is particularly sensitive tosubtle memory disorders (16). Administration and scoring are stan-dardized, and normative data are provided. In this study, we usedonly measures of immediate recall.

The Stroop Color-Word Test (17) is a widely used measure that issensitive to subtle neuropsychological problems in attention (18).

The emotional Stroop task (19) is gaining popularity in psychiat-ric research and has been applied to the study of various disorders toassess the interference of emotional material with selective attention.Subjects are shown words of varying affective significance and areasked to name the colors in which the words are printed and to ig-nore the meaning of the words. Patients are often slower to name thecolor of a word associated with concerns relevant to their condition.

In this study, we included four lists: a neutral list (e.g., carpet, tree),a negative affect list (terror, rage), a positive affect list (ecstasy, ela-tion), and a list of depersonalization-related words (dreamy, spaced).The lists were presented in the order used here, against our workinghypothesis. The dependent variable was time for completion of read-ing the list.

We added an incidental learning component to the emotionalStroop task. One minute after the administration of all four lists, thesubjects were asked to recall all words on the lists and were encour-aged to guess. It is established in the literature that mood-congruentmemory biases are more evident on implicit memory tasks (20); thepremise is that the learned information changes perceptual responsesystems without being accessible to conscious recollection.

Trail Making Tests A and B (21) are known as measures of atten-tion, visual-motor and sequencing skills, and cognitive flexibility.They are sensitive to the presence of brain damage and do not corre-late with verbal tests (22).

The Wisconsin Card Sorting TestComputerized Version (23) iswidely used in psychiatric research to measure conceptualization,executive functioning, and set shifting. It discriminates well betweenbrain-damaged and comparison subjects (23).

The Facial Recognition Test (24) taps complex visual-spatial pro-cessing that is independent of memory. It is sensitive to visual neglectand other forms of visual-spatial and visual-search difficulties (22).

Vigils Continuous Performance Test (25) is a computerized atten-tion test that taps attention and impulsivity. Briefly, this version in-volved the successive presentation of letters on the screen of a com-puter monitor. In the standard administration, subjects are presentedwith four conditions. In the first (K), a series of letters are projected,and the subject is to respond when he or she sees a target letter (K).The next condition (AK) is complicated by the added instruction torespond only if the target letter is preceded by a decoyanother let-ter (A); this task is more demanding in that it requires memory forsuccessive stimuli. In the last two conditions, the first two conditions

are repeated with the addition of visual noise in the form of smallpixels on the screen (AN and AKN, respectively). The addition ofnoise degrades the image and burdens early stimulus analysis and en-coding processes. For each conditions number of responses and cor-rect hits, omission and commission errors are recorded.

Data Analysis

All neuropsychological test scores, except for scores on the Con-tinuous Performance Test, were compared in the two groups by useof Students independent t tests. Since our hypothesis was that thedepersonalized group would perform poorer than the comparisongroup, significance tests were one-tailed; Bonferroni correctionswere employed according to the number of subtests and summary


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GURALNIK, SCHMEIDLER, AND SIMEON

scores within a test (family of hypotheses). The family and number

of corrections for each comparison are explicated in the footnotesof the tables. For each subject, the standard deviation among the 11standardized subtest scores of the WAIS-R was calculated as a mea-sure of intertest scatter. Groups were compared on this measure byuse of Students t tests. In order to rule out the confounding effectsof gender, a two-way analysis of variance (ANOVA) (diagnosis-by-gender) was applied to test scores to assess interaction effects. Twoseparate analyses were performed on the Continuous PerformanceTest. The first examined evidence of a differential decline betweenthe groups in attentional performance over time. Each of the fourconditions (A, AN, AK, and AKN) was divided into four blocks ofequivalent time, and the numbers of omissions and commissionswere analyzed by a 244 (group-by-decoy-by-block) repeatedmeasures multivariate analysis of variance (MANOVA). In the nextanalysis, to compare the groups functioning on each of the condi-tions, the time blocks were collapsed so that each condition was

represented by its average. A four-way repeated measures ANOVAwas employed, with group as the between-subjects independentvariable and decoy (A or AK), distraction (noise or no noise), andtype of error (omissions or commissions) as the within-subject inde-pendent variables. After the analyses, all statistically significant (af-ter use of the Bonferroni correction) differentiating variables wereentered into a forward stepwise logistic regression analysis to deter-mine which variables were the most powerful in distinguishing thegroups.

RESULTS

Demographic Variables

The groups did not differ significantly on sex (deper-sonalized: five women and 10 men; comparison: ninewomen and six men) (2=2.14, df=1, n.s.), age (deper-sonalized: mean=32.2 years, SD=8.6; comparison:mean=29.0, SD=7.4) (t=1.1, df=28, n.s.), or education(depersonalized: mean=16.0 years, SD=2.2; compari-son: mean=16.1, SD=2.5) (t=0.2, df=28, n.s.). Whenwe used a 22 ANOVA, we found no interaction ef-fects between diagnostic group membership and gen-der on any of the variables assessed. All but one of thecomparison subjects were right-handed.

Intellectual Functioning

WAIS-R scores and comparisons are summarized intable 1. In comparison to existing norms, the IQs forthe comparison group were within the average range.The groups did not differ on IQs. Whereas the compar-ison group scored a substantial difference of 10 pointshigher than the depersonalized group on performanceIQs, this difference was not significant after use of theBonferroni correction. The depersonalized group had alarge discrepancy between verbal and performance IQs(an average 14-point difference, as opposed to nearzero in the comparison group), but the depersonalizedsubjects did not differ from the comparison subjects onintertest scatter. Of the 11 WAIS-R subtests used, the

depersonalized group scored significantly lower onblock design.

Scores on the Wechsler Memory ScaleRevised, Fa-cial Recognition Test, Stroop Color-Word Test, andWisconsin Card Sorting Test are summarized intable 2. The groups did not significantly differ on theWisconsin Card Sorting Test, a measure of executivefunctioning and flexible problem solving. On theWechsler Memory ScaleRevised, the depersonalizedgroup had significantly worse scores on the generaland visual memory summary measures and on the log-ical, figural, and visual paired memory subtests. Onthe incidental learning addition to the emotionalStroop task, the depersonalized subjects had a signifi-cantly superior recall for words related to depersonal-ization. A closer look reveals that they also had a bet-ter memory for negative words and overall recalldifferences that were not significant after use of theBonferroni correction.

Scores on the Continuous Performance Test re-vealed that on the repeated measures MANOVA,there were no effects of the time-by-group or time-by-condition-by-group interaction, which revealed novigilance decrements over time that were unique to thedepersonalized subjects. A four-way ANOVA was em-

TABLE 1. Scores on the WAIS-R for 14 Patients With Depersonalization Disordera and 15 Normal Comparison Subjects

WAIS-R Item

DepersonalizationDisorder Group Comparison Group Analysis

Mean SD Mean SD t (df=27) p

IQFull 105.5 9.8 109.4 11.9 1.0 0.17Verbal 111.2 9.8 108.6 10.9 0.7 0.25Performance 98.4 10.6 108.6 11.9 2.4 0.01

Information 11.7 2.3 11.8 2.3 0.2 0.44Digit span 11.4 2.1 11.7 2.5 0.4 0.36Vocabulary 12.6 1.7 11.3 2.1 1.7 0.05Arithmetic 10.6 2.9 11.1 2.5 0.5 0.30Comprehension 11.7 2.0 11.4 2.7 0.4 0.34Similarities 11.9 1.6 10.8 2.4 1.3 0.09Picture completion 10.2 2.2 10.8 2.1 0.7 0.23Picture arrangement 9.2 1.9 9.9 1.9 0.9 0.19Block design 9.8 2.4 12.8 2.8 3.1 0.003b

Object assembly 8.9 2.6 10.4 2.4 1.6 0.06Digit symbol 10.4 1.9 11.8 1.9 1.9 0.03a One subject with depersonalization disorder was not given the WAIS-R.b Significant after Bonferroni corrections for 14 comparisons (p


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ployed to test the hypothesis that distracters wouldmore deleteriously affect the subjects with depersonal-ization disorder. The group main effect was signifi-cant; the depersonalized group had more errors thanthe comparison group (F=4.82, df=1, 26, p


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ception, attention, and memory. The groups compara-ble general intellectual functioning is crucial for the in-terpretation of the rest of the findings in suggestingthat depersonalized subjects do not demonstrate thegeneral and diffuse deterioration in functioning that isoften seen in conjunction with psychiatric disorderssuch as schizophrenia or depression (26). The groups

did not differ in various measures of sequencing or re-action time that could intimate a disorganization or aslowing down of cognitive processing.

The depersonalized subjects did, however, demon-strate clear impairments on visual-spatial tasks. Theydid poorly on some performance tasks of the WAIS-Rsignificantly so on a measure of spatial reasoning(the block design subtest). The block design subtestscore was the single best predictor of diagnostic groupmembership in the regression analysis; it emphasizedthe importance of this factor in differentiating betweenthe groups. Attributing this impairment to problems invisual-motor coordination should be ruled out since thegroups did not differ on scores on graphomotor tests

such as the digit symbol subtest, Wechsler scale visualreproduction subtest, and Trail Making Tests A and B.The materials used in the block design subtest are three-dimensional cubes, which is of great interest since dep-ersonalized subjects often report a subjective flatteningof their visual-perceptual world into two dimensions. Itis not uncommon for them to have been referred forpsychiatric help after consultations with ophthalmolo-gists, whose standard examinations yielded no findings.In fact, on the Wechsler scale, depersonalized subjectshad difficulties on tasks involving memorizing geomet-ric figures (the figural memory subtest) and pairs of col-ors (the visual paired association subtest)both ab-stract visual stimuli. These findings lead us to conclude

that depersonalization is associated with deficits in vi-sual perception and visual-spatial reasoning with boththree- and two-dimensional stimuli.

Comparable scores of the groups on the WAIS-R in-formation and vocabulary subtests imply that deper-sonalized subjects do not suffer from gross impair-ments in long-term-memory. They also did well onvarious verbal short-term memory tasks, including theincidental learning test, digit span, and verbal pairedassociation memory subtestsall sensitive to learningdeficits that involve complex or novel information.However, the depersonalized subjects did much worsethan the comparison subjects on the logical memorysubtest; the test is unique in that it employs sentencesrather than words and provides a measure of what isretained when more information is presented thanmost people can remember. Thus, the depersonalizedsubjects short-term verbal memory capacity tended tosignificantly drop in relation to that of comparisonsubjects when it was presented with an overload ofinformation.

So far it is apparent that depersonalized subjectsdemonstrate certain compromises in both visual andverbal short-term memory with stimuli of both an ab-stract and meaningful nature. It is still questionable

whether these deficits can be attributed to difficultiesin taking in new informationi.e., in perception andattention or in retrievalalthough the subjects ade-quate long-term memory supports the former. One ofthe symptoms that they describe is a disruption in theirsense of familiarity with both themselves and their sur-roundings. Although they know better, they feel as if

all is new, whereas their self is at an unbridgeable dis-tance from ongoing perceptions. The blunted sense offamiliarity could blatantly compromise their function-ing on memory tasks that rely on recognition. Supportcomes from the fact that many of their visual percep-tion and discrimination problems were not apparentwhen the stimuli were right in front of them, as in theFacial Recognition Test.

One of the key findings in this study is the deperson-alized subjects impaired functioning on the Continu-ous Performance Test. The features of attention thatare targeted in this test are the ability to selectively at-tend to the stimuli presented and the ability to sustainattention, as measured by decrements in functioning

over time. Depersonalized subjects showed significantdeficits only when visual noise was addedin responseto which they tended to have more omissions, as op-posed to an increased rate of false alarmsand did notdiffer in their ability to sustain attention over time. De-grading stimuli are among the methods used to isolatethe stimulus-encoding, information-processing stage,as opposed to the response-selection and organiza-tional stages. The addition of noise lowered the sub-jects perceptual sensitivity, which made it difficult forthem to rapidly extract relevant stimulus features. Thefindings so far suggest that depersonalization ismarked by a particular vulnerability at the level of per-ception and attention. Deficits in short-term memory

could be, therefore, secondary to difficulties focusing,perceiving, and taking in new information.

Unlike we predicted, on the emotional Stroop task,the depersonalized subjects did not demonstrate moreinterference effects; they were therefore different fromother clinical groups, such as patients with panic disor-der and posttraumatic stress disorder, who reportedlydemonstrate a strong attentional bias on the emotionalStroop task (19). Their superior incidental learning testscores revealed that they did not ignoreand actuallyrememberedmore emotionally charged words thandid the comparison subjects; unnecessary informationcould potentially disrupt their task. Clearly, they canbe highly perceptive and demonstrate good memoryat least when the information is of emotional signifi-cance to them. Possibly, their internal preoccupation isat the expense of allocating resources toward other as-pects of their environment. Their awareness of thesewords weakens the hypothesis that their dissociativesymptoms serve a defensive function and can be inter-preted from a psychodynamic and structural point ofview as a failure in repression. Repression is posited todefend the ego from anxiety-provoking information bymaking such material unavailable to conscious percep-tion. Although both mechanisms aim to ward off pain,


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dissociation differs in that it involves a splitting off ofwhole chunks of experiences or self-states, which leadsto an altered state of being, whereas repression is amore selective riddance of information and, in that re-spect, can be more adaptive. This issue will need to befurther studied.

When we integrated some of our findings, it ap-

peared that on the Continuous Performance Test, thedepersonalized patients exhibited difficulties attendingto target stimuli in the presence of noise; this is a taskthat involves selective attention. On the emotionalStroop task, they attended to irrelevant and potentiallydisruptive information. Our interpretation is that theyfind it difficult to willfully control and direct attentiontoward the key features of the stimulus. In terms of theneodissociation theory, the depersonalized subjectsfunctioning on the emotional Stroop task and the inci-dental learning test supports the main hypothesis thattheir use of dissociation facilitates their performanceon simultaneous tasks and reduces task interference.There were fewer clear-cut signs of a weakening of the

executive-supervisory system, since on direct measuressuch as the Wisconsin Card Sorting Test, the patientsshowed no decline. However, on certain tasks that re-quire the supervisory function of allocating attentionalresources in response to task demands, such as theContinuous Performance Test, they did show impair-ment. The ability to cope with divided and selective at-tention tasks needs to be further studied.

The cognitive profile of the depersonalized group inthis study differs from reports on patients with disso-ciative identity disorder. Depersonalized subjectsscores were equivalent to those of comparison subjectson the intelligence test, whereas some case reports sug-gest that patients with dissociative identity disordershow above-average intelligence profiles (27), andmore recent studies demonstrate that dissociative iden-tity disorder is associated with cognitive inefficiencyand intertest scatter on intelligence tests (9). Both pa-tients with dissociative identity disorder and thosewith dissociative disorder not otherwise specified werereported to manifest abnormal intertest scatter on theverbal subtests of the WAIS-R (10). This was attrib-uted to deficits on the distractibility factor (arithmeticand digit span), which led the authors to recommendevaluating this population for comorbid attention def-icit disorder by using the Continuous PerformanceTest. Depersonalized subjects did not show more ver-bal scatter or deficits on the distractibility factor of theWAIS-R. They did demonstrate significant deficits onthe Continuous Performance Test; however, these sub-jects differ from typical patients with attention deficitdisorder (28) in that they have no particular difficultiessustaining attention over time, no increase in commis-sion errors, and no problems on the Stroop-ColorWord Test. The Continuous Performance Tests profileof the subjects with depersonalization disorder was ac-tually similar to reports on the functioning of patientswith schizophrenia spectrum disorders. A low percep-tual sensitivity on Continuous Performance Test items

with degraded stimuli was demonstrated with relativesof schizophrenic patients (29), replicated in later stud-ies with schizotypal subjects, and found to be indepen-dent of anxiety and depression measures (30). Lowperceptual sensitivity on the Continuous PerformanceTest was also shown to be associated with the type Bpersonality and with more frequent daydreams (31).

Limitations of this study include the small number ofsubjects in each group in addition to use of a widenumber of tests. The findings will need to be repli-cated. Future areas to focus on in studying depersonal-ization are primarily visual-spatial processing, atten-tion, and short-term memory. Visual, auditory, andsomatosensory modalities need to be studied in paral-lel and in intermodal integration. The logistic regres-sion analysis shows the feasibility of using such tests asthe Objective Diagnostic Criteria for Depersonaliza-tion. However, the fact that the same subjects wereused for the regression analysis limits the inferencesthat can be drawn from it, and it will need to be vali-dated on another group of subjects. To test the hypoth-

eses regarding the defensive functions of dissociation,it would be helpful to study whether deficits are con-tent dependent. Finally, it would be useful to study theconnection between neuropsychological deficits andthe depersonalized subjects sense of unreality. It stillneeds to be determined how their sense of unreality isrelated to disruptions in perception, an inability toconnect preexisting memory traces, affective tags (fa-miliarity), or to an altogether separate mechanism thatremoves from experiences their realness.

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