THE DISSOCIATIVE
EXPERIENCES
SCALE:
A Replication
Study
Colin A. Ross, M.D.,
G.R. Norton, Ph.D.,
and Geri Anderson, R.P.N.
Colin A. Ross, M.D., FRCP (C), is Associate Professor, De-
partment of Psychiatry, University of Manitoba. G.R. Nor-, i
ton, Ph.D., is Professor and Chairman, Department of Psy-
chology, University of Vinnipeg. Geri Anderson, R.P.N., is
Dissociative Disorders Nursing Research Assistant, Depart-
ment of Psychiatry, St. Boniface General Hospital, Win-
nipeg, Manitoba.
For reprints write: Colin A. Ross, M.D., FRCP (c), Depart-
ment of Psychiatry, St. Boniface General Hospital, 409 Tache
Avenue, Winnipeg, Manitoba, R2H 2A6, Canada.
ABSTRACT
The authors administered the Dissociative Experiences Scale to
medical student controls and patients with multiple personality
disorder, schizophrenia, panic disorder ,and chemical dependency.
Patients with MPD scored significantly higher than the other clinical
groups and the medical student controls.
Dissociative disorders are diagnosed according to formal
criteria in DSM-II1-R (American Psychiatric Association,
1987). Dissociative symptoms and experiences occur in both
clinical and nonclinical populations which do not have
diagnosable dissociative disorders. To date only two instru-
ments have been reported which reliably document the
dissociative experiences of clinical and nonclinical groups.
These are the Dissociative Experiences Scale (DES) (Bern-
stein and Putnam, 1986) and the Perceptual Alternation
Scale (PAS) (Sanders, 1986). The PAS has not been ade-
quately tested in clinical settings and consists of a subset of
MMPI questions.
The DES has good reliability and differentiates multiple
personality disorder from a variety of other clinical groups
and normal controls, an essential characteristic of any useful
screening instrument. It is a 28-item self-report inventory.
For the DES to be useful as a screening instrument for
dissociative experiences and disorders, replication of the
original findings in other centers is essential.
We have administered the DES to medical students and
patients with DSM-TIT-R diagnoses of panic disorder, alcohol
and/or anxiolytic abuse, schizophrenia, and multiple per-
sonality disorder (MPD).
METHOD
The DES was completed by 28 medical students, 13 panic
disorder patients, 24 chemical dependency patients, 20
schizophrenics and 17 patients with MPD. Subjects were the
first available members of each group who could be re-
cruited to complete the DES within the time limit. of the
study. All subjects met DSM-III-R criteria for their disorders.
The nature of the study was explained to the subjects and
verbal consent given. All information was given anony-
mously. Prior consent for the study of the prevalence of
dissociation in selected populations had been obtained
from the Faculty Committee on the Use of Human Subjects
in Research, Faculty of Medicine, University of Manitoba.
TABLE I
Dissociative Experiences Scale Scores in Selected Groups
Multiple
Personality
Disorder
Medical
Students
Panic
Disorder
Chemical
Dependency Schizophrenia
N=17 N=28 N=13 N=24 N=20
Median Score 40.7 4.9 3.9 10.3 12.6
(.00001) (.0004) (.0004) (.007)
 value denotes difference between that group and MPD
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DISSOCIATION, Vol.], No. 3: September 1988
The MPD subjects all received a longitudinal diagnosis
from the senior author. The panic disorder subjects were re-
cruited from an Anxiety Disorders Clinic with an active re-
search program ofwhich the senior author is Medical Direc-
tor. Chemical dependency subjects were drawn from a spe-
cialty clinicof the same department, and had been diagnos-
tically assessed by physicians specializing in the treatment of
chemical dependency. The schizophrenic subjects were re-
cruited from a long-term depot neuroleptic clinic in the
same department, and their charts were reviewed to ensure
that they had stable diagnoses of schizophrenia.
The score for each item and the overall score for each
subject were calculated using the method of Bernstein and
Putnam (1986). Statistical comparisons of the subitem and
overall scores between MPD and the other groups were
made using the Mann-Whitney U test.
RESULTS
As shown in Table 1, the median for the MPD group was
significantly higher than that for the other clinical groups or
the medical student controls. The Mann-Whitney U was
used because we were interested only in comparing each
group to MPD. Although non-parametric statistics were
used, mean scores are presented here to show that means
and medians do not differ very much for any group. Mean
scores for each group are: MPD 37.2 (S.D. 21.3); schizophre-
nia 17.1 (S.D. 15.3); chemical dependency 12.6 (S.D. 10.1);
panic disorder 8.6 (S.D. 9.9); medical students 5.6 (S.D. 4.8).
There were 7 (25.0%) items which differentiated MPD from
schizophrenia at the p < 0.05 level: these were items 6, 14, 15,
16, 21, 22 and 27.
All items except 19 differentiated MPD from medical stu-
dents; all but 1, 19, 24 and 28 differentiated MPD from panic
disorder; and all but 1, 4, 5, 8, 9, 19, 20, and 26 differentiated
MPD from chemical dependency at p < 0.05.
DISCUSSION
original series had slightly higher median scores than ours
(57.06), as did the schizophrenics (20.63). The alcoholics
(4.72) and agoraphobics (7.42) in Bernstein and Putnam
study were similar to our subjects, as were the normal
controls (4.38). We do not think that the slightly lower scores
of MPD and schizophrenic subjects in our study are concep-
tually significant. Such a degree ofvariation between centers
can be expected due to differences in patient populations.
We strongly recommend that any instruments developed
for the measurement of dissociative symptoms in the future
should be validated against the DES. For three reasons:
because the DES is valid and reliable; because it is the only
published instrument tested on clinical and control groups;
and because it has been replicated at another center.
The DES can be used to screen for the presence of disso-
ciative experiences in clinical and nonclinical populations.
Scores above 30 are almost. always associated with DSM-Ill-R
diagnoses of MPD or post-traumatic stress disorder in popu-
lations screened to date. Scores above 50 are rarely achieved
by persons without MPD. The DES can therefore be used as
a screening tool in clinical populations to identify patients
who require further assessment for dissociative disorders.
The ability of the DES to differentiate MPD from schizo-
phrenia on the item for auditory hallucinations, with MPD
scoring higher, is consistent with previous reports that Sch-
neiderian symptoms are common in MPD ( Kluft, 1987) . The
fact that only seven items on the DES differentiate MPD from
schizophrenia suggests that there is an extensive clinical
overlap between the two disorders and that a short form of
the DES might he useful. Many MPD patients are misdiag-
nosed as schizophrenic (Rosenbaum, 1980): use of the DES
might help to reduce false positive diagnoses of schizophre-
nia and false negative diagnoses of MPD.
In summary, the DES is a reliable and valid self-report
instrument for dissociative experiences. It has been shown
to be useful in differentiating MPD from other clinical
groups and controls in a center which did not participate in
the original development of the DES. 
These findings replicate those of Bernstein and Putnam
and further validate the DES. The MPD patients in the
REFERENCES
American Psychiatric Association. (1987). Diagnostic and statistical manual of mental disorders (3rd ed. Revised).Washington, DC:
Author.
Bernstein, E.M.,  Putnam, F.W. (1986). Development, reliability,and validityof a dissociation scale. Journal of Nervous and Mental
Disease, 174: 727-735.
Kluft, R.P. (1987). First-rank symptomsas a diagnostic clue to multiple personality disorder.American Journal of Psychiatry, 144,
293-298.
Rosenbaum, M. (1980).The role of theterm schizophrenia in the declineof diagnoses of multiple personality. Archives of General
Psychiatry, 37, 1383-1385.
Sanders, S. (1986). The perceptual alteration scale:a scale measuring dissociation.American Journal of Clinical Hypnosis, 29, 727-
735.
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DISSOCLATION, Vol.No. 3:September 1988