SCREENING FOR MPD:
CLINICAL UTILITY OF
THE QUESTIONNAIRE
OF EXPERIENCES OF
DISSOCIATION
GaryE. Dunn, Ph.D.
Joseph J. Ryan, Ph.D.
Anthony M. Paolo, Ph.D.
Darrell M,S.W.
Gary E. Dunn, Ph.D., is Staff Psychologist at the Dwight D.
Eisenhower Veterans Administration Medical Center, in
Leavenworth, Kansas. Joseph J. Ryan, Ph.D., is Chief of the
Psychology Service at the Dwight D. Eisenhower Veterans
Administration Medical Center. Anthony M. Paolo, Ph.D.,
is Assistan t Professor of Neurology at the University of Kansas
Medical Center. Darrell Miller, M.S.W., is a Social Worker
at the Johnson County Mental Health Center in Kansas.
For reprints write: Gary E. Dunn, Ph.D., Psychology Service
(116B) DDE VAMC, Leavenworth, Kansas 66048.
ABSTRACT
The major purpose of this study was to determine the effectiveness
of the Questionnaire ofExperiences ofDissociation (QED) as a screen-
ing instrument for the diagnosis of multiple personality disorder
(MPD). The QED was administered to 18 patients with MPD, 18
control subjects, 18 alcoholics, and 15 patients diagnosed with both
PTSD and a substance abuse disorder. Using a cut-off score of 15,
the QED correctly identified all MPD patients as needing further
screening. None of the control subjects, and only one of the alco-
holics, were incorrectly identified as requiring further evaluation.
These preliminary findings suggest that the QED has good clinical
utility as a screening tool for the identification of individuals who
are afflicted with multiple personality disorder.
INTRODUCTION
There is a need to screen for dissociative disorders, includ-
ing multiple personality disorder, in psychiatric and sub-
stance abuse populations. (Dunn, 1992) . The Questionnaire
of Experiences ofDissociation (QED) (Riley, 1988) was devel-
oped as a brief assessment technique for the study of disso-
ciation. Riley reported that non-clinical populations aver-
aged 9.92 points on the scale compared to 24.6 points for
patients with multiple personality disorder (MPD) . However,
the clinical utility of these scores was questionable since only
three MPD patients were involved in the Riley study, and he
omitted standard deviation and range statistics from the
manuscript. Additionally, there was no information provid-
ed regarding a cut-off score which practitioners might use
to determine whether further evaluation of a dissociative
disorder was indicated.
The purpose of the present study was two-fold. First, we
investigated the utility of the QED as a screening tool for
multiple personality disorder. The second step involved the
determination of a cut-off score that may be used to indi-
cate the need for further assessment of a possible dissocia-
tive disorder.
METHOD
Subjects
Four groups of subjects were included in the present
study. Group I (MPD) consisted of 18 individuals diagnosed
as suffering multiple personality disorder. Of these, ten were
receiving outpatient therapy at a midwestern community men-
tal health center and eight were in therapy with a private
practitioner. Each was diagnosed according to DSM-III-Rcri-
teria. (American Psychiatric Association, 1987). Means and
standard deviations for age and education were 37.00 years
(SD=6.86) and 13.78 years (SD=2.64) , respectively. Fourteen
patients were female (77.8%) and four were male (22.2%).
Group II (control) consisted of 18 normal individuals
living in the local community who were matched with the
MPD patients on age, education, and gender. None had been
treated for a psychiatric disorder. Means and standard devi-
ations for age and education were 38.72 years (SD= 8.72) and
14.67 years (SD-2.09) respectively.
Group III (alcoholics) consisted of 18 males being treat-
ed for alcohol abuse, or alcohol dependence, on an inpa-
tient unit in a midwestern Department of Veteran Affairs
Medical Center. They were matched with the MPD and con-
trol subjects on age and education. The means and standard
deviations for age and education were 40.72 years (SD=4.64)
and 13.33 years (SD=2.00), respectively.
Group IV (PTSD) consisted of 15 patients, diagnosed,
with post-traumatic stress disorder by a staff psychiatrist, using
DSM-111R criteria. They were receiving inpatient treatment
for a substance abuse problem at a midwestern Department
of Veteran Affairs Medical Center. Fourteen were male (93.3%)
and one was female (6.7%). Means and standard deviations
for age and education were 43.40 years (SD=4.22) and 12.07
years (SD=1.87), respectively.
A oneway analysis of variance indicated a significant age
difference across the groups, F (3.65) - 2.98, p<.04. A Tukey
post-hoc analysis revealed that the PTSD group was signifi-
cantly older than the MPD group (43.40 vs 37.00, p, <.05).
No other age differences emerged. However, oneway anal-
ysis of variance revealed a significant difference in educa-
tion across groups, F (3.65) = 4.46, p,<.Ol. A Tukey post-
hoc analysis showed that the control subjects had significantly
more years of schooling than the PTSD/substance abuse group,
38
DISSOCIATION, Col, VI, Na 1. Mardi 1993
DUNN/RYAN/PAOLO/MILLER
TABLE 2
Sensitivity and Specificity Rates for Various
QED Cut-off scores (MPD vs PTSD)
(14.67 vs 12.07, p.<.05). No other differences were found.
Instrument
The Questionnaire of Experiences of Dissociation ( QED)
(Riley, 1988) consists of 26 true-false items which were drawn
from the clinical literature dealing with dissociative and mul-
tiple personality disorders. As noted previously, normals pro-
duced a mean score of 9.92 (SD=4.28) , while the mean score
for three MPD patients was 24.6 (Riley, 1988). No cut-off
scores have been developed to determine whether further
assessment is needed to rule out a dissociative disorder.
Procedure
Subjects in the alcohol and PTSD groups completed the
QED as part of the routine psychological evaluation done
on the substance abuse unit between April, 1991 and
November, 1992. The MPD subjects were in psychotherapy
with one of the authors (D.M.) and agreed to complete the
screening instrument for research purposes during the fall
of 1992. Control subjects, who lived in the same metropoli-
tan area as those with MPD, also agreed
to complete the QED for research pur-
poses during the fall of 1992. MPD and
control subjects completed a demo-
graphic sheet and signed a consent
form.
To make the QED a functional
instrument for the clinician, it was
important to establish a meaningful cut-
off score for determining whether fur-
ther assessment of a dissociative disorder
was warranted. Similarly to the method
employed by Steinberg, Rousaville and
Cichetti (1991) with the DES, the pre-
sent procedure was to maximize sen-
sitivity: the ability to correctly identify
true positive cases of dissociative dis-
orders, and maximize specificity; and
the ability to correctly identify persons
without a dissociative disorder. In this
way, false positive cases would be min-
imized and fewer cases of true disso-
ciative disorders would be missed. A
number of QED values were tested in
order to determine the most optimal
score.
RESULTS
Means and standard deviations on
the QED are presented in Table 1. A
oneway analysis of variance indicated
a significant difference across groups,
F (3.65) = 46.11, p_<.0005. A Tukey
post-hoc analysis demonstrated that
MPD subjects achieved a higher mean
score than the other groups, and that
the PTSD group achieved a higher
score than the alcohol or control groups
(p_<.05). No other significant differences were found.
Inspection of the score distributions of the four groups
revealed no overlap between the MPD and controls, and only
one person overlapped between the MPD and alcohol group
when using a cut-off score of> 15. Substantial overlap of the
distributions occurred between the MPD group and PTSD
groups. Therefore, the score of> 15 points maximized sen-
sitivity and specificity between the MPD group and the con-
trol and alcohol groups. Thus, it was decided that a score of
15 or greater was the optimal cut-off.
Using a cut-off score of > 15, the QED classified all 18
MPD subjects as needing further evaluation for a dissocia-
tive disorder. Each of the 18 control subjects were classified
as not being in need of further evaluation. Seventeen of 18
alcoholics (94.4%) and 9 of 15 PTSD subjects (60%) achieved
QED scores which indicated that further evaluation was not
warranted.
Contrasting MPD and controls, a cut-off of 15 correctly
classified all subjects resulting in 100% sensitivity and speci-
TABLE 1
Means, Standard Deviations, and Ranges of QED scores
by Diagnostic Group
Mean SD Range
MPD 21.06 3.56 15.00 - 26.00
Control 6.33 2.74 2.00 - 11.00
Alcoholic 6.33 3.68 0.00 - 15.00
PTSD 13.33 4.30 6.00 - 22.00
Cut Off Score Sensitivity Specificity
15 100% 60.0%
16 94.4% 66.7%
17 83.3% 73.3%
18 83.3% 86.7%
19 66.7% 86.7%
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DISSOCIATION. Vol. VI, March199 3
SCREENING FOR MPD
ficity. For MPD versus alcoholics, 100% sensitivity and 94.4%
specificity was achieved. Using 15 as a cut-off score, a com-
parison of the MPD and PTSD subjects resulted in 100% sen-
sitivity and 60% specificity. Table 2 presents sensitivity and
specificity results for additional QED cut-off scores in com-
paring the MPD and PTSD groups. Contrasting the MPD sub-
jects with all non-MPD subjects combined, a cut-off score of
15 resulted in 100% sensitivity and 86.3% specificity, with
an overall hit rate of 89.8%.
DISCUSSION
The present study indicates that the QED has potential
as a screening device for MPD, given its ease of administra-
tion, response format, and brevity. Using a cut-off score of
15, all MPD subjects were classified as needing a more for-
mal diagnostic evaluation for the presence of a dissociative
disorder. To further support its effectiveness, the QED was
able to correctly classify 100% of control subjects and over
94% of alcoholics as not being in need of additional evalu-
ation. When the entire sample is dichotomized into MPD
versus non-MPD subjects, the overall hit rate for the QED is
approximately ninety percent.
In regard to the PTSD group, the QED indicated that
40% of the subjects required further evaluation. This find-
ing is not problematic, however, and may actually strength-
en the credibility of the QED as a screening instrument for
dissociative disorders. Previous research found significant
dissociative experiences among patients diagnosed with PTSD
(Bernstein & Putnam, 1986; Branscomb, 1991; Bremner et
al, 1992). Furthermore, there is some evidence to support
re-classifying PTSD as a dissociative disorder (Davidson &
Foa, 1991).
Several limitations should be noted regarding the pre-
sent study. First, demographic variables were not equivalent
across all groups. The PTSD group was approximately six
years older, on average, in comparison to the MPD group.
They also averaged about two and a half years less educa-
tion in comparison to the control group. Finally, gender was
not equivalent across the groups. While the MPD and con-tr
ol groups each included 14 females and four males, the
alcoholic group was entirely male and the PTSD abuse group
had only one female. It is possible that these demographic
differences skewed the overall results. For example, the preva-
lence rate of multiple personality disorder is considered, by
some experts, to be at least five times higher in females than
males (Putnam, 1989). Thus, lower QED scores among the
alcoholics and PTSD subjects may be a reflection, in part, of
the gender distribution of the samples. However, other noted
authorities have hypothesized that the actual male to female
ratio of MPD in the general population is actually closer to
one to one (Ross, 1989). Along the same lines, age dispari-
ties in the groups may have contributed to QED differences
given that dissociative experiences have been found to decline
with age (Ross, Joshi, & Currie 1990). A second limitation
is that the PTSD group was not pure. It consisted of indi-
viduals who were being treated for some type of substance
abuse and had a history of PTSD. It is unclear as to what the
outcome would have been if individuals with a primary diag-
nosis of PTSD would have been included.
Another limitation is the inflated sensitivity and speci-
ficity values due to a base rate of approximately 50% for the
majority of analyses. Although an adequate hit rate was demon-
strated when all groups were combined (base rate of 26%),
the utility of the QED would certainly be reduced as base
rates become lower. However, one study revealed a base rate
of 39% for dissociative disorders in a substance abuse pop-
ulation (Ross, et al., 1992), suggesting that a base rate of
26% may not be too unusual for some populations.
Nevertheless, it would be beneficial to attempt to repli-
cate these findings in a population where base rate of dis-
sociative disorders, as well as other psychiatric syndromes,
more closely approximate those found in other treatment
settings. Finally, further research is needed using the QED
with a more balanced sample of males and females within
various diagnostic groups.
CONCLUSION
Despite the noted limitations, results of the present study
indicate that the QED may be used as a screening tool for
multiple personality disorder. Using a score of 15 as a cut-
off, it was able to effectively distinguish patients with MPD
from normals and alcoholics. If one considers PTSD as a pos-
sible dissociative disorder the current findings support the
use of the QED to screen for dissociative disorders. Further
research is needed to replicate these findings as well as to
test the QED with other diagnostic groups.
Additionally, future studies are needed to determine if
different QED norms exist based on geographic location,
ethnicity, socio-economic status. etc. Finally, comparative
studies, using the DES and QED may prove important in
terms of their relative effectiveness as a screening instru-
ment with various diagnostic groups. 
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