The
Frequency of Multiple Among Psychiatric
Personality Inpatients
Cohn
Geri Anderson,
A. Ross,
William
Objective: disorder 23-bed
P. Fleisher,
A 2-year
were
Experiences
excluded.
was undertaken
Scale.
with
of multiple
personality
F.R.C.P.(C),
Individuals
scoring
to determine
the Dissociative
with
Disorders
disorder
prior
the frequency
diagnoses
20 or higher
and
subjects
were
multiple
cepted, agnosis
multiple ofmany
personality personality psychiatric
J Psychiatry
(Am
disorder. disorder patients.
1991;
will
Conclusions: become
here has been renewed interest in the dissociative disorders, especially multiple personality disorder, since 1 980 (1-4). Several reports have suggested that multiple personality disorder is much more common on psychiatric inpatient units than was previously suspected. Putnam and associates (5) diagnosed three cases of multiple personality disorder in about 225 psychiatnc inpatients, and Bliss and Jeppsen (6) made the diagnosis in 16% of SO inpatients. Ross (7) diagnosed mubtiple personality disorder in 4.4% of 68 inpatients admitted to a general adult inpatient unit over a year.
and
co-workers
multiple personality other dissociative adult inpatients.
These plc
(8) found
aside
quency
of multiple
the
cases
(3.3%)
patients of 60
of
with general
adult
reports
study
of the frequency
among
psychiatric
by Bliss
personality
interviewed
disorder
Scale
with
by a clinician
Ten subjects results
(3.3%) are
consideration
were
a diagnosis who
the Dissociative
Expe-
had clinically
replicated
and
ac-
in the differential
psychiatric
and
of multi-
di-
nonc!inical nity
ens (10),
health
to
date
ranges
have reported multiple personality disorders in a variety ofcliical and
populations
mental
in reports
including patients at a commu(9), prostitutes and exotic dancsurvivors (1 1 ), chemical dependency
center
sexualabuse
patients (12), and the general population (13). Loewenstein (14) has reviewed the literature on psychogenic amnesia and psychogenic fugue, noting the frequent occurrencc
of these
disorders
among
combat
troops.
To our knowledge, the present study is the first systematic screening of a large group of psychiatric inpatients
for
multiple
and reliable
personality
disorder
structured
interview
through
and blind
use
of
clini-
cab assessments.
inpatients.
Jeppsen,
disorder
inpatients
from 1% to 5%. Screening studies and other dissociative
a valid
disorder
Setting
two
disorder and 10 disorders in a group
arc the only
personality
subjects
to two the Dis-
148:1717-1720)
I
Saxe
a serious
personality
completed
If these
personality
Experiences
Then
was blind to all research data. Results: A total of299 subjects riences Scale and 80 received a structured diagnostic interview. confirmed
ofmultiple
of multiple
Schedule.
Ph.D.
individuals admitted were screened with
on the Dissociative
Interview
comparison
R.P.N.,
and G. Ron Norton,
adult psychiatric inpatients. Method: All in a teaching hospital in Winnipeg, Man.,
All subjects
interviewed
F.R.C.P.(C),
M.D.,
study
among general acute care wards
sociative
M.D.,
Disorder
among
the fregeneral
METhOD
Subjects Presented at the Seventh Annual International Conference on Multiple Personality/Dissociative States, Chicago, Nov. 9, 1990. Received Jan. 25, 1991; revision received May 15, 1991; accepted June 14, I 991 From the Department of Psychiatry, University of Manitoba, the Department of Psychiatry, St. Boniface Hospital, and the Department of Psychology, University of Winnipeg, Winnipeg, Man. Dr. Ross’s address is Charter Hospital Dallas, 6800 Preston Rd., Plano,
.
TX
75024.
Supported Foundation Copyright
Am
J
Reprints
of this
article
are
not
available.
by grants from the Manitoba Mental Health and the Manitoba Health Research Council. © 1991 American Psychiatric Association.
Psychiatry
148:12,
December
1991
Research
Subjects for the study were all individuals admitted to two 23-bed genera! adult psychiatric inpatient units at a university teaching hospital in Winnipeg, Man., over a 2-year period from July 1 8, 1 988, to July 1 7, 1990. Patients with a diagnosis of multiple personality disorden made before admission were excluded. A!! individuabs admitted during this period were approached and asked to participate in the study. Al! those agreeing to participate gave written consent; permission to ap-
1717
MULTIPLE
PERSONALITY
DISORDER
multiple proach the subjects had been obtained from the psychiatnists admitting patients to the units. The 20 companison subjects were drawn from the same patient population. Ethical approval for the project was meceivcd from the university’s faculty committee on the use of human subjects in research.
Procedure The study was conducted in three phases. In the first phase, a!! subjects were approached and asked to compbete the Dissociative Experiences Scale (15). The Dissociative Experiences Scale is a 28-item self-report measure that takes 5-1 0 minutes to complete. It yields an overall score ranging from 0 to 1 00; scores above 20
suggest the presence of posttraumatic stress disorder or a dissociative disorder. The Dissociative Experiences Scale has a test-retest reliability of 0.84 and good split half reliability (15). Group median discriminate subjects with multiple from other diagnostic groups and subjects (15, 16). General population are available (17, 18).
In the
second
phase
of the
scores on the scale personality disorder norma! comparison
norms
study
Schedule
is a structured
a!! subjects
who
interview
that
makes
DSM-III-R diagnoses of somatization disorder, major depressive episode, borderline personality disorder, and all the dissociative disorders (2, 19, 20). The schedule has an overall interraten reliability of 0.68 and good va-
lidity for the diagnosis of multiple personality disorder. In its original development the interview was administemed
to 80 subjects,
of whom
20 had
multiple
person-
abity disorder (21 ). Cohen’s kappa (22) for agreement between clinician and structured interview for the diagnosis of multiple personality disorder among these 80 subjects was 0.95. The schedule can discriminate subjects with multiple personality disorder from a number
of other
diagnostic
groups
(21, 23). The
Dissociative Disorders Interview in two sources (2, 20).
In the third
phase
of the study
full text
Schedule
a!! subjects
of the
is available
with
a di-
agnosis of multiple personality disorder according to the Dissociative Disorders Interview Schedule and companison subjects without a diagnosis of multiple personabity according to structured interview were given a clinical diagnostic interview by a clinician (W.P.F.) who
was blind to their clinical diagnoses and all research data. The clinician did not know the exact ratio of mu!tip!c personality to comparison subjects. The comparison subjects a!! scored 20 or higher on the Dissociative
Experiences
Scale
and
had completed
the structured
by gender
and age (within
10 years). Data
Analysis
The age, gender, length of stay, and discharge clinical diagnosis were tabulated for each individual admitted. Subjects who completed the Dissociative Experiences Scale were compared to those who did not complete the scale to determine whether the two groups differed on gender or age; two-tailed t tests were used for these analyses. The frequency of multiple personality disorder was calculated on the basis of the number of subjects who received a confirming c!inica! diagnosis from a clinician.
In addition,
the
total
number
ceived at least one dissociative Dissociative Disorders Interview
of subjects
who
me-
disorder diagnosis on the Schedule was calculated.
RESULTS
During the 2-year period of the study, 484 individua!s were admitted to the two wards, excluding patients previously diagnosed as having mu!tip!e personality disorder. Their mean age was 41.8 years (range=18-80 years), and 61.6% were women. The average length of stay was 37 days. The percentages of subjects with vanous discharge diagnoses were as follows: personality disorder, 31.0% (N=1SO); bipolar disorder, 23.8% (N=1 15); other mood disorders, 25.4% (N=123); psychotic disorder not elsewhere classified, 14.5% (N=70); schizophrenia, 14.3% (N=69); substance abuse, 9.1% (N=44); and organic mental disorder, 5.8% (N=28). Of the 484 subjects, 299 (61 .8 % completed the Dissociative Experiences Scale. Women made up 62. 1 % of those who completed the scale and 61.6% ofthose who
)
did
complete
the
nificant
not
(t=0.1,
df=481,
subjects
who
scale;
completed
n.s.). the
this
difference
The scale
was
mean±SD was
not
sig-
age of the
40.1±15.9
years,
compared who did
to a mean age of 44.6±17.8 years for those not complete the scale (t=2.9, df=476, p
Frequency of Multiple Among Psychiatric
Personality Inpatients
Cohn
Geri Anderson,
A. Ross,
William
Objective: disorder 23-bed
P. Fleisher,
A 2-year
were
Experiences
excluded.
was undertaken
Scale.
with
of multiple
personality
F.R.C.P.(C),
Individuals
scoring
to determine
the Dissociative
with
Disorders
disorder
prior
the frequency
diagnoses
20 or higher
and
subjects
were
multiple
cepted, agnosis
multiple ofmany
personality personality psychiatric
J Psychiatry
(Am
disorder. disorder patients.
1991;
will
Conclusions: become
here has been renewed interest in the dissociative disorders, especially multiple personality disorder, since 1 980 (1-4). Several reports have suggested that multiple personality disorder is much more common on psychiatric inpatient units than was previously suspected. Putnam and associates (5) diagnosed three cases of multiple personality disorder in about 225 psychiatnc inpatients, and Bliss and Jeppsen (6) made the diagnosis in 16% of SO inpatients. Ross (7) diagnosed mubtiple personality disorder in 4.4% of 68 inpatients admitted to a general adult inpatient unit over a year.
and
co-workers
multiple personality other dissociative adult inpatients.
These plc
(8) found
aside
quency
of multiple
the
cases
(3.3%)
patients of 60
of
with general
adult
reports
study
of the frequency
among
psychiatric
by Bliss
personality
interviewed
disorder
Scale
with
by a clinician
Ten subjects results
(3.3%) are
consideration
were
a diagnosis who
the Dissociative
Expe-
had clinically
replicated
and
ac-
in the differential
psychiatric
and
of multi-
di-
nonc!inical nity
ens (10),
health
to
date
ranges
have reported multiple personality disorders in a variety ofcliical and
populations
mental
in reports
including patients at a commu(9), prostitutes and exotic dancsurvivors (1 1 ), chemical dependency
center
sexualabuse
patients (12), and the general population (13). Loewenstein (14) has reviewed the literature on psychogenic amnesia and psychogenic fugue, noting the frequent occurrencc
of these
disorders
among
combat
troops.
To our knowledge, the present study is the first systematic screening of a large group of psychiatric inpatients
for
multiple
and reliable
personality
disorder
structured
interview
through
and blind
use
of
clini-
cab assessments.
inpatients.
Jeppsen,
disorder
inpatients
from 1% to 5%. Screening studies and other dissociative
a valid
disorder
Setting
two
disorder and 10 disorders in a group
arc the only
personality
subjects
to two the Dis-
148:1717-1720)
I
Saxe
a serious
personality
completed
If these
personality
Experiences
Then
was blind to all research data. Results: A total of299 subjects riences Scale and 80 received a structured diagnostic interview. confirmed
ofmultiple
of multiple
Schedule.
Ph.D.
individuals admitted were screened with
on the Dissociative
Interview
comparison
R.P.N.,
and G. Ron Norton,
adult psychiatric inpatients. Method: All in a teaching hospital in Winnipeg, Man.,
All subjects
interviewed
F.R.C.P.(C),
M.D.,
study
among general acute care wards
sociative
M.D.,
Disorder
among
the fregeneral
METhOD
Subjects Presented at the Seventh Annual International Conference on Multiple Personality/Dissociative States, Chicago, Nov. 9, 1990. Received Jan. 25, 1991; revision received May 15, 1991; accepted June 14, I 991 From the Department of Psychiatry, University of Manitoba, the Department of Psychiatry, St. Boniface Hospital, and the Department of Psychology, University of Winnipeg, Winnipeg, Man. Dr. Ross’s address is Charter Hospital Dallas, 6800 Preston Rd., Plano,
.
TX
75024.
Supported Foundation Copyright
Am
J
Reprints
of this
article
are
not
available.
by grants from the Manitoba Mental Health and the Manitoba Health Research Council. © 1991 American Psychiatric Association.
Psychiatry
148:12,
December
1991
Research
Subjects for the study were all individuals admitted to two 23-bed genera! adult psychiatric inpatient units at a university teaching hospital in Winnipeg, Man., over a 2-year period from July 1 8, 1 988, to July 1 7, 1990. Patients with a diagnosis of multiple personality disorden made before admission were excluded. A!! individuabs admitted during this period were approached and asked to participate in the study. Al! those agreeing to participate gave written consent; permission to ap-
1717
MULTIPLE
PERSONALITY
DISORDER
multiple proach the subjects had been obtained from the psychiatnists admitting patients to the units. The 20 companison subjects were drawn from the same patient population. Ethical approval for the project was meceivcd from the university’s faculty committee on the use of human subjects in research.
Procedure The study was conducted in three phases. In the first phase, a!! subjects were approached and asked to compbete the Dissociative Experiences Scale (15). The Dissociative Experiences Scale is a 28-item self-report measure that takes 5-1 0 minutes to complete. It yields an overall score ranging from 0 to 1 00; scores above 20
suggest the presence of posttraumatic stress disorder or a dissociative disorder. The Dissociative Experiences Scale has a test-retest reliability of 0.84 and good split half reliability (15). Group median discriminate subjects with multiple from other diagnostic groups and subjects (15, 16). General population are available (17, 18).
In the
second
phase
of the
scores on the scale personality disorder norma! comparison
norms
study
Schedule
is a structured
a!! subjects
who
interview
that
makes
DSM-III-R diagnoses of somatization disorder, major depressive episode, borderline personality disorder, and all the dissociative disorders (2, 19, 20). The schedule has an overall interraten reliability of 0.68 and good va-
lidity for the diagnosis of multiple personality disorder. In its original development the interview was administemed
to 80 subjects,
of whom
20 had
multiple
person-
abity disorder (21 ). Cohen’s kappa (22) for agreement between clinician and structured interview for the diagnosis of multiple personality disorder among these 80 subjects was 0.95. The schedule can discriminate subjects with multiple personality disorder from a number
of other
diagnostic
groups
(21, 23). The
Dissociative Disorders Interview in two sources (2, 20).
In the third
phase
of the study
full text
Schedule
a!! subjects
of the
is available
with
a di-
agnosis of multiple personality disorder according to the Dissociative Disorders Interview Schedule and companison subjects without a diagnosis of multiple personabity according to structured interview were given a clinical diagnostic interview by a clinician (W.P.F.) who
was blind to their clinical diagnoses and all research data. The clinician did not know the exact ratio of mu!tip!c personality to comparison subjects. The comparison subjects a!! scored 20 or higher on the Dissociative
Experiences
Scale
and
had completed
the structured
by gender
and age (within
10 years). Data
Analysis
The age, gender, length of stay, and discharge clinical diagnosis were tabulated for each individual admitted. Subjects who completed the Dissociative Experiences Scale were compared to those who did not complete the scale to determine whether the two groups differed on gender or age; two-tailed t tests were used for these analyses. The frequency of multiple personality disorder was calculated on the basis of the number of subjects who received a confirming c!inica! diagnosis from a clinician.
In addition,
the
total
number
ceived at least one dissociative Dissociative Disorders Interview
of subjects
who
me-
disorder diagnosis on the Schedule was calculated.
RESULTS
During the 2-year period of the study, 484 individua!s were admitted to the two wards, excluding patients previously diagnosed as having mu!tip!e personality disorder. Their mean age was 41.8 years (range=18-80 years), and 61.6% were women. The average length of stay was 37 days. The percentages of subjects with vanous discharge diagnoses were as follows: personality disorder, 31.0% (N=1SO); bipolar disorder, 23.8% (N=1 15); other mood disorders, 25.4% (N=123); psychotic disorder not elsewhere classified, 14.5% (N=70); schizophrenia, 14.3% (N=69); substance abuse, 9.1% (N=44); and organic mental disorder, 5.8% (N=28). Of the 484 subjects, 299 (61 .8 % completed the Dissociative Experiences Scale. Women made up 62. 1 % of those who completed the scale and 61.6% ofthose who
)
did
complete
the
nificant
not
(t=0.1,
df=481,
subjects
who
scale;
completed
n.s.). the
this
difference
The scale
was
mean±SD was
not
sig-
age of the
40.1±15.9
years,
compared who did
to a mean age of 44.6±17.8 years for those not complete the scale (t=2.9, df=476, p
