from theDSMsystem was made. The demise of
homosexuality as a disease entity occurred through
a vote of the psychiatric membership.
This example also serves as a reminder that classi-
fication systems such as theDSMare crafted by com-
mittees. The members of such committees represent
varying scientific, theoretical, professional, and even
economic constituencies. Consequently, the final
classification product adopted may represent a poli-
tical document that reflects compromises that will
make it acceptable to a heterogeneous professional
clientele.
Description. Without doubt, the DSM-IV-TR
provides thorough descriptions of the diagnostic
categories. For Axis I and II disorders, a detailed
description of the symptoms of each diagnostic cate-
gory is presented. As an example, Table 5-5 presents
theDSM-IV-TRdiagnostic criteria for the eating
disorder bulimia nervosa. TheDSMprovides addi-
tional information for each diagnosis, including the
age of onset, course, prevalence, complications,
family patterns, cultural considerations, associated
descriptive features and mental disorders, and associ-
ated laboratory findings. All this descriptive detail
should enhance the system’s reliability and validity.
Reliability. A system of classification that cannot
establish its reliability has serious problems. In this
context,reliabilityrefers to the consistency of diag-
nostic judgments across raters. One of the major
changes inDSM-III(American Psychiatric Associa-
tion, 1980)—the inclusion of specific and objective
criteria for each disorder—reflected an attempt to
increase the reliability of the diagnostic system. If
Psychologist A and Psychologist B both observe
the same patient but cannot agree on the diagnosis,
then both their diagnoses are useless because we do
not know which to accept. This is the very situa-
tion that plagued the American diagnostic systems
for many years. For example, an early study illus-
trating the unreliability of previous diagnostic sys-
tems was carried out by Beck, Ward, Mendelson,
Mock, and Erbaugh (1962). Two different psychia-
trists each interviewed the same 153 newly admit-
ted psychiatric patients. Overall agreement among
these psychiatrists was only 54%. Some of the dis-
agreements in diagnosis seemed to stem from
inconsistencies in the information patients pre-
sented to the psychiatrists. For example, Patient A
may have been relatively open with Psychiatrist F,
but less so with Psychiatrist G. However, much of
the unreliability problem seemed to lie with the
diagnosticians and/or the diagnostic system itself.
Certain pragmatic factors can also reduce reliabil-
ity across diagnosticians. Sometimes a given institution
will not admit patients who carry a certain diagnosis.T A B L E 5-5 DSM-IVCriteria for Bulimia
Nervosa
A. Recurrent episodes of binge eating. An episode of
binge eating is characterized by both of the
following:
(1) eating, in a discrete period of time (e.g., within
any 2-hour period), an amount of food that is
definitely larger than most people would eat
during a similar period of time and under similar
circumstances
(2) a sense of lack of control of eating during the
episode (e.g., a feeling that one cannot stop eat-
ing or control what or how much one is eating)
B. Recurrent inappropriate compensatory behavior in
order to prevent weight gain, such as self-induced
vomiting; misuse of laxatives, diuretics, enemas, or
other medications; fasting; or excessive exercise.
C. The binge eating and inappropriate compensatory
behaviors both occur, on average, at least twice a
week for 3 months.
D. Self-evaluation is unduly influenced by body shape
and weight.
E. The disturbance does not occur exclusively during
episodes of Anorexia Nervosa.
Specify Type
Purging Type: During the current episode of Bulimia
Nervosa, the person has regularly engaged in self-
induced vomiting or the misuse of laxatives, diuretics, or
enemas.
Nonpurging Type: During the current episode of Bulimia
Nervosa, the person has used other inappropriate com-
pensatory behaviors, such as fasting or excessive exercise,
but has not regularly engaged in self-induced vomiting or
the misuse of laxatives, diuretics, or enemas.
Reprinted with permission from theDiagnostic and Statistical Manual of
Mental Disorders, Fourth Edition, Text Revision,Copyright © 2000 American
Psychiatric Association.DIAGNOSIS AND CLASSIFICATION OF PSYCHOLOGICAL PROBLEMS 149