ICD vs. DSM
What is the difference between the ICD and DSM?
The ICD is a
core function of the World Health Organization, spelled out in its constitution
and ratified by all 193 WHO member countries. The ICD has existed for more than
a century, and became WHO's responsibility when it was founded in 1948 as an
agency of the United Nations. Before 1980, psychiatric diagnostic systems
reflected the dominant psychoanalytic ideas of the time, emphasizing the role
of experience, downplaying biology.
"The
American Psychiatric Association can really be credited with a revolution in
psychiatric nosology with the publication of DSM-III by introducing a
descriptive nosological system based on co-occurring clusters of
symptoms," said WHO psychologist Geoffrey Reed, PhD.
There was
very little international participation in the DSM-III, but at the time it may
have been impossible to make such a big shift at the international level, he
explained. As a result, DSM-III and ICD-8 (the version in effect at the time)
were quite different from one another but as the descriptive phenomenological
approach to diagnose mental disorders became dominant, the DSM and ICD have
become very similar, partly because of collaborative agreements between the two
organizations.
Still, there
is widespread sentiment that it is not helpful to the field to have two
separate classification systems for mental disorders. Many important
distinctions between the two systems remain, Reed said:
- The ICD is produced by a
global health agency with a constitutional public health mission, while
the DSM is produced by a single national professional association.
- WHO's primary focus for
the mental and behavioral disorders classification is to help countries to
reduce the disease burden of mental disorders. ICD's development is
global, multidisciplinary and multilingual; the primary constituency of
the DSM is U.S. psychiatrists.
- The ICD is approved by
the World Health Assembly, composed of the health ministers of all 193 WHO
member countries; the DSM is approved by the assembly of the American
Psychiatric Association, a group much like APA's Council of
Representatives.
- The ICD is distributed as
broadly as possible at a very low cost, with substantial discounts to
low-income countries, and available free on the Internet; the DSM
generates a very substantial portion of the American Psychiatric
Association's revenue, not only from sales of the book itself, but also
from related products and copyright permissions for books and scientific
articles.
Will the DSM
be superseded by the ICD? There is little justification for maintaining the DSM
as a separate diagnostic system from the ICD in the long run, particularly
given the U.S. government's substantial engagement with WHO in the area of
classification systems. But, said Reed, "there would still be a role for
the DSM, because it contains a lot of additional information that will never be
part of the ICD. In the future, it may be viewed as an important textbook of
psychiatric diagnosis rather than as the diagnostic 'Bible.'"
