The DSM stands for the
Diagnostic and Statistical
Manual of mental disorders
and only focuses on
diagnosis of mental health
disorders.
The DSM is only in English
and is limited to certain
countries - inaccessible to
the whole world.
Its diagnoses are based
one symptoms as well as
existing medical issues
and environmental
stressors.
The DSM is revised
regularly and is
currently on its fifth
edition.
The mental health disorders
are put on 5 axes, which
include psychiatric diagnoses,
personality problems, general
medical conditions,
environmental stress and
'global functioning'.
ICD-10
The ICD stands for the
International Classification of
Disorders. It focuses on all
health conditions, including
mental health.
The ICD is
multi-lingual and aims
to improve healthcare
and diagnosis all over
the world.
The ICD is in its 10
edition and is
reviewed regularly.
Its diagnoses
are based on
symptoms only.
Section F of the ICD is specific for mental
health disorders and within this section,
each disorder is grouped in a family. For
example, depression is part of the the mood
disorders (represented by the family digit 3).
More digits can be added to this to represent
the specific disorder, the sub-type of the
disorder, and very specific categorisations.
Reliability
Reliability refers to
whether diagnosis is
consistent regardless
of clinician.
One issue with reliability of diagnosis
is the subjectivity of criteria. This is
because one clinician may believe a
behaviour meets a certain criteria
whereas another may not.
Inter-rater reliability is when
two or more clinicians use
the same diagnostic tool and
come to the same diagnosis
for the same individual.
Rosenhan found that the DSM-II had high
inter-rater reliability as 7/8 pseudo patients
in the study (with the same symptoms) were
all diagnosed with schizophrenia by
different clinicians using the DSM-II.
Goldstein found that the DSM-III
also had high inter-rater reliability,
and Brown found the DSM-IV had
high inter-rater reliability.
Test-retest reliability is
when the same diagnosis is
reached with the same
diagnostic tool but after a
period of time to see if the
diagnosis is consistent.
Pontinovsky found the
ICD had good test
re-test reliability.
Sanchez-Villegas found the
DSM-IV-TR also has high
test re-test reliability.
Validity
Validity refers to if the
diagnosis is correct,
reflects the actual disorder
and can lead to a suitable
treatment that works.
Validity can be affected by many factors, such
as comorbidity (when symptoms overlap and
can be applied to multiple disorders) which
leads to a higher chance of misdiagnosis,
implicit bias of the clinician (when a clinician's
prejudices against people may influence their
diagnosis), patient factors like accent which
could lead to a misinterpretation of
information, and revisions of systems which
can improve the validity of diagnostic systems.
Construct validity refers
to how far the constructs
that are being measured
represents that disorder.
Brown et al found that the
DSM-IV had low construct
validity.
However, Stinchfield
found that the DSM-IV had
high construct validity.
Concurrent validity is when two
tests done at the same time come
up with the same diagnosis, which
would suggest the tests measure
what they seem to measure.
Hoffman and Lee found that DSM
criteria had high concurrent validity
with other diagnostic tools such as
interviews and questionnaires.