Psychiatric Diagnosis and Classification - ResearchGate

28 PSYCHIATRIC DIAGNOSIS AND CLASSIFICATION
separate section on mental disorders. Since then extensive efforts have been
undertaken to better define the mental disorders. There has been a synchronybetween
ICD-6 and DSM-I, ICD-8 and DSM-II, ICD-9 and DSM-III
and ICD-10 and DSM-IV with increasing harmonyand consistencythanks
to the international collaboration.
In the most recent tenth revision of the ICD ICD-10), the mental disorders
chapter has been considerablyexpanded and several different descriptions
are available for the diagnostic categories: the ``clinical description and
diagnostic guidelines'' CDDG) [1], a set of ``diagnostic criteria for research''
DCR) [2], ``diagnostic and management guidelines for mental disorders in
primarycare'' PC) [13], ``a pocket guide'' [14], a multiaxial version [15] and
a lexicon [16]. These interrelated components all share a common foundation
of ICD grouping and definitions, yet differentiate to serve the needs of
different users.
In the ICD-10, explicit diagnostic criteria and rule-based classification have
replaced the art of diagnosis with a reliable and replicable system that has
considerable predictive validityin terms of effective interventions. Its development
has relied on international consultation and has been linked to the
development of assessment instruments. The mental disorders chapter of the
ICD-10 has undergone extensive testing in two phases to evaluate the CDDG
as well as the DCR. The field trials of the CDDG [17] were carried out in 35
countries where joint assessments were made of 2460 different patients. For
each patient, clinicians who were familiarized with the CDDG were asked to
record one main diagnosis and up to two subsidiarydiagnoses. Inter-rater
agreements, as measured bythe kappa statistic, for most categories in the
``two-character groups'' e.g. F2, schizophrenic disorders) were over 0.74,
indicating excellent agreement. It was lowest at 0.51 for the F6 category,
which includes personalitydisorders, disorders of sexual preference, disorders
of gender identityand habit and impulse disorders. At a more
detailed level of diagnosis, agreement on individual personalitydisorders
except dyssocial personality disorder), mixed anxiety and depression states,
somatization disorder and organic depressive disorder were below acceptable
limits. As a result, the descriptions for these categories were improved
and clarified. Some categories were omitted altogether from the ICD-10 due
to poor reliabilitye.g. the categoryof hazardous use of alcohol).
Based on the experience gathered from the field trials of the CDDG, the
ICD-10 DCR were developed with the assistance of experts from across the
world. Operational criteria with inclusion and exclusion rules were specified
for each diagnostic category. For the DCR field trials [18], 3493 patients were
assessed in a clinical interview bytwo or more clinicians across 32 countries.
Once again, for the F6 categorythe kappa value of 0.65 though improved
from the CDDG field trials) was lower than for the other 9 two character
categories, which all had kappas over 0.75. For the more detailed diagnoses,