IPDE - Extranet Systems - World Health Organization

89 Discussion and Conclusions
emotionally unstable, ICD-10 requires four of seven criteria for a diagnosis;
and except for antisocial, DSM-III-R requires four or five from a
list that varies from seven to nine criteria. Although there are fewer differences
between ICD-10 and DSM-IV, many still remain.
A more detailed comparison of ICD-10, DSM-III-R, and DSM-lV is
beyond the scope of this chapter. However, mention should be made of
the extent to which ICD-10 and DSM-III-R tended to produce similar
results in the present study. Within the limitations imposed by the sample
sizes of the individual disorders, no statistically significant (pc.05)
differences were observed in the base rates with which the corresponding
specific PDs were diagnosed in the overall sample of 716 patients.
There was a trend, albeit statistically not significant, for DSM-III-R to
identify more cases of antisocial, paranoid, and histrionic behaviour and
for ICD-I0 to diagnose more cases of anxioudavoidant behaviour. Both
systems provide a residual category for cases judged to have a PD that
does not meet the requirements for any of the specific types. There is no
method of identifying these patients without invoking some arbitrary
standard. The IPDE assigns a residual diagnosis to anyone who does not
meet the requirements for a specific disorder, but nevertheless accumulates
10 or more criteria €mm the various disorders. There are more
opportunities to obtain the diagnosis in DSM-III-R than in ICD-10
because the former has l l0 criteria and the latter only 56. It is not surprising,
then, that approximately twice as many patients received a nonspecific
diagnosis of PD in DSM-III-R as in ICD-I0 (12.8% vs 6.8%).
This, of course, does not address the question of whether the two classification
systems actually identified the same patients as having a particular
disorder. That can be determined by the kappa statistic, particularly
for those disorders with a prevalence of at least 5%. There are only two
of them; the kappas are 0.66 (borderline) and 0.52 (anxiouslavoidant),
evidence of moderate but far €mm perfect agreement. With the distribution
of cases in the sample of 716 patients, these kappas were associated
with 92% agreement regarding the diagnosis of borderline and 89% for
anxioudavoidant. The kappa values for the remaining disorders should
be viewed as relatively unstable because of the base rate problem. They
range from 0.32 (dissocial) to 0.61 (anankastidobsessive-compulsive),
with a median of 0.52. The DSM-III-R and ICD-10 comparisons should
not be a f f d by the less-than-perfect interrater reliability of the IPDE
since the same examiner conducted the interview and rated the information
on which the ICD-l0 and DSM-111-R diagnoses for a padcular
patient were based.