Diagnosing dementia -- ICD-10 not so bad after all: a comparison between dementia criteria according to DSM-IV and ICD-10.

BACKGROUND

The discrepancy between results of diagnosing dementia with ICD-10 and DSM-IV has been shown by several studies. Our aim was to show that the two diagnostic systems are more or less alike if ICD-10 is interpreted in the way we believe is in the intention of the ICD-10 authors.

METHODS

Two hundred and seven patients consecutively referred patients and their caregivers were interviewed and the patients were clinically examined. Algorithms using criteria for the World health Organization's International classification of Diseases, 10(th) revision (ICD-10) and the American Psychiatric Association's, the fourth edition (DSM-IV) were followed to diagnose dementia.

RESULTS

A diagnosis of dementia was made for 198 patients and there was 100% agreement (kappa = 1,0) between ICD-10 and DSM-IV diagnosis.

CONCLUSION

In the ICD-10 criteria 'decline in other cognitive abilities such as abstraction, judgement, problem solving' has been interpreted in a way that all the above executive functions must be impaired for diagnosing dementia. According to our interpretation these are meant to be examples of functions which may be compromised in demented patients.The results of our study demonstrate that this interpretation of ICD-10 has shown that the authors of ICD-10 and DSM-IV have succeeded in harmonising the two systems. However, the ICD-10 criteria are phrased in a way that leaves much to individual interpretation. WHO has to define the ICD criteria in such a way that there is uniformity in its interpretation.