Organic, including symptomatic, mental disorders (section F0)--results of the ICD-10 field trial.

The natural history of classification systems for the organic mental disorders from ICD-8 through ICD-10 and DSM-III is presented. Out of a total of 31 cases the 6 with a main diagnosis of the F0-section of ICD-10 are described and field trial results analysed in terms of classification errors, goodness of fit, difficulty, and interrater-reliability. Specific categories (instead of "collective categories") were used more frequently and fewer classification errors made on the basis of ICD-10 as compared with ICD-9. The authors suggest that an operationalized differentiation of dementia as one of the core categories would further increase the reliability and clinical practicability of this section.