Mental and behavioural disorders due to psychoactive substance use (section F1): results of the ICD-10 field trial.

The ICD-10 field trial of section F1 (mental and behavioural disorders due to psychoactive substance use) shows comparatively high acceptance of the new classification in German-speaking countries. Goodness of fit and subjective confidence of the main diagnosis are above average. Analysis of interrater reliability with regard to main diagnostic categories reveal certain problems. The reliability values are flow average within the ICD-10 field study. Possible causes for low interrater reliability are inadequate differentiation from section F0 (organic disorders) and uncertainties in the differential assessment of psychopathological symptoms between F1 and F2, as also between F1 and F4. Interrater reliability could be improved by introducing "psychoactive substance use" as a separate axis in a forthcoming multiaxial scheme for ICD-10.