A global field study of the international classification of diseases (ICD-11) mood disorders clinical descriptions and diagnostic guidelines.

Background: We report results of an internet-based field study evaluating the diagnostic guidelines for ICD-11 mood disorders. Accuracy of clinicians' diagnostic judgments applying draft ICD-11 as compared to the ICD-10 guidelines to standardized case vignettes was assessed as well as perceived clinical utility.

Methods: 1357 clinician members of the World Health Organization's Global Clinical Practice Network completed the study in English, Spanish, Japanese or Russian. Participants were randomly assigned to apply ICD-11 or ICD-10 guidelines to one of eleven pairs of case vignettes.

Results: Clinicians using the ICD-11 and ICD-10 guidelines achieved similar levels of accuracy in diagnosing mood disorders depicted in vignettes. Those using the ICD-11 were more accurate in identifying depressive episode in recurrent depressive disorder. There were no statistically significant differences detected across classifications in the accuracy of identifying dysthymic or cyclothymic disorder. Circumscribed problems with the proposed ICD-11 guidelines were identified including difficulties differentiating bipolar type I from bipolar type II disorder and applying revised severity ratings to depressive episodes. Clinical utility of ICD-11 bipolar disorders was found to be significantly lower than for ICD-10 equivalent categories. Limitations: Standardized case vignettes were manipulated to evaluate specific changes. The degree of accuracy of clinicians' diagnostic judgments may not reflect clinical decision-making with patients.

Conclusions: Alignment of the ICD-11 with current research appears to have been achieved without sacrificing diagnostic accuracy or clinical utility though specific training may be necessary as ICD-11 is implemented worldwide. Areas in which the ICD-11 guidelines did not perform as intended resulted in further revisions.