BACKGROUND: The Clinical descriptions and diagnostic guidelines for the ICD-11 Classification of mental and behavioural disorders should soon be finalized. To measure their potential impact, the new proposed definitions of bipolar disorders in ICD-11 were applied to data from the Zurich cohort study and compared with the definitions of ICD-10 and DSM-5.
RESULTS: We found little difference between ICD-11 and ICD-10 in the identification of subjects with bipolar disorders, but compared to DSM-5 a considerable increase in the diagnosis of hypomanic episodes and therefore of bipolar-II disorders.
CONCLUSIONS: Compared to ICD-10 and DSM-5 the definition of hypomanic episodes according to ICD-11 represents important progress. A higher prevalence of BP-II disorder makes sense from a clinical point of view. Further transcultural research is needed into whether out-patient treatment should be included as a criterion for hypomania. Pure mania is unfortunately missing as an independent and codable disorder in the international diagnostic manuals, whether ICD-11 or DSM-5.