What is "functional impairment"? Disentangling disability from clinical significance

The formulation of disability (or "functional impairment") is currently not operationalized in either the ICD or the DSM. In the DSM system, making a diagnosis depends on a conjoint assessment of symptoms and functioning, whereas the ICD keeps the disability construct separate from the diagnosis of mental disorders. We need an internationally agreed conceptualization between ICD and DSM in terms of better operationalization of disease and disability components. No functioning or disability should appear as part of the threshold of the diagnosis in either system.