New data toward fulfilling the promise of the ICD-11 severity criterion.

Great progress has been made in furthering our understanding of the long-term course of personality pathology. However, our knowledge about the long-term outcomes of personality disorder, thus far, is based on a polythetic and categorical definition of personality disorder. This special issue brings together a set of papers reporting on the results of the 30-year prospective study, the Nottingham Study of Neurotic Disorder, in addition to presenting a study protocol for a future study, the Boston (UK) Personality Project, and results from a study of lived experience of individuals who have been in treatment for personality challenges. Together, these papers highlight the value in viewing personality pathology not as a categorically defined disorder, but as a severity criterion related to functioning. This special issue paves the way for considering how to further refine and conceptualize the general severity criterion common to all manifestations (types) of personality disorder.