THE CLASSIFICATION of personality disorders is one of the most difficult challenges in the field of psychiatry. A fundamental question is whether they are best classified dimensionally or categorically and, more specifically, whether they are qualitatively distinct from normal personality traits.1,2 The study by Livesley et al1 is among the most informative and sophisticated efforts to empirically address this issue, and provides a tough standard against which future research in personality disorders will be measured (whether it is categorical or dimensional in nature).
Widiger TA. Four out of Five Ain't Bad. Arch Gen Psychiatry. 1998;55(10):865-866. doi:10.1001/archpsyc.55.10.865