Important questions remain to be addressed before adopting a dimensional classification of mental disorders.

Comments on the original article "Plate tectonics in the classification of personality disorder: Shifting to a dimensional model," by T. A. Widiger and T. J. Trull. Widiger and Trull raised important nosological issues that warrant serious consideration not only for the personality disorders but for all mental disorders as the Diagnostic and Statistical Manual of Mental Disorders (DSM) is revised during the next few years. As argued compellingly by these authors, dimensional classification may indeed offer substantial improvement over the present categorical system. Several questions remain to be addressed in evaluating whether this is the case and, if so, how dimensional classification can be implemented to best serve the disparate users of the DSM.