ABSTRACT
Do personality disorders exist? What distinguishes normal and abnormal personality variation? Are normal and abnormal personality qualitatively different, or merely quantitatively? How many personality disorders are there, and how can you tell? Such questions concern the construct validity of personality disorders. In examining the construct validity of personality disorders, there are at least three levels to consider (Clark, Livesley, & Morey, 1997): (a) the conceptualization of the constructs themselves, (b) the formulation of the constituent (DSM) diagnostic criteria sets, and (c) the instruments used to assess the constructs.
