An overview of issues related to categorical and dimensional models of personality disorder assessment.

Despite long-standing efforts to improve the current diagnostic system for Axis II, problems remain with the categorical conceptualization of personality disorders (PDs). Due in part to these problems, interest has developed in dimensional models of PD classification. In this article, we discuss four issues relevant to categorical vs. dimensional assessment of PDs: (a) problems with self-reports in PD patients, (b) methodological issues in behavioral and clinician assessment of PDs, (c) challenges that arise when dimensional models are applied to patient and nonpatient samples, and (d) clinical implications of categorical and dimensional PD models. We suggest that researchers and clinicians address these concerns to avoid implementing a new PD assessment model that-although different from the current system-would otherwise remain fraught with difficulties.