The revision of the Diagnostic and Statistical Manual, Fourth Edition (DSM-IV-TR) to DSM-5 provided the opportunity to shift the paradigm for diagnosing personality disorders (PDs) from a polythetic, categorical approach to a dimensional methodology. Although initial and in-progress descriptions of the plans to revise the diagnostic criteria for PDs suggested that there would be an extensive revision, the changes to DSM ultimately reflected a conservative approach. The categorical approach was retained without substantial revision other than to remove the PDs from a separate diagnostic axis. In effect, this decision set the agenda for research and clinical practice for PDs for years to come, with a continued reliance on polythetic categories to define PDs. This chapter provides a broad overview of existing methods for assessment of categorical PDs including the use of self-report scales and structured or semi-structured interviews. The point-of-view presented in this chapter is not that Present/Absent categories are the gold standard for diagnosis, but that they represent current practice in clinical care and (some) research. The major focus will be to evaluate validity and reliability characteristics of these methods. A summary statement that includes recommendations for future research is presented.

The author provides a summary of the commentaries provided by Bornstein (this volume) and Chmielewski and Truilo (this volume), highlighting areas of agreement and cordial disagreement. Broadly speaking, Bornstein sees progress and is optimistic about the direction of change with respect to categorical assessment of PDs, favoring an approach that combines categories and dimensions. In contrast, Chmielewski and Truilo are dissatisfied by the current state of diagnostic assessment of PDs. The author takes the perspective that while there is room for improvement, there has been significant progress in how PDs are conceptualized and assessed.Collaborative research that integrates different perspectives and methodologies is needed to continue to advance the field.