Behavior genetics of personality disorders: informing classification and conceptualization in DSM-5

Personality pathology is currently captured in the Diagnostic and Statistical Manual through 10 categorical personality disorder (PD) diagnoses grouped into three descriptive clusters. This classification system has been criticized by many for using discrete categories and arbitrary thresholds when making clinical decisions. To address these critiques, the DSM-5 Personality and Personality Disorders Work Group has put forth a proposal that significantly alters the structure and content of the DSM-IV PD section. If this DSM-5 Work Group has conducted its own systematic review of the empirical literature, this review has not been released or made widely available. As such, it is up to the psychology community at large to determine how well the suggested changes align with findings from extant PD research. The current article joins this effort by addressing the contribution of behavior genetic findings to the revision process for classification of PDs in DSM-5. First, we provide a brief review of the history of PD classification in the DSM. Next, we present an overview and rationale for each of the five major suggested changes to PD diagnoses. For each suggested change, we outline the available evidence from behavior genetics and interpretations of these findings. Finally, we offer a summary of considerations for PD classification as the DSM-5 moves forward. Review of the behavior genetics literature suggests that several features of the DSM-5 proposal, including the elimination of 4 PDs, merging clinical disorders and PDs on a single axis, and the implementation of a trait rating system, require significantly greater explication before a product is finalized.