This chapter reviews how personality disorder assessment, conceptualization, and treatment can be enhanced by considering interpersonal models. Contemporary Integrative Interpersonal Theory (CIIT) provides conceptual grounding to interpersonal models, which are often constructed around the two dimensions of agency and communion. Agency captures the theme of achievement, status, control, and differentiation, whereas communion captures the theme of connectedness, union, solidarity, and friendship. The authors discuss how personality disorder patients often struggle with agency and communion, and review research articulating how personality disorders are associated with specific impairments in agency and communion in cross-sectional and longitudinal research designs. They also propose a fifth assumption to CIIT to integrate emerging literature on pathological interpersonal patterns in personality disorders. This assumption emphasizes the importance of context in characterizing non-normative social exchanges beyond simple deviations from complementarity. They conclude by discussing how concepts in interpersonal models can be used to inform and implement therapy for patients with a personality disorder.

This rejoinder discusses four areas for growth articulated by the commentaries provided on the initial chapter. The authors add greater specificity for how interpersonal styles can inform therapy approaches. They discuss how static and dynamic conceptualizations of personality disorder can be approached from an interpersonal framework. They agree with Durbin about the importance of relationship context and discuss how interpersonal models can be applied to specific relationship contexts. Finally, they reassert the importance of context in understanding interpersonal processes, while recognizing that “context” is embedded through many of the interpersonal assumptions.

Sanislow and Hector (this volume) provided a comprehensive review of the Cluster C personality disorders (PDs) with an emphasis on articulating anxious-fearful pathology and avoidance behavior. The authors provided historical context for the Cluster C PDs within the DSM and reviewed relevant research findings with a particular focus on how Cluster C pathology can be understood within NIMH RDoC domains. There is much to appreciate in their chapter and this commentary offers points intended to augment their review of Cluster C pathology. It is suggested that interpersonal theory provides a useful framework for understanding personality pathology and a review of relevant research investigating interpersonal functioning in Cluster C PDs is provided.