INTRODUCTION Special Section: Self-Other Distinction in Personality Disorders INTRODUCTION

Problems with self- and interpersonal functioning are defining features of personality disorders (PDs) that seem to stem from impairments in self-other distinction (SOD), that is, the sociocognitive capacity to distinguish between one's own and others' mental and physical experiences. There has been recent renewed interest in this topic across a wide range of fields, from clinical psychology to social neuroscience and experimental psychology. This special section on "Self-Other Distinction in Personality Disorders" is therefore very timely, particularly given the shift to dimensional views of personality pathology with an emphasis on impairment in self and relatedness. In this editorial, we first summarize the various research traditions concerning the potential role of SOD impairment in PDs, including recent advancements in social neuroscience and experimental psychology focusing on the mechanisms that might underlie SOD. We then discuss the main contributions of the five highly innovative articles in this special section. Together, these articles highlight the potential value of a focus on PDs through the lens of SOD impairments in order to better understand key features of this group of disorders, such as emotional contagion, perspective-taking difficulties, blurred embodied self-other boundaries, and self-other coordination difficulties. Our increasing insights into SOD problems can also be expected to increase the effectiveness of treatments for PDs and related conditions. Yet, much work remains to be done in this area, and we end this editorial by discussing a number of potential avenues for translational research in this regard.