Abstract—This work represents the first review paper to explore the relationship between perfectionistic personality and borderline personality organization. The developmental origins, identity diffusion, interpersonal difficulties, and defense mechanisms that are common to both borderline personality and the interpersonal components of perfectionism are explored, and existing research on perfectionism and borderline personality is reviewed. The importance of the link between perfectionism and borderline features is discussed in terms of its contribution to the conceptual understanding of personality pathology as well as to applied clinical practices. Keywords—borderline personality organization, defenses, identity, interpersonal problems, perfectionism I. INTRODUCTION ORDERLINE personality disorder (BPD), as classified in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) [1] and borderline personality organization (BPO), as described in the Psychodynamic Diagnostic Manual (PDM) [2] are among the most disruptive, and maladaptive levels of personality pathology that clinicians encounter [3]. While the challenges of understanding and dealing with BPD and the various manifestations of a borderline personality constellation are no stranger to mental health practitioners, one form of personality pathology that has not been widely recognized in relation to BPO is perfectionism. Perfectionism has been studied for decades, and there is a wide range of research suggesting that perfectionism is a personality construct that is associated with a range of intrapersonal, interpersonal, achievement, and somatic problems. Depression, anxiety, eating disorders, personality disorders, difficulties with friendships, intimate relationships, and therapeutic relationships, and suicidality are some of the clinically relevant issues that have been linked with perfectionistic personality [4]. H. M. Roxborough is with the University of British Columbia, Vancouver, BC, V6T 1Z4, Canada (corresponding author: 604-812-5723; e-mail: hrox1@interchange.ubc.ca) P. L. Hewitt is with the University of British Columbia, Vancouver, BC, V6T 1Z4, Canada (e-mail: phewitt@psych.ubc.ca). G. L. Flett is with York University, Tornoto, ON, M3J 1P3, Canada (e- mail: gflett@yorku.ca). More and more researchers are selecting out perfectionism as a relevant personality variable in order to understand its contribution to various forms of psychopathology. Nevertheless, until recently, the severe level of personality pathology that perfectionism is associated with has not been identified or discussed. Despite what is known about perfectionism and psychopathology, the domain of personality pathology and perfectionism has only recently begun to be explored in more depth. What theoretical and empirical work does exist suggests that there is a significant relationship between perfectionism and borderline personality features [5]- [7]. For example the interpersonal components of perfectionism and BPO seem to share common developmental origins, identity problems, interpersonal problems, and splitting defences as well as tendencies towards poor emotion regulation and suicidal behaviour [3]-[4]. Given the severity of borderline characteristics, and the profound impact that borderline personality has on all aspects of an individual’s life and relationships, it is important to understand the role that additional concomitant or underlying personality dimensions may be playing in the development, maintenance, or exacerbation of this degree of personality pathology. The overlap between perfectionism and borderline pathology is consistent with research showing extensive comorbidity of BPD and other Axis II disorders. This suggests that there may be latent structures underlying personality pathology [8]; it is possible that the exploration of similarities in BPO and perfectionism may point towards this underlying “intrapsychic genotype” and its various phenotypic expressions [9]. Following a brief description of perfectionism and borderline personality, the similar etiology, and some of the overlapping symptomatology, particularly identity diffusion, interpersonal problems, and splitting, will be explored. This will be followed by a description of existing research on perfectionism and borderline personality. This review paper represents the first known attempt to clearly situate perfectionism and its related features within the spectrum of borderline pathology. We suggest that there is a clear link between interpersonal components of perfectionism and borderline pathology and suggest that more research should be done to understand the overlap between perfectionism and related borderline features. Understanding Borderline Personality Organization and the Interpersonal Components of Perfectionism: A Review of Two Overlapping Personality Pathologies Heather M. Roxborough, Paul L. Hewitt, Gordon L. Flett, Jasmin Abizadeh B World Academy of Science, Engineering and Technology International Journal of Psychological and Behavioral Sciences Vol:3, No:6, 2009 1180 International Scholarly and Scientific Research & Innovation 3(6) 2009 scholar.waset.org/1307-6892/5598 International Science Index, Psychological and Behavioral Sciences Vol:3, No:6, 2009 waset.org/Publication/5598