Borderline personality disorder (BPD) is recognized as a complex syndrome, resulting in a heterogeneous diagnostic category. Besides the characteristics of the disorder itself, comorbid disorders play an important role in this complexity. The aim of the study is to analyze the clinical validity of 3 components for BPD Diagnostic and Statistical Manual of Mental Disorders criteria - called affective dysregulation, behavioral dysregulation, and disturbed relatedness - investigating differences in patterns of comorbidity. For this purpose, 365 patients with suspected BPD were included in the study. To test our hypothesis, patients were classified into 5 clusters using a K-cluster analysis to study the clinical validity of the 3 components based on the 3-factor model of BPD. Differences in comorbidity, previous suicide attempts, and self-harm behaviors among the defined clusters were analyzed. Between-cluster differences were observed for Axis I and Axis II disorders as well as in the frequency of suicide attempts and in self-harm behaviors. The study of BPD based on the 3 components seems to be more useful than the study of BPD as a unitary construct to help further our understanding of this complex disorder. In the present study, the 3 BPD components have allowed us to analyze the complex comorbidity of BPD patients. This solution could be considered an interesting way to clarify BPD etiology, diagnosis, and treatment efficacy. © 2013 Published by Elsevier Inc. All rights reserved.