Objectives: Patients with borderline personality disorder (BPD) often develop a certain depression that may be accompanied by “mental pain.” A negative self-concept, aversive chronic emotions, and pervasive helplessness characterize mental pain. This research aims to explore the pathology of BPD symptomatology in a nonclinical sample. Also, the role of mental pain, cognitive emotion regulation, self-compassion, and depression are assessed. Methods: Following a correlational study, 300 university students were selected via the multi-stage random cluster sampling method. The study data were collected by the personality assessment inventory-borderline features scale, Orbach and Mikulincer mental pain questionnaire, cognitive emotion regulation questionnaire, self-compassion scale (SCS-SF), and Beck depression inventory version 2. Results: Multiple regression analyses indicated that components of putting into perspective, rumination, loss of control, refocus on planning, catastrophizing, irreversibility, somatic, and isolation (ΔR2=0.507, P<0.001) significantly predicted BPD symptomatology. Discussion: The results support the biosocial model dimensions in an Iranian context. In addition, it shows a strong association between mental pain, cognitive emotion regulation, self-compassion, depression, and BPD symptoms.