Obsessive relational intrusion and partner violence rise in a graded pattern across the borderline personality spectrum, study finds

People with borderline personality disorder and even those with subthreshold borderline personality traits show markedly higher levels of obsessive relational intrusion and intimate partner violence than healthy individuals, according to a cross-sectional study of 488 participants in Zanjan, Iran. The findings, published in the journal Borderline Personality Disorder and Emotion Dysregulation, support a dimensional model of interpersonal dysfunction in which pathological relationship behaviors intensify stepwise across the borderline spectrum rather than appearing only at the level of a full categorical diagnosis.

The research team, led by Faezeh Baghaei, Omid Saed, Soleiman Saberi, Zahra Karimi and Elnaz Mousavi, set out to examine the relationship between two pathological interpersonal components within the borderline personality spectrum.

Participants were recruited through referrals from psychiatrists and clinical psychologists, inpatient and outpatient psychiatric centers, and online platforms, using purposive sampling. The researchers divided the sample into three groups: individuals with a diagnosis of borderline personality disorder, individuals with borderline personality traits who did not meet the full disorder threshold, and a healthy individuals comparison group. Group classification was based on the Standardized Assessment of Borderline Personality, followed by diagnostic interviews using the Structured Clinical Interview for DSM Axis I disorders and the corresponding Axis II interview, ensuring that the three groups reflected genuinely different positions on the spectrum rather than self-reported labels.

Statistical analysis relied on Welch’s one-way analysis of variance, a variant of the standard ANOVA that does not assume equal variances across groups, together with the Games-Howell post hoc test, which allows pairwise group comparisons when variance homogeneity cannot be assumed. The analyses were carried out in SPSS version 24.

The results showed a consistent graded pattern across the spectrum: participants with borderline personality disorder scored highest, those with borderline personality traits fell in the middle, and healthy individuals scored lowest, for both obsessive relational intrusion and intimate partner violence. In statistical terms, the study found a BPD greater than BPT greater than HI ordering, indicating that each step toward the diagnostic end of the spectrum was accompanied by an increase in these pathological relational behaviors.

Not every interpersonal outcome increased with the same intensity. Obsessive relational intrusion exhibited the largest effect size of the variables examined, suggesting that persistent unwanted relational pursuit is the behavior most strongly differentiated by position on the borderline spectrum. Within intimate partner violence, psychological aggression increased more markedly than physical assault, meaning that verbally and emotionally coercive behaviors shifted across groups more sharply than physically violent ones.

Importantly, the graded pattern was evident across both perpetration and victimization roles for the major intimate partner violence dimensions. This means the differences between the spectrum groups were not confined to one side of partner conflict: individuals further along the borderline spectrum were more likely both to report enacting and to report experiencing these forms of violence. The authors interpret this bidirectional pattern as supporting a dimensional view of interpersonal dysfunction, in which risk accumulates continuously across the spectrum rather than emerging abruptly at the diagnostic threshold.

The conclusion drawn by the researchers is that borderline pathology is best assessed dimensionally rather than relying solely on categorical diagnosis. Their findings showed an overall graded increase in obsessive relational intrusion, psychological aggression, injury and physical assault moving from healthy individuals through those with borderline traits to those with the full disorder. Notably, even subthreshold borderline personality traits were associated with clinically meaningful interpersonal difficulties, a point the authors argue has direct assessment implications, since people who fall short of full diagnostic criteria may still carry substantial relational risk.

On that basis, the study points toward early identification and intervention as a practical priority. The authors suggest that interventions targeting relational fixation, emotion regulation and maladaptive aggression may prevent escalation toward more severe violence among people positioned along the borderline spectrum. Because the design was cross-sectional, comparing groups at a single point in time rather than following individuals over years, the data establish graded associations across spectrum positions and do not by themselves demonstrate that these interventions will change outcomes; the prevention claim is framed as a clinical implication of the observed pattern rather than a tested treatment effect.

The study also carries methodological limitations typical of its design. Purposive sampling from clinical referrals, psychiatric centers and online platforms means the three groups were assembled for the comparison rather than drawn as a representative population sample, and the reliance on self-report instruments leaves open the possibility of reporting differences between diagnostic groups. Nevertheless, the combination of standardized trait assessment, structured diagnostic interviews and validated measures of both relational intrusion and partner violence gives the comparison a level of diagnostic rigor not always present in spectrum studies, and the consistent ordering across perpetration and victimization roles strengthens the case that interpersonal dysfunction tracks dimensionally with borderline personality severity.

Subject of Research: Graded increases in obsessive relational intrusion and intimate partner violence across the borderline personality spectrum

Article Title: Comparison of obsessive relational intrusion and intimate partner violence in the borderline personality spectrum

Article References: Baghaei, F., Saed, O., Saberi, S., Karimi, Z., & Mousavi, E. (2026). Comparison of obsessive relational intrusion and intimate partner violence in the borderline personality spectrum. Borderline Personality Disorder and Emotion Dysregulation. https://doi.org/10.1186/s40479-026-00374-y

Image Credits: AI Generated

DOI: 10.1186/s40479-026-00374-y

Keywords: borderline personality disorder, borderline personality traits, obsessive relational intrusion, intimate partner violence, psychological aggression, physical assault, dimensional model, cross-sectional study, emotion dysregulation, purposive sampling, perpetration and victimization, Zanjan