Background: Borderline Personality Disorder (BPD) is a psychiatric condition characterized by impulsivity, affect instability, dysregulation, low self-image, and interpersonal difficulties. There are many instruments to measure traits of BPD, however, few can be administered quickly. The Screening Instrument for Borderline Personality Disorder (SI-Bord) is an instrument offering a brief administration time with comparable psychometric properties to more comprehensive measures. The present study aimed to evaluate the psychometric properties of the SI-Bord in a healthy community-based sample and its relatedness to measures of social cognition. Methods: A community-based sample of participants completed an online survey consisting of measures of BPD traits and social cognition including: the Screening Instrument for Borderline Personality Disorder (SI-Bord), the Personality Assessment Inventory (PAI), the Florida Affect Battery (FAB), the Interpersonal Reactivity Index (IRI), and the Narcissistic Personality Inventory (NPI). Reliability was assessed using Cronbach’s alpha and inter-item correlations. Validity was assessed using factor analysis, examining associations with other measures of BPD traits, and examining associations with measures not measuring BPD traits. Results: 151 participants were included in the study. Participants’ age ranged from 20−76 (mean age of 38.79 ± 12.37) and comprised 76 females (50.33%) and 75 males (49.67%). Good internal consistency was found with a Cronbach’s alpha of 0.71. Good inter-item reliability was found with a mean inter-item cross correlation of 0.25, with each item of the SI-Bord showing an inter-item correlation coefficient of >0.5. Factor analysis identified good construct validity with a strong singular dimension explaining a large proportion of variance (Question 1). The SI-Bord showed good concurrent validity with significantly strong positive correlations with the subscales of the PAI borderline scale measuring affect instability (r = 0.60; p < 0.001), identity problems (r = 0.67; p < 0.001), negative relationships (r = 0.61; p < 0.001), total score (r = 0.76; p < 0.001), and to a moderately strong positive correlation with self-harm (r = 0.39; p < 0.001). The SI-Bord was not correlated with the NPI-16 (r = 0.131; p = 0.11), showing good divergent validity. Conclusions: These findings support the SI-Bord as a quick and useful screening tool for traits associated with BPD. Further clinical validation is warranted.
Keywords: SI-Bord; borderline personality disorder; screening validation; social cognition.