Elaborating on the construct validity of the Minnesota Borderline Personality Disorder Scale (MBPD): a multi-sample,...

Borderline personality disorder (BPD) is frequently conceptualized as an extreme variant of normal personality traits. A previous study successfully developed and validated a self-report BPD measure, the Minnesota Borderline Personality Disorder Scale (MBPD). We conducted 2 studies aimed at providing further validation for this measure. Results from Study 1 (clinical sample of substance users) indicated that the MBPD exhibited strong positive correlations with measures of convergent validity. In addition, the MBPD showed similar correlations with external correlates as those of the convergent validity measures as well as incremental utility in predicting these external correlates above and beyond negative affect and adult antisocial behavior. Also, a receiver operating characteristic curve analysis indicated that diagnostic accuracy of the MBPD was excellent for differentiation between BPD and non-BPD individuals. Likewise, Study 2 (nonclinical sample of undergraduate students followed over 6 months) showed strong correlations with an index of convergent validity, similar correlations with external correlates as that of the convergent validity index, and incremental predictive utility. Finally, in this study, the MBPD exhibited high rank-order stability. These data provide further evidence that the MBPD is a valid indicator of BPD.