The Borderline Personality Disorder Severity Index-IV: Psychometric evaluation and dimensional structure

The BPDSI-IV is a DSM-IV based semi-structured interview that assesses frequency and severity of Borderline Personality Disorder (BPD) manifestations during the last three months. The present study assessed its psychometric properties and underlying factor structure. Data from 108 BPD-patients, 31 Cluster-C PD patients, 27 Axis-I patients and 76 non-patients were analyzed. Interrater reliability, internal consistency, discriminant, construct and concurrent validity proved to be very good. Clinical norms with high sensitivity and specificity were derived. Confirmatory factor analyses supported both a one and nine-dimensional model based on the DSM-IV criteria. The nine-factor model was superior over 7 alternative models. In conclusion, the BPDSI-IV is a reliable and valid instrument to assess BPD-severity as well as severity of the nine DSM-IV BPD-criteria separately.