Assessing the Czech Version of the Inventory of Personality Organization in Relation to Borderline Personality...

This study assessed the Czech version of the Inventory of Personality Organization (IPO-CZ) in relation to borderline personality disorder (BPD) as defined in the ICD-11 model for PDs and defensive functioning in BPDs. The IPO-CZ was used as a proxy measure of personality functioning (PF), although not fully identical to the conception of PF within the ICD-11 framework defined by the severity of self-other impairment.

The IPO-57, Borderline Personality Questionnaire, and Defense Style Questionnaire were administered to general population volunteers (n = 371) and mixed psychiatric patients (n = 293).

Three-factor solution of the IPO-CZ (i.e., Instability of self and others [ISO]; Instability of goals and behaviors [IGB]; and Psychosis) was confirmed, to a large extent reflecting Kernberg's initial concept of personality organization. Since the measurement invariance of the 57-item version was not confirmed across samples, a 14-item version of the IPO-CZ was developed. ISO was strongly associated with self-other pathology in both samples, IGB showed to be an indicator of immature defensive functioning in both samples and mature-neurotic defenses in clinical sample when IPO-14 was used.

While ISO appears to be an indicator of PF in terms of general self-other disturbance, IGB may be considered a specifier of the defense mechanism-based management of impulsive aggression typical of BPD patients that should not be ignored. Moreover, the study found measurement invariance across general and clinical sample for IPO-14.