Uncovering personality structure with the Inventory of Personality Organization : An exploration of factor structure with a Portuguese sample

The Inventory of Personality Organization (IPO) is a self-report measure intended to assess the severity of personality disturbance according to Otto F. Kernberg's model. To study factor structure and psychometric properties of the Portuguese version of IPO (IPO-Pt). Two independent samples of 586 individuals each were used for exploratory and confirmatory factor analyses. Different models were compared in terms of reliability and validity. A three-factor solution resulted, comprising dimensions labeled as Instability of Self, Instability of Others, and Psychosis. Internal consistency and temporal stability yielded acceptable to excellent results. Correlations with measures of self-concept coherence, emotion dysregulation, psychoticism, symptom severity, and personality disturbance were as expected, and sensitivity to clinical status was confirmed. IPO-Pt shows encouraging psychometric qualities and its latent structure resonates with important aspects of Kernberg's model, previous findings, and the DSM-5 level of personality functioning scale.