The Inventory of Personality Organization: psychometric properties, factorial composition, and criterion relations with affect, aggressive dyscontrol, psychosis proneness, and self-domains in a nonclinical sample.

This report describes 2 studies of the psychometric characteristics of the primary clinical scales of the Inventory of Personality Organization (IPO; O. F. Kernberg & J. F. Clarkin, 1995), which assess reality testing, primitive psychological defenses, and identity diffusion, in a nonclinical sample. The 3 IPO scales display adequate internal consistency and good test-retest reliability. Item-level confirmatory factor analysis supported a two-factor structure of the IPO consistent with O. F. Kernberg's (1984, 1996) model of borderline personality organization. Each of the 3 IPO scales was associated with increased negative affect, aggressive dyscontrol, and dysphoria as well as lower levels of positive affect consistent with Kernberg's model of borderline personality organization. The IPO Reality Testing scale is closely related to various measures of psychotic-like phenomena.