Using the five-factor model to identify a new personality disorder domain: the case for experiential permeability.

Two studies were conducted to demonstrate that maladaptive aspects of high and low Openness to Experience were related to characterological impairment and that this aspect of personality may define a new domain of personality dysfunction. The 55-item Experiential Permeability Inventory (EPI; containing 4 scales) was developed and demonstrated to have acceptable psychometric properties. Evidence of convergent, discriminant, and incremental validity was provided. These studies provide a methodological framework for identifying and developing aspects of personality dysfunction that can expand the comprehensiveness of the current set of Axis II disorders. Theoretical implications of the EPI are discussed.