Toward a Model for Assessing Level of Personality Functioning in DSM–5, Part II: Empirical Articulation of a Core Dimension of Personality Pathology

Abstract

The extensive comorbidity among Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM–IV]; American Psychiatric Association, 1994) personality disorders might be compelling evidence of essential commonalities among these disorders reflective of a general level of personality functioning that in itself is highly relevant to clinical decision making. This study sought to identify key markers of such a level, thought to reflect a core dimension of personality pathology involving impairments in the capacities of self and interpersonal functioning, and to empirically articulate a continuum of severity of these problems for DSM–5. Using measures of hypothesized core dimensions of personality pathology, a description of a continuum of severity of personality pathology was developed. Potential markers at various levels of severity of personality pathology were identified using item response theory (IRT) in 2 samples of psychiatric patients. IRT-based estimates of participants’ standings on a latent dimension of personality pathology were significantly related to the diagnosis of DSM–IV personality disorder, as well as to personality disorder comorbidity. Further analyses indicated that this continuum could be used to capture the distribution of pathology severity across the range of DSM–IV personality disorders. The identification of a continuum of personality pathology consisting of impairments in self and interpersonal functioning provides an empirical foundation for a “levels of personality functioning” rating proposed as part of a DSM–5 personality disorder diagnostic formulation.