A clinical utility study of personality inventories: Concordance of the MCMI-III, the MMPI-2, the MMPI-RC, two alternative personality disorder scales, and Axis II discharge diagnosis in psychiatric inpatients

Abstract

The Millon Clinical Multiaxial Inventory and the Minnesota Multiphasic Personality Inventory are two of the most common personality inventories used by clinicians for diagnostic purposes. Discriminant functions of the MMPI-2, MMPI-RC (Restructured Clinical), two alternative MMPI Personality Disorder Scales, and the MCMI-III were compared in a sample of 371 hospitalized psychiatric patients with Axis II discharge diagnoses. Participants were grouped by Cluster B Personality Disorders (93), Cluster C Personality Disorders (38), and participants without an Axis II diagnosis (240). Diagnostic utility of the instruments was compared in regards to DSM-IV-TR Axis II diagnoses. Analyses included utilizing discriminant function analysis to evaluate the diagnostic accuracy of each personality inventory. Further analyses provided information on two diagnostic validity statistics which included: positive predictive power (PPP) and incremental validity of positive test diagnoses (IPPP). The diagnostic validity statistics were used to evaluate which instrument has the most clinical and diagnostic utility in the differentiation of psychopathology. Analyses indicated that each of the instruments effectively predicted group membership at a rate better than chance and that no single instrument performed better or worse in this task. However, the MCMI-III possessed the greatest diagnostic validity as defined by the PPP and IPPP statistics. Thus, the initial hypothesis that the MCMI-III would have the most clinical utility in the assessment of personality disorders is partially supported.