Empirical evaluation of the MCMI-III personality disorder scales

The MCMI-III personality disorder scales were empirically validated with a sample of 870 clinical patients and inmates. Prevalence rates of personality disorders were in general lower on the MCMI-III than clinical ratings, but trait prevalence was generally higher; thus a base rate of 75 on the MCMI-III could be a guideline in the screening of trait prevalence. However, the sensitivity of some MCMI-III scales was very low. Moreover, the correlations of most personality disorder scales of the MCMI-III were significant and positive with corresponding measures on clinical ratings and MMPI-2 personality disorder scales, but these were, in general, not significantly higher than some other correlations. As a consequence the discriminant validity seems to be questionable. The MCMI-III alone cannot be used as a diagnostic inventory, but the test could be useful as a screening device as a part of a multimethod approach that allows aggregation over measures in making diagnostic decisions.