Dimensions of depression and psychopathy in psychiatric inpatients: contribution of the RC scales

Abstract

While depression and psychopathy have long been believed to be mutually exclusive traits, a number of MMPI-2 studies have found relatively high correlations between the original Depression and Psychopathic Deviate Scales. This high degree of covariation might be accounted for by the often observed result that all of the basic nine scales of the MMPI-2 are saturated with a general negative affect factor called demoralization. Recently, a series of studies were completed in which this demoralization factor was extracted from the original basic nine scales and they were restructured such that they would each be a more "pure" measure of the clinical dimensions they were intended to assess. These new scales are called the Restructured Clinical (RC) Scales.

The major purpose of this study was to examine the items found on the original Depression and Psychopathy Scales for multidimensionality and item overlap, and to compare these scales with their RC counterparts. It was assumed that there would be little if any covariation of the RC Depression and RC Psychopathic Deviate Scales as has been found with the original Depression and Psychopathic Deviate Scales.

A factor analysis of the items from each scale was done. Results showed that the original scales indeed had significant item overlap as well as multidimensionality. In addition, the new RC Scales were shown to be much purer in their measurement of their respective constructs.

This study provides strong support for the practice of including at least these two scales in the clinical assessment of depression and psychopathy. It would appear that these restructured scales have met the goal of refining the measurement of these two dimensions.