The MMPI-2 restructured clinical (RC) scales and measurement of depression in epilepsy

Abstract

This study examined the Restructured Clinical (RC) Scales of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) in a sample of 137 patients with epilepsy. The purposes of the current study were (1) to provide information regarding the psychometric performance of the RC Scales in an epilepsy population, and (2) to examine interpretive characteristics of the RC Scales in an epilepsy population. Internal consistency, internal discriminant validity, and external discriminant and convergent validities were assessed for select RC Scales. Results indicated that the RC Scales showed a modest improvement in general psychometrics over the Clinical Scales. Specifically, the RC Scales displayed slightly better internal consistency and lower scale intercorrelations. Using the Inventory of Depressive Symptomatology, Self Report (IDS-SR) as a criterion, RCd ("demoralization") outperformed RC2 ("low positive emotions") and Scale 2 ("Depression") in predicting depressive severity. Throughout this study, results consistently indicated a close relationship between RC Scales measuring depression, anxiety, and health symptoms; this relationship seemed to reflect comorbidity of symptoms rather than substantial construct overlap. Additionally, several subgroups were defined based on Clinical Scale scores (i.e., a "conversion V" group, a "floating profile" group), and IDS-SR scores; RC Scale scores were examined in these groups. Subjects who demonstrated the conversion V profile tended to have large elevations on RC1 in the absence of comparable elevations on RCd and RC2, and a low score on RC3. Those with a floating profile showed only slight elevations on RCd, RC1 ("health complaints"), RC2, and RC8 ("aberrant experiences"). Subjects classified as at least moderately depressed using the IDS-SR, had only mild elevations on RCd and RD8, with highest elevation for RC1. In summary, the RC Scales showed acceptable performance in this sample, though they were differentially elevated in comparison to the Clinical Scales, indicating that even slight elevations on the RC Scales should be carefully considered in interpretation.