The MMPI-2 Restructured Clinical (RC) Scales and Personality Assessment in Multiple Sclerosis

Multiple sclerosis (MS) is a demyelinating central nervous system disease commonly accompanied by mood changes and cognitive deficits. The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) is frequently used in MS but has been criticized for its inclusion of items referring to neurologic content. MS patients may accurately endorse physical symptoms, which may lead to multiple scale elevations due to the extensive item overlap across the MMPI-2 Clinical Scales. Many published studies have documented elevations on Scales 1, 2, 3, 7, and 8 in MS. In 2003, Tellegen et al. used factor analysis and a construct validity-guided approach to adapt the MMPI-2 and create a set of Restructured Clinical (RC) Scales that included 388 items. The RC scales have attracted significant attention, with evidence of improved psychometric properties, but also criticism about their conceptual foundations and applications. This study had three broad goals. The first was to compare psychometric properties in the RC and Clinical Scales in an MS sample. Secondly, profiles were examined to compare the association between somatic symptoms and the RC and Clinical Scales. Third, the relationship between cognitive dysfunction and the RC and Clinical Scales was investigated. Scores from the RC and Clinical Scales and several cognitive measures were examined from 84 patients in an outpatient neuropsychology clinic. Results showed higher item-total correlations and lower inter-scale correlations for the RC Scales compared to the Clinical Scales, although internal consistency coefficients were comparable or better for the Clinical Scales. Thus, internal consistency findings were mixed with regard to improvement for the RC Scales, while some evidence of higher discriminant validity was found. Somatic and cognitive symptoms were associated with higher Clinical Scale elevations compared to their RC counterparts, particularly on Scales 1, 2, 3, 7, and 8, which were clinically significant in this sample. Mean RC Scale scores were within normal limits with the exception of RC1 (Somatic Complaints), indicating less psychopathology in the sample than the Clinical Scales would suggest. Findings support the need for cautious interpretation of Clinical Scale profiles in MS and suggest that the RC Scales may be a useful measure with this population.