Comparative analysis of MMPI form R and MMPI-168 profiles in low back pain patients

This study investigated the efficacy of MMPI Form R in evaluating chronic low back pain patients. Ninety-seven males and 81 females were administered Form R during a pre-treatment evaluation. Each test was scored for Form R and MMPI-168. Scales Pa and Sc were re-scored following a modified conversion table discussed in the literature, resulting in three scores for Pa and Sc. Correlations were calculated between scales on the two forms plus modified conversions for scales Pa and Sc. Highly significant correlations were found between the two forms of the MMPI, with slightly lower correlations between modified Pa and Sc scales and the same scales on Form R. Although there were statistical differences between MMPI Form R and MMPI-168 profile elevations, these were not considered clinically significant. Because of the high intercorrelations, and the test length it seems possible to consider use of the MMPI-168 in screening chronic pain patients. Other hypotheses exploring sex differences and differential profile elevations were investigated and are discussed.