The validity of the MMPI with multiple sclerosis patients.

Prior research findings have suggested that physical illness is a factor that can affect patients' scores on the MMPI. In this study, responses of patients (N = 83) with diagnosed multiple sclerosis, (MS) were compared with those of the original MMPI control group. MMPI items were categorized as either representing the physical effects of MS or not being related to the physical effects of MS. Item and scale analysis indicated that for MS patients, endorsement of items that reflected the neurological disease process led to artificial elevation of four clinical scales. The authors concluded that physical illness should be considered as an independent factor that can influence the validity of MMPI interpretations.