Pain perception and personality measures as discriminators in the classification of fibrositis.

Twenty patients with fibrositis were compared to age and sex matched groups of patients with rheumatoid arthritis (RA) and normal controls regarding personality variables measured by the Basic Personality Inventory (BPI) and responsiveness to experimentally induced pain. The group with fibrositis scored significantly higher than the normal group on 4 of the BPI scales and had lower pain threshold and tolerance than the normal group. The group with RA was found to be significantly different from the normal group on hypochondriasis and pain tolerance. Using only pain and personality measures, a statistical discriminant function that was developed resulted in a 72% classification accuracy for the 3 groups studied and 85% accuracy when only the 2 clinical groups were considered.