The use of the McGill Pain Questionnaire in assessing arthritis pain.

Responses to the McGill Pain Questionnaire (MPQ) were described in two samples of arthritis patients, an inpatient group (n = 94) and an outpatient group (n = 94). Subjects in both samples used a similar set of sensory words to describe their arthritis pain. The inpatient sample, however, used affective words of higher intensity than the outpatient sample. Because the two samples came from a common population, they were combined and exploratory factor analyses using principal component analysis with first oblique and then orthogonal rotations were performed. The analysis yielded 6 factors that accounted for 58.3% of the variance in the sample. Clear sensory factors, an affective factor and an evaluative factor were identified. The study provides preliminary evidence that a substantial affective dimension underlies the MPQ responses of arthritis patients and confirms the parsimony of a 3-factor solution for the questionnaire.