Chronic pain and functional impairment: assessing beliefs about their relationship.

Many chronic pain patients believe that they cannot function normally because of their pain. The Pain and Impairment Relationship Scale (PAIRS) was developed to assess the extent to which chronic pain patients endorse this belief, and the relationship of this belief to functional impairment, measured both subjectively and objectively. The PAIRS was administered to 56 patients in a chronic pain treatment program. The PAIRS demonstrated adequate internal consistency and it correlated significantly with another measure of the cognitive component of chronic pain syndrome, the Cognitive Errors Questionnaire--Low Back Scale. The PAIRS accounted for a significant proportion of variance in several measures of impairment (including the Sickness Impact Profile, restrictions in range of motion, and statements of limitation during a standardized exercise routine) beyond that accounted for solely by subjective pain estimate in multiple regression analyses. It appears that the belief that pain necessarily implies disability is associated with actual impairment, independent of the actual contribution of reported pain.