Multidimensional Pain Inventory derived classifications of chronic pain: evidence for maladaptive pain-related coping within the dysfunctional group.

This study examines maladaptive pain-related fear-avoidance and endurance coping in subgroups of patients with chronic back pain. Hypotheses were derived from the avoidance-endurance model of pain [Hasenbring M. Attentional control of pain and the process of chronification. In: Sandkühler J, Bromm B, Gebhart GF, editors. Progress in pain research, vol. 129. New York: Elsevier; 2000. p. 525-34.], which assumes that endurance coping (cognitive, behavioral tendency to endure severe pain to finish current activities irrespective of pain increases) leads to overuse of muscles, joints, and discs with an increase of pain as long-term consequence. Participants were 120 patients referred for treatment of chronic pain to General Practices. They were classified as 'dysfunctional-DYS' (15.8%), 'interpersonally distressed-ID' (10.8%), and 'adaptive copers-AC' (61.7%) based on the Multidimensional Pain Inventory [Kerns RD, Turk DC, Rudy TE. The West Haven-Yale Multidimensional Pain Inventory (WHYMPI). Pain 1985;23:345-56.] and compared on measures of pain-related fear-avoidance coping (anxiety/depression; help-/hopelessness; catastrophizing; avoidance of social/physical activity) and endurance coping (positive mood; thought suppression; endurance behavior) using the Kiel Pain Inventory [Hasenbring M. The Kiel Pain Inventory-Manual. Three questionnaire scales for assessment of pain-related cognitions, emotions and copying strategies. Bern:Huber; 1994.]. Multivariate analysis of variance indicated that groups differed significantly for pain-related fear-avoidance and endurance coping, even after control for pain intensity and depression. Univariate effects revealed that patients classified as DYS reported more anxiety/depression, help-/hopelessness, and catastrophizing than did those classified as AC. Furthermore, the DYS group showed more thought suppression compared to AC; however, subgroups did not differ significantly with regard to avoidance of social and physical activity, and endurance behavior. Further, DYS as well as ID group showed more non-verbal pain behavior compared to AC, which refers to the special role of operant conditioning. Implications are considered for further investigation of endurance coping to provide a more comprehensive assessment and treatment for subgroups of chronic pain patients.