Objective:Although reducing pain catastrophizing has been shown to contribute to functional improvement in patients receiving interdisciplinary pain care, little is known about how changes in the different dimensions of pain catastrophizing uniquely contribute to improvement in outcome. The study examined the unique relationship between changes in the 3 distinct factors of pain catastrophizinghelplessness, rumination, and magnificationand changes in pain outcomes.Materials and Methods:In this nonrandomized study, 641 patients who completed treatment in a 3-week interdisciplinary pain rehabilitation program between the years 2013 and 2014 completed a battery of psychometrically validated measures of pain catastrophizing, pain severity, pain interference, mental and physical health-related quality of life, and depressive symptoms at pretreatment and posttreatment.Results:A series of within groups (repeated measures) mediation analyses were conducted. Change in the helplessness, rumination, and magnification subscales were entered as multiple mediators in the model. Analyses revealed that change in helplessness partially mediated improvement in all outcome variables beyond the influence of change in other variables in the model, whereas change in rumination partially mediated improvement in pain severity, interference, and depressive symptoms. Change in magnification had the least impact on outcome, partially mediating improvements in only mental health quality of life.Discussion:Results suggest that changes in the 3 dimensions of pain catastrophizing differentially mediate improvement in pain outcome. Treatment approaches that specifically target helplessness and rumination may be particularly useful in improving the outcomes of patients with refractory pain conditions enrolled in interdisciplinary pain rehabilitation program.