BackgroundThe aim of the study was to examine the reciprocity between pain catastrophizing, social participation and quality of life outcomes (pain intensity, pain disability, negative affectivity) in patients with low back pain in a multidisciplinary pain treatment.MethodsPatients undergoing inpatient rehabilitation were surveyed at the beginning and two weeks after the end of rehabilitation. N = 262 low back pain patients participated (mean age: 52.2, 62.1 % female). A two-wave cross-lagged design and structural equation modeling were used to analyze data.ResultsWe found evidence of reciprocal relations with regard to several outcomes. For example, pain catastrophizing at the beginning of treatment is associated with negative affectivity after rehabilitation, and the post-treatment value of pain catastrophizing is associated with pain disability and satisfaction with participation at the start of treatment. Pain disability and pain catastrophizing are predictors of lower treatment outcome while pain intensity and negative affectivity are not risk factors. Participation stands in a reciprocal relationship with some of the pain treatment outcomes. The surprising result, namely, that those patients more satisfied with social participation experience less improvement regarding catastrophizing, can be explained by ceiling effects and the Communal Coping Model.ConclusionsThis study provides evidence of the importance of taking reciprocal relations among pain catastrophizing, social participation and other pain outcomes into account. Providers of multidisciplinary pain treatment need to play attention to patients at risk with high disability and catastrophizing thoughts. Pain treatment would benefit from closer integration of psychosocial measures to foster social participation.