Depressivity as mediator in the fear-avoidance model. A path analysis investigation of patients with chronic back pain

Introduction. The fear-avoidance model (FAM) has gained widespread acceptance as a conceptual framework predicting chronic pain development. However, there is still a high amount of unexplained variance in the prediction of outcome variables. This study aimed to test depression as a mediator of prospective links between the FAM variables pain intensity, pain-related fear, avoidance behavior and disability in order to achieve a better prediction of model variables. Material and methods. Single mediation analyses were conducted using path analysis of longitudinal data from patients with chronic back pain (n=243). Results. There was at least partial mediation by depression for all prospective relations of FAM variables analyzed. The mediation effects increased the percentage of explained variance of the predicted model variables. Conclusion. The findings provide support for additional consideration of depressive symptoms to obtain a better understanding of prospective associations between FAM variables. The findings indicate that in the treatment of chronic back pain following a multiple target approach to reduce pain, pain-related fear and avoidance behavior and also depressive symptoms should be considered.