Is there a role of depressive symptoms in the fear-avoidance model? A structural equation approach.

The fear-avoidance (FA) model has gained widespread acceptance as a conceptual framework for investigating psychological factors such as FA beliefs and avoidance behavior, which contribute to chronic back pain and reduced functioning. Depressive symptoms are supposed to be related to FA beliefs and to foster avoidance behavior. This study aims to investigate the multivariate assumptions of the FA model with a focus on the role of depressive symptoms. A total of N = 360 patients with chronic nonspecific low back pain at admission of inpatient orthopedic rehabilitation participated in the survey. Measures included a numeric pain rating scale, Fear-Avoidance Beliefs Questionnaire, Pain Anxiety Symptoms Scale, Hannover Functional Ability Questionnaire and Patient Health Questionnaire. Using structural equation modeling (SEM), we construed a basic FA model and subsequently extended it by adding symptoms of depression as a covariate. The results of SEM indicated a good model fit for a basic FA model (χ²(263) = 431.069, p < .001, RMSEA = .042, CFI = .964, WRMR = .986). They confirmed the hypothesized relations and supported single mediations of the relationship between pain and functioning by FA beliefs and avoidance behavior. A second model including symptoms of depression as additional covariate (χ²(511) = 722.761, p < .001, RMSEA = .034, CFI = .956, WRMR = .949) showed a high impact of depressive symptoms on all FA model variables leading to a decrease of the FA mediations. The findings provide empirical support for the multivariate FA model and underline the importance of considering depressive symptoms in a multiple-target approach to understand the mechanisms of chronic pain.