Objectives:
Although the multifactorial nature of chronic pain is well established, research has predominantly examined isolated variables or singular pathways that may contribute to this condition. We use a complex systems perspective to examine the interplay of psychological factors in the context of chronic pain.

Methods:
We analyzed 2 cross-sectional data sets (N=935 and 1366) collected at a pain clinic and rehabilitation center in Belgium from individuals primarily with musculoskeletal pain. These included self-reported data on pain-related fear and avoidance beliefs, depression and anxiety symptoms, pain intensity, and disability. We used Gaussian Graphical Models to examine conditional associations between these variables, their relative importance (having more/stronger relationships), and how they are moderated by pain-related fear and pain intensity.

Results:
Our analyses revealed highly interrelated networks, with several unique, positive associations between the included factors. Depressive symptoms and pain intensity were most strongly related to pain disability. Fear-avoidance beliefs featured less prominently than previous studies looking at this concept in isolation have suggested. Apart from differences in 2 associations between samples, and 2 moderation effects of pain intensity in 1 sample, the network structure was similar across the 2 samples.

Discussion:
Overall, our results show that psychological factors related to disability have intricate interrelations, highlighting the complexity of chronic pain and the need to study its many components in relation to each other. The consistency across the 2 samples provides encouraging evidence that the results reflect a stable pattern within this complex system.