Fear-avoidance model of chronic musculoskeletal pain: 12 years on.

It is widely acknowledged that pain is a universal experience that affects human beings across the life span, serving an important protective function. Typical protective behaviors are the withdrawal from the noxious stimulus, nonverbal expressions that signal others for impending harm, and verbal utterances. Some of these occur involuntarily, as a reflex, whereas other behaviors are more deliberate. However, there is accumulating evidence that it is not pain itself, but the meaning of pain that predicts the extent to which individuals engage in these protective behaviors [1,3]. About a decade ago, we summarized the research evidence supporting the role of fear of pain in the development of chronic pain disability, presented a model incorporating basic mechanisms, but also noted a number of unresolved issues that called for further scientific attention [39] (Fig. 1). In the last decade, the number of studies on this subject has increased exponentially [21], and novel directions are being proposed [6]. Two main stances have emerged. First, although pain has intrinsic threatening features, the threat value of similar pain stimulus may vary across contexts and individuals. Second, protective responding may be adaptive in the short term, but may paradoxically worsen the problem in the long term. In the current updated review, we briefly summarize the progress made since, and highlight a selected number of remaining challenges and areas for future research.