Review article Fear-avoidance and its consequences in chronic musculoskeletal pain: a state of the art Johan W.S. Vlaeyen a,b, * , Steven J. Linton c a Department of Medical, Clinical and Experimental Psychology, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands b Institute for Rehabilitation Research, Behavioral Rehabilitation Research Program, P.O. Box 192, 6400 AD Hoensbroek, The Netherlands c Department of Occupational and Environmental Medicine, O È rebro Medical Center Hospital, 701-85 O È rebro, Sweden Received 3 November 1998; received in revised form 8 September 1999; accepted 9 September 1999 Abstract In an attempt to explain how and why some individuals with musculoskeletal pain develop a chronic pain syndrome, Lethem et al. (Lethem J, Slade PD, Troup JDG, Bentley G. Outline of a fear-avoidance model of exaggerated pain perceptions. Behav Res Ther 1983;21:401±408) introduced a so-called `fear-avoidance' model. The central concept of their model is fear of pain. `Confrontation' and `avoidance' are postulated as the two extreme responses to this fear, of which the former leads to the reduction of fear over time. The latter, however, leads to the maintenance or exacerbation of fear, possibly generating a phobic state. In the last decade, an increasing number of investigations have corroborated and re®ned the fear-avoidance model. The aim of this paper is to review the existing evidence for the mediating role of pain- related fear, and its immediate and long-term consequences in the initiation and maintenance of chronic pain disability. We ®rst highlight possible precursors of pain-related fear including the role negative appraisal of internal and external stimuli, negative affectivity and anxiety sensitivity may play. Subsequently, a number of fear-related processes will be discussed including escape and avoidance behaviors resulting in poor behavioral performance, hypervigilance to internal and external illness information, muscular reactivity, and physical disuse in terms of deconditioning and guarded movement. We also review the available assessment methods for the quanti®cation of pain-related fear and avoidance. Finally, we discuss the implications of the recent ®ndings for the prevention and treatment of chronic musculoskeletal pain. Although there are still a number of unresolved issues which merit future research attention, pain-related fear and avoidance appear to be an essential feature of the development of a chronic problem for a substantial number of patients with musculoskeletal pain. q 2000 Interna- tional Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved. Keywords: Pain-related fear; Chronic pain; Musculoskeletal pain; Avoidance; Disability 1. Introduction The development of chronic musculoskeletal pain from an apparently `healed' acute injury has baf¯ed researchers and clinicians alike. The fear-avoidance model has recently provided an enticing account of how chronic pain may develop. Pain problems have been viewed as complex, multidimensional developmental processes where various psychosocial factors are of the utmost importance (Skeving- ton, 1995; Gatchel and Turk, 1996). However, it has been dif®cult to speci®cally spell-out the mechanisms by which acute problems become chronic. Thus, the introduction of the so-called `fear-avoidance' model has been a welcomed explanation. Fear-avoidance, which refers to the avoidance of move- ments or activities based on fear, has been put forth as a central mechanism in the development of long-term back pain problems. In particular, fear-avoidance is thought to play an instrumental role in the so-called deconditioning syndrome. Screening and assessment measures have begun to appear, and treatment as well as preventive inter- ventions have been designed that are congruent with the fear-avoidance concept. Some authors have gone so far as to term the phenomenon an irrational fear or phobia, as the source of the danger is often not recognized by the clinician (Kori et al., 1990). However, research on fear-avoidance is very broad and ranges from theoretical analyses to labora- tory and clinical studies. In the last decade, an increasing number of both experimental and clinical studies have shown that fear and anxiety in¯uence the experience of pain, and chronic pain disability in particular. Moreover, the concept involves behavioral, physiological, and cogni- tive aspects of learning. Although a good deal of research has been conducted, it appears to have gaps, especially with Pain 85 (2000) 317±332 0304-3959/00/$20.00 q 2000 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved. PII: S0304-3959(99)00242-0 www.elsevier.nl/locate/pain * Corresponding author. E-mail address: j.vlaeyen@dep.unimaas.nl (J.W.S. Vlaeyen)