Fear-avoidance model of pain
With the introduction of a ‘fear-avoidance model of exaggerated pain perception’ in 1983, Lethem and colleagues reserved a critical role for fear of pain and avoidance behaviour in the explanation of perpetuating pain complaints in the absence of organic pathology (Lethem et al. 1983). In this model, ‘confrontation’ and ‘avoidance’ are postulated as two extreme responses to the fear of pain.
Fig. 14.1 Fear avoidance model of chronic pain. This figure has been reproduced with permission of the International Association for the Study of Pain® (IASP®). The figure may not be reproduced for any other purpose without permission.
While confrontation will lead to the reduction of fear over time, avoidance leads to the maintenance or exacerbation of fear, possible developing into a phobic-like state. The avoidance results in the reduction of both social and physical activities, which in turn can lead to a number of physical and psychological consequences augmenting the disability.
After the introduction of the fear-avoidance model by Lethem and the emphasis on the role of cognitions in avoidance by Philips, various cognitive-behavioural models of chronic pain have been proposed. These models are commonly referred to as contemporary fear-avoidance models, in which pain disability is conceived as the result of a vicious process that is determined by the interaction between cognitions and behaviour (Asmundson et al. 1999; Vlaeyen et al. 1995b; Waddell et al. 1993). Subtle differences aside, contemporary fear-avoidance models all share the same basic tenets, which can be easily understood from the integrated model that is illustrated in Figure 14.1. Upon the initial perception of pain, individuals assign a certain meaning and purpose to the painful experience that is based upon current expectations regarding the pain and prior learning history. Although the majority of individuals will evaluate the pain experience as undesirable and unpleasant at this stage, most persons will not perceive it as an extreme threat or an insurmountable catastrophe. These individuals will proactively and gradually confront their pain, and resume their daily activities, promoting health behaviours and early recovery. However, for a minority of individuals, the painful experiences, which are intensified during movement, will elicit catastrophizing cognitions. These catastrophic cognitions can then lead to pain-related fear (fear of pain, fear of movement, fear of (re)injury), which in its turn initiates the avoidance of potential painful activities and hypervigilance for potential signals of additional pain and bodily harm. As such, a vicious and self-perpetuating spiral is activated with avoidance of more and more (daily) activities, leading to functional disability and possibly also to social isolation and depression. In addition, physical deconditioning and depression may fuel the fear-avoidance cycle by increasing pain intensity and increasing the fearful appraisal of and selective attention to pain. In addition to the avoidance of fearful activities, pain disability may also persist because of the immediate consequences to which it leads, such as diminished pain, increased attention from others, and the avoidance of social conflicts or responsibility.