The Role and Function of Acceptance and Commitment Therapy and Behavioral Flexibility in Pain Management

KEYWORDS :

• acceptance and commitment therapy
• behavioral flexibility
• chronic pain
• cognitive behavior therapy
• pain interference

Despite recent advances, the high prevalence and debilitating effects of chronic pain remains [1]. Pharmacological and surgical strategies are often insufficient in alleviating symptoms or increasing functioning [2]. Although pain tends to significantly interfere with activities across multiple domains (e.g., vocational, social, physical), traditional pain management has to an important extent focused on reducing pain and distress, leaving pain interference as a somewhat neglected dimension. However, pain interference has historically been a key target for behavioral interventions [3], and recent research supports the notion that pain interference is critical for daily functioning and future health [4].

Acceptance & commitment therapy & behavioral flexibility

Acceptance and commitment therapy (ACT) is a relatively novel treatment approach developed within a contextual behavioral science framework. ACT has gained increased attention and empirical support particularly in the field of chronic pain during the past decade.

From an ACT perspective a narrow and inflexible behavior pattern characterized by avoidance of pain and distress plays a central role in the development and maintenance of disability and reduced quality of life [5]. Hence, the treatment objective is to develop a wider and more flexible behavior repertoire, or to increase behavioral flexibility (also referred to as psychological flexibility), defined as the ability to act in accordance with personally held values also in the presence of interfering pain and distress. Notably, this implies that ACT is not primarily about reducing pain intensity but rather its influence on behavior, that is, pain interference.

Similar to other behavior therapies, ACT is an exposure-based treatment in which the patient is encouraged to engage in personally important activities previously avoided due to pain and distress. In this process, acceptance (or willingness to experience) is promoted as a behavioral response to pain and distress that cannot be directly changed, to facilitate engagement in activities that are meaningful although possibly painful. Also, the patient is encouraged to disengage, or ‘step back’ from, verbal processes (i.e., thoughts), to decrease their impact on behavior (denoted as cognitive defusion). Although exposure may be a central ingredient in other and more traditional variants of cognitive behavior therapy, the objective or function, in ACT is different. Rather than altering responses through extinction or habituation, the primary objective is to increase behavioral skills such as acceptance and defusion. This, in turn, will facilitate the development of a wider and more flexible behavior repertoire in the presence of pain and distress, and engagement in activities that bring meaning, quality, vitality and the like into one’s life.

Relational frame theory

In ACT, as a contextual behavioral model, persistent pain can be seen as interoceptive stimuli (stimuli produced within an organism) that can influence the probability of behavioral responses. In this model, the stimulus function (or psychological function) of pain is central for the analysis. This means that a behavioral response such as saying no to a social event is not directly related to the level of intensity but rather its function, or meaning, to the individual in that particular context [6].

As described by relational frame theory, the theoretical framework underlying ACT, stimulus functions are continuously acquired via direct experiences, but also through their relations with other stimuli [5]. This implies that a behavioral response is not due to just one stimuli but rather the relational network of stimuli. Pain as an interoceptive stimulus is associated with a large number of other stimuli, and the actions taken depend on the psychological function(s) of that relational network of stimuli. A seemingly trivial situation may therefore elicit very strong reactions due to the associations being made: a relatively modest pain sensation from the neck trigger thoughts like “pain in the neck is bad,” which in turn are related to ideas such as “it may be a fragile disk,” and “something is terribly wrong,” that eventually lead to fatalistic conclusions like “I will end up in a wheelchair.” Thus, even if the initial stimulus is modest, it may activate a relational network of stimuli with very aversive psychological functions.

Importantly, the activation of such relational frameworks is often involuntary. In fact, efforts to control them (e.g., trying not to think about the fragile disk) may result in a paradoxical increase of both frequency and intensity of these thoughts [7], which further motivates avoidance. Conversely, an acceptance-oriented approach would aim to reduce unsuccessful control efforts and broaden the behavioral repertoire, such that effective values-based action can occur. In addition to a wider and more flexible behavior repertoire, acceptance-oriented exposure may, over time, affect the psychological experience. Exposure to previously avoided situations and activities also facilitate new learning. New experiences will add information to existing relational networks, and new associations are made. The incorporation of other, and possibly contrasting, information may modify the relational network and, consequently, the stimulus functions. For example, an individual participating in a social event previously avoided may achieve several new experiences that result in important associations that contribute to the existing relational network. Even if subsequent situations still elicit thoughts like ‘I cannot do this,’ such associations are part of a richer network of associations that now include ‘It feels like last time, and then I made it; it can be meaningful, even if it hurts; worst case I can leave early, they will understand.’ And, the influence of such additional associations may alter the stimulus function of that pain sensation; not necessarily changing the intensity but possibly the ‘threat value’ of it.

Empirical support for behavioral flexibility & ACT

The importance of behavioral flexibility is supported in a large number of studies [8]. For example, it has been shown that greater acceptance of chronic pain is associated with less avoidance of important activities, better emotional well being and less healthcare utilization [9]. Also, behavioral flexibility has been shown to be a key factor in the relation between symptoms and disability [10] and between catastrophizing and pain-related distress [11].

The empirical support for ACT has increased rapidly during the past decade, particularly in the area of chronic pain, and ACT is today listed by the American Psychological Association’s Division of Clinical Psychology, as an empirically supported treatment for chronic or persistent pain in general [12]. In short, treatment evaluations have illustrated the utility of ACT with both adult [13,14] and pediatric [15] patients, in individual [16] and group [14] settings, in extensive residential multimodal rehabilitation settings [13] as well as in more brief outpatient interventions [14]. Data also suggest that effects are relatively stable through follow-ups of as long as 3 years [17].

Also, a sizeable number of studies have evaluated the mediating function of behavioral flexibility in ACT for pain. In two studies, the importance of improvements in behavioral flexibility was shown to be a more important mediator than symptom alleviation, decreased catastrophizing and improved self-efficacy (i.e., the specificity criteria) [18,19]. Also, studies have illustrated that changes in behavioral flexibility precede improvements in outcome, that is, the temporality criteria [20]. Furthermore, behavioral flexibility has been shown to function as a mediator across a wide range of outcome variables [14,21].

Future research & development

Importantly, ACT and behavioral flexibility is not a destination but rather a promising direction for future research and development. Particularly, although the utility and change processes of ACT are fairly well known, research thus far has failed to identify salient predictors or moderators of treatment outcome [17], which implies that we do not know if there are certain patient characteristics or other factors that may influence the effects of treatment. While this limitation is certainly not restricted to ACT (e.g., see [2]), successful prediction of treatment outcome is a key area for future work to investigate.

Also, despite strong research evidence, the accessibility of ACT is low. As a consequence, a large number of patients suffering from chronic pain do not have access to this treatment. To meet the growing demand for ACT requires new treatment forms. Internet-based treatments have successfully been developed in several other domains, and recent research has shown that these interventions have effects comparable with standard face-to-face treatments [22]. There is still a scarcity of studies evaluating internet-delivered ACT for chronic pain, but a few studies with promising results exist [23,24]. This development may significantly increase the possibilities to make ACT as an evidence-based treatment widely available, but more research is clearly needed.

Furthermore, there is an urgent need to explore and evaluate the utility of ACT and behavioral flexibility in a number of different areas. First, although behavioral flexibility may be conceptualized as a transdiagnostic factor it is yet to be empirically evaluated if the importance of behavioral flexibility varies across different pain types or diagnoses. Second, studies should explore if ACT-strategies can be used to improve the patients’ ability to manage pain and distress that result from repeated medical procedures, as in cancer treatment. Third, no study has yet explored the role of behavioral flexibility in the transition from acute to chronic pain. For example, future research should investigate the utility of the ACT model in predicting and preventing the development of chronic postsurgical pain and disability. Fourth, little is yet known regarding the role and influence of biological processes involved in ACT-oriented interventions, and more research in this area is urgently called for. To investigate the role of brain activity patterns in the prefrontal cortex, we used functional neuroimaging in a recent a randomized controlled trial evaluating ACT for females diagnosed with fibromyalgia. Although tentative, results illustrate that patients treated with ACT had increased activations in the ventrolateral prefrontal/lateral OBFC (vlPFC/OBFC) during pressure-evoked pain as compared with a waitlist control condition [25]. Previous research has suggested that the vlPFC/OBFC is involved in executive cognitive control. Notably, this implies that the altered brain activity patterns correspond with ACT theory and warrants more studies to further evaluate if changes in vlPFC/OBFC reflects improvements in behavioral flexibility.

In conclusion, an increasing amount of research suggests the utility of ACT and behavioral flexibility in pain management. Bearing that success in mind, more research is still needed to clarify for whom, in what circumstances and how it should be used.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.