Role of stressors in adult fibromyalgia – a response to Kaleycheva et al.

Dear Editor, Kaleycheva et al. (2021) undertook a review and meta-analysis of case-controlled studies with the aim of distilling out whether factors such as lifetime stressors impacted on the risk of developing fibromyalgia in adulthood. The authors were attracted to study this as they had been influenced by previous research indicating that there was growing evidence in support of this hypothesis. From their analysis the authors concluded that they were able to confirm a strong relationship between lifetime stressors and the development of fibromyalgia in adulthood, particularly for those who had experienced physical abuse. However, Kaleycheva et al. (2021) and colleagues fall short in several domains to critically address and account for crucial limitations in their systematic review and meta-analysis which may mean that their conclusions are perhaps not as strong as they claim. Rather unfortunately, this may lead to an exaggeration of the extent of the relationship suggested. Furthermore, there appears to be a lack of consideration regarding the direction of causality. Of greatest concern, is the absence of critical examination of the well-known difficulties posed by the research methods used in the 19 studies included within the analysis. All the case−control studies included within the meta-analysis used interviews or questionnaires which elicited people’s retrospective experiences and memories over their lifespan. The purpose of memory is as a system or process that stores what we experience to allow us to use it in the future. In essence, it is the retention of data to allow its use to predict future actions. Relying on patient’s retrospective, autobiographical memory is troublesome from several perspectives. Firstly, autobiographical recollection varies among individuals over a period of weeks, let alone decades (Berntsen, Hoyle, & Rubin, 2019). Recollection of memories is highly influenced by the recaller’s internal state at the time of recollection (Bower, 1981). Further, this mood congruent recall is therefore likely to exaggerate the memories of previous painful and emotional times if fibromyalgia patients are prompted to recall such. Negative events in everyday life often include more dominant and intrusive details which are seen through a more negative lens in memory (Congleton & Berntsen, 2020). Sadly, stressful life events are so ubiquitous to being alive and human that they are rather the norm. Together, evidence from memory research highlights that it is exceedingly likely that a relationship will be found between being in pain currently and the prompting to recall painful memories of past event(s). In summary, patients with fibromyalgia will have more availability of access to previously distressing events in their memory. However, there is no convincing evidence presented in this meta-analysis that the relationships discovered are no more than a response to simply being in pain. Furthermore, no direction of causation can be determined from cross-sectional research designs and retrospective self-report methods. It can perhaps help to tease out the complex relationship that, as expected, people experiencing on-going pain and debility will have greater access in recall and are therefore more likely to report previous painful experiences. This is important for the well-being, adjustment and coping of patients with chronic pain. The authors set the scene in the second paragraph whereby they define fibromyalgia in their view as a functional disorder aligned with a psychosomatic or somatoform condition and causation. This is puzzlingly presented here as though this is an established and agreed upon consensus within the field of fibromyalgia research and clinical practice. This is far from the case. Unfortunately, such possible bias leads the study away from considering alternative models and views of fibromyalgia and is at odds with pain researchers and clinicians working with persistent pain in the field. In essence, without explaining alternative conceptualisations the paper perhaps loses credibility and, in this case, may lead to the researcher’s confirmation bias of their own held views on the matter. There is no attention given within the paper that living with a chronic pain condition, such as fibromyalgia, can in itself be stressful, exhausting, debilitating, and can be distressing and traumatic potentially leading to hypothalamic−pituitary−adrenal (HPA) disruption as a consequence, not a cause. As symptoms of fibromyalgia vary greatly day to day, and the HPA-research findings are inconsistent, it is likely that this is at least in part responsible for the variability in the research findings. Psychobiological mechanisms have not been elucidated nor objectively observed (Nater, Fischer, & Ehlert, 2011). At best, the HPA-dysfunction hypothesis of chronic pain remains speculative.