A team of researchers from Vrije Universiteit Brussel and the University of Antwerp, in Belgium, found that fibromyalgia increases the disability of Chronic Fatigue Syndrome patients. The study entitled “Associations Between Cognitive Performance and Pain in Chronic Fatigue Syndrome: Comorbidity with Fibromyalgia Does Matter” was recently published in the Pain Physician journal.

Chronic Fatigue Syndrome (CFS) is a debilitating and complex disorder characterized by continuous extreme fatigue that is not alleviated by bed rest, interfering with a person’s well-being. The majority of CFS patients also present widespread and persistent musculoskeletal pain. These symptoms are also the hallmark of fibromyalgia, a chronic disorder of unknown etiology. Fatigue, sleep disturbances, mood disturbances and cognitive dysfunctions are other symptoms shared by CFS and fibromyalgia. Indeed, researchers have shown that CFS patients with and without fibromyalgia have worse cognitive capabilities than healthy persons. In this work, authors investigated the relationship between cognitive performance and self-reported and experimental pain measurements in FCS patients with or without fibromyalgia.

The study included a total of 48 subjects divided into 3 groups: CFS only (18 patients), CFS + fibromyalgia (30 patients) and the healthy control group (30 individuals). Participants completed 3 cognitive performance tests to set their attention, cognitive and memory capacities. Seven days later, participants were subjected to different experimental pain measurements and fill out questionnaires to assess self-reported pain, fatigue and depressive symptoms.

Authors found that CFS patients with comorbid fibromyalgia are the most severely affected, having hyperalgesia, enhanced endogenous pain facilitation, and significantly more depressive symptoms compared to the CFS only and control groups. Significant differences between the CFS + fibromyalgia and the CFS only groups were found only in the case of self-reported pain. These findings suggest that a measure of endogenous pain inhibition might be a predictor of cognitive performance in CFS patient with fibromyalgia, while a self-reported pain measurement could be more useful to predict mental health in FCS patients without fibromyalgia. Authors’ data further confirmed the previously reported heterogeneity within CFS patients. As a final comment, authors suggest that future studies should focus in reducing CFS heterogeneity to unravel and understand the underlying mechanisms of CFS patients’ impairments, which would definitely contribute for the development of efficient guided therapies.