Biopsychosocial mechanisms of chronic fatigue syndrome and their relevance for rehabilitation

About 20 000 people in Belgium suffer from chronic fatigue syndrome (CFS), a disorder characterized by persisting fatigue insufficiently explained by known medical or psychiatric conditions. Individuals suffering from CFS experience severe limitations in daily functioning due to their fatigue. Despite intensive research over the past decades, the (psycho)physiological dysfunctions generating CFS symptoms remain poorly understood, and no diagnostic biomarkers for CFS have been identified. Consequently, current treatment options for CFS are limited. Moreover, CFS research has been hampered by emotional dualistic debates about the “psychological” versus “somatic” nature of the disorder, without paying much attention to the possible interactions between physiological and psychological aspects. Dysfunction of several (psycho)physiological systems, such as the neuroendocrine stress response system, the immune system, and the central nervous system (including neuroinflammation and changes in functional connectivity in the brain) has been shown in CFS. Health psychology research, on the other hand, has demonstrated distortions in symptom perception in CFS. However, both research lines have not sufficiently been integrated, which is necessary for an integrative biopsychosocial model of CFS. Because different processes seem to play a role, it is plausible that underlying CFS pathophysiology is not the same for every patient. In this research project we want to test an integrative psychophysiological model of CFS by investigating the relationship between peripheral (psycho)physiological dysfunction (the stress response system, systemic inflammation), brain function (neuroinflammation, functional connectivity) and fatigue perception, both in the lab and in daily life. Further, we want to identify subgroups in CFS pathophysiology based on a combination of these parameter. Finally, we want to investigate how these subgroups relate to rehabilitation success.