Eline Coppens, The role of childhood adversities in fibromyalgia: prevalence and relationship to stress reactivity Supervisors: prof. dr. Patrick Luyten, prof. dr. Lukas Van Oudenhove, Co-supervisor: prof. dr. Bart Morlion Dissertation submitted to obtain the degree of Ph.D. in Psychology Patients with fibromyalgia syndrome (FM) suffer from chronic widespread pain (CWP). A history of childhood adversities (ECA) has been shown to elevate the risk to develop FM. The prevalence of ECA in FM typically ranges between 16% and 60%. However, it is not clear whether the prevalence of ECA in FM is different compared to other functional somatic disorders (FSS), and whether and how ECA may play a role in the pathogenesis of these disorders. FSS has been associated with dysfunction of the stress response system. The hypothalamic-pituitary-adrenal (HPA) axis, which plays a central role in stress regulation, in particular might be influenced by psychosocial factors such as ECA, and associated insecure adult attachment strategies and impairments in embodied mentalizing. Therefore, in Chapter 1, we investigated the prevalence of different types of (ECA) and posttraumatic stress disorder (PTSD) features in female FM/CWP patients compared with patients with Functional Dyspepsia (FD), another FSS, and achalasia, a somatic disease. The second aim of this study was to investigate the relationship between ECA and pain severity as well as the possible role of PTSD symptom severity in this relationship. As expected, we found that about half of all FM/CWP patients reported at least one type of ECA. Furthermore, the odds of reporting at least one type of ECA did not differ from the odds in FD patients, but was four times higher compared to achalasia patients. However, the presence or severity of ECA was not related to pain severity. Yet, FM/CWP patients were about 6 times more likely to meet PTSD criteria compared to those with functional dyspepsia (FD) and achalasia. PTSD severity also mediated the relationship between ECA severity and pain severity, despite the lack of a direct relationship between both. In chapter 2, in the same sample of FM/CWP women, we explored possible relationships between both ECA and PTSD symptom severity on the one hand and various indices of psychosocial and physical functioning, on the other. We found that ECA was only associated with depression severity. PTSD symptom severity, by contrast, was highly significantly associated with all indices of physical and psychosocial functioning. Furthermore, relationships among PTSD severity and these indices were mediated by problems with embodied mentalizing, with problems with describing emotions being particularly important. From Chapter 3 onwards, we focused on the neurobiology of FM in relation to psychosocial features typical of these patients. We found a, blunted cortisol responsivity of FM to the Trier Social Stress Test (TSST) compared with healthy controls (HC) without ECA. FM patients had, however, higher subjective stress levels compared with HCs, particularly at baseline and during recovery from the TSST. In FM patients, ECA was not associated with cortisol or subjective stress levels, nor with responsivity to the TSST. These results reflect a dissociation between subjective and cortisol responses to stress in FM. In chapter 4 we found significantly more difficulties with identifying feelings (DIF), but not difficulties with describing feelings (DDF), in FM patients compared to HCs. We did not find any significant differences, however, in adult attachment strategies or emotion processing between FM and HC. Yet, insecure attachment was related to both the cortisol response and subjective distress in the TSST in HC, but not in FM. These latter findings may be related to the observed hypoactivity of the cortisol stress system in FM and high baseline levels of subjective distress in these patients. In conclusion, high levels of ECA in FM/CWP in combination with PTSD features, but not ECA as such, were related to pain severity. This suggests that the impact, rather than the mere presence, of ECA is of crucial importance in determining the influence of ECA on pain severity in FM/CWP. Indeed, PTSD features were associated with all physical and psychosocial functioning indices. Moreover, these relationships were mediated by problems with embodied mentalizing. Finally, we observed a "crash" of the stress system or attenuated resilience in FM compared with HC. Prospective research is needed in this context to further replicate these findings. status: published