Discussion
somatic distress, bodily weakness, affective, cognitive, and behavioral dimensions, comorbid depression, GS
PMR
In this study, we examined temporal and cross-sectional associations between key elements related to the manifestation of FSS in patients with GS over the course of an 8-week group psychotherapy. Using a systems-perspective to conceptualize treatment-related dynamics, we applied dynamic NA methods and estimated three distinct, complementary networks (temporal, contemporaneous, and between-subject) for symptoms and elements of affective, cognitive, and behavioral dimensions, respectively, to examine the interplay of key elements in each dimension while distinguishing between within-subject and between-subject effects. Our aim was to evaluate the dynamics between symptoms and affect, dysfunctional cognitions, and behavioral-related elements over the course of treatment.There are six key findings of our study: First, temporal networks indicated that GS and affective, cognitive, and behavioral elements were relatively stable over short time periods (i.e., one week) in a treatment context. Second, GS were not temporally predicted by any other elements. Third, we found associations between several dysfunctional cognitions. Notably, catastrophizing cognitions preceded bodily weakness and may indicate a potential causal pathway. In addition, catastrophizing cognitions and bodily weakness fluctuated on a weekly basis and average levels of these cognitions were positively associated with each other. Furthermore, psychological inflexibility showed strong associations on a between-subject level with regard to catastrophizing cognitions and bodily weakness. Fourth, weekly fluctuations of GS were associated with weekly fluctuations of stress. Fifth, GS preceded somatic distress. Sixth, we provided evidence regarding feasibility of dynamic NA in the context of outcome research.Currently, various psychotherapeutic approaches for management of FSS are recommended including CBT and PMR. The therapeutic rationale of these non-pharmacological interventions is primarily to increase overall functioning and copingOur study has several strengths: First, we used data from a prospective study collected on a weekly basis during the psychotherapy period. Second, our study design not only greatly increased the strength of our evidence but also allowed the indication of a temporal sequence. Temporality is one of the nine Bradford Hill criteriaThe following limitations need to be considered: First, dynamic NA techniques in the context of psychology research is relatively new and as described in our Methods section, we followed the process of model selection included using significance pruning and a stepwise up model search strategy outlined in previous literatureWith regards to generalizability, our study is based on data from 100 with a common FSS, GS, that were currently undergoing group psychotherapy. We included patients across a wide range of ages, which increases generalizability. However, our study had several inclusion and exclusion criteria which decreases generalizability of our results to the general population. Furthermore, two thirds of our sample were female and a large proportion of the sample had a higher education (> 50%). These sample characteristics may decrease generalizability. Provided replicability in other indications, our findings may potentially be extended to samples diagnosed with other FSS. Additionally, we collapsed the two treatment groups into one group for reasons outlined in the limitations. It is possible that different treatments lead to different temporal and cross-sectional associations between elements, however, the current study cannot provide clarity to that end. Future studies are needed to explore treatment-specific effects. Relatedly, we would like to address the topic of replicability. Our sample size was modest and NA methods (including dynamic NA) typically require larger sample sizes for stable results. We assessed the stability of the estimated edges by performing 1000 times 25% case-drop bootstraps and found high stability in the contemporaneous networks for all three analyses, as well as in the between-subject network for the analysis examining the association between GS and cognitive elements and the analysis examining the association between GS and behavioral elements. Furthermore, we found moderate stability in the temporal networks for all three analyses and between-subject network for the analysis examining the association between GS and affective elements. It is important to note that since we already had a low sample size, dropping 25% of the sample at random and re-estimating the network model for each analysis likely influenced the stability estimates. We here report all original results and marked all stable edges, as indicated by network stability analyses. However, further studies with larger sample sizes are required before translating results of this line of work into clinical practice, preferably also from other countries and across different FSS.To conclude, in the present study we used a systems perspective to conceptualize treatment-related temporal and cross-sectional associations of symptoms and elements related to the manifestation of a common FSS, GS, as networks of interrelated elements. GS were not predicted by any affective, cognitive, or behavioral elements related to the manifestation of GS over the course of group psychotherapy. However, our findings point towards potential treatment targets for patients with GS that may increase patient’s functioning and coping and further may have an impact on comorbid depression symptom expression. In sum, dynamic network techniques and more importantly their applications for outcome research were feasible yet are still in early stages.