From expectation to experience

Persistent somatic symptoms are common in both general and clinical populations and impose a substantial socioeconomic burden, considerable strain on healthcare systems, and marked psychological distress and functional impairment among affected individuals. Contemporary theoretical models, including cognitive and predictive-processing accounts, have highlighted symptom expectations as central mechanisms in the development and maintenance of persistent somatic symptoms. However, it remains unclear whether expectations are prospectively associated with symptom trajectories in everyday life and which factors are associated with the formation of negative expectations in clinical populations, particularly in patients with somatic symptom disorder, who experience chronic and distressing bodily complaints. This dissertation addresses these gaps by examining the associations between expectations and the course of somatic symptoms, by experimentally manipulating symptom expectations using expectation framing strategies in (1) a healthy student sample and (2) patients with somatic symptom disorder. Furthermore, factors associated with the development of negative expectations in patients with somatic symptom disorder are investigated. In studies I and II, symptom expectations and momentary symptom severity were assessed using smartphone-based ecological momentary assessment (EMA), allowing real-time, ecologically valid insights into symptom dynamics. In Study III, cross-sectional data were analysed to examine the characteristics of symptom-related expectations and the factors associated with their formation in patients with somatic symptom disorder. Study I, a 7-day micro-longitudinal EMA study with n = 104 university students (three assessments/day), examined the association between momentary symptom expectations, self-management experiences and experimentally induced expectation framing on somatic symptom severity. Participants were randomized to either positive or negative expectation framing conditions. Results revealed robust concurrent associations between symptom expectations and somatic symptom severity, as well as higher somatic symptom severity in participants exposed to negative framing. Time-lagged analysis showed that higher symptom expectations predicted subsequent increases in somatic symptom severity levels, indicating small-to-moderate temporal effects. Study II investigated patients with somatic symptom disorder (N = 217) over 10 days (three assessments/day), comparing positive framing to standard information. Symptom expectations and symptom severity showed strong concurrent associations, and symptoms decreased slightly over time. More positive initial expectations were associated with faster improvements in symptom severity. In contrast to Study I, expectation framing did not significantly affect subsequent expectations or symptom trajectories, suggesting that simple framing interventions may be insufficient to alter entrenched expectations in clinical populations. Study III, a cross-sectional investigation of N = 241 patients with somatic symptom disorder, examined the nature and determinants of symptom expectations Most patients reported negative short-term symptom expectations. Patients with more negative symptom expectations were found to experience greater somatic symptom severity, higher depression and anxiety severity, increased symptom-related distress, and higher symptom-related disability. Symptom-related disability, symptom-related distress, depression severity, somatic symptom severity, and somatic comorbidity emerged as key factors associated with the development of negative symptom expectations. Taken together, the results support the central relevance of symptom expectations for momentary and short-term fluctuations in somatic symptom severity and identify important factors associated with the formation of negative expectations in somatic symptom disorder. While the manipulation of symptom expectations…