Symptom Perceptions in Functional Disorders, Major Health Conditions, and Healthy Controls: A General Population Study.

Background: The present study investigated differences in symptom perceptions between individuals with functional disorders (FD), major health conditions, and FDs + major health conditions, respectively, and a group of healthy individuals. Furthermore, it investigated the relevance of FDs among other health-related and psychological correlates of symptom perceptions in the framework of the Common Sense Model of Self-Regulation (CMS). Method: This cross-sectional study used epidemiological data from the Danish Study of Functional Disorders part two (N = 7,459 participants, 54% female, 51.99 ± 13.4 years). Symptom perceptions were assessed using the Brief Illness Perception Questionnaire (B-IPQ) and compared between the four health condition groups. Multiple regression analyses were performed to examine associations between symptom perceptions, FDs, and other health-related and psychological correlates from the CMS framework. Results: Individuals with FDs (n = 976) and those with FDs + major health conditions (n = 162) reported less favorable symptom perceptions compared to the other two groups, particularly regarding perceived consequences, timeline, and emotional representations (effect size range Cohen's d = 0.12-0.66). The presence of a FD was significantly associated with all B-IPQ items, even in the context of 16 other relevant health-related and psychological correlates from the CMS framework, whereas symptom presence last year or last week was not. Conclusion: In the general population, symptom perceptions seem to play a more salient role in FD than in individuals with well-defined physical illness. Symptom perceptions should therefore be targeted in both primary and secondary interventions for FDs.