Andy
Senior Member (Voting rights)
Highlights
- Most SSD patients (87%) met criteria for multi-system functional somatic disorder.
- Multi-system FSD showed greater psychological burden than single-system presentations.
- Health anxiety and somatosensory amplification were key associates of multi-system FSD.
- Single-system FSD showed limited overlap with established functional somatic syndromes.
- FSD subgroup classification offers clinically meaningful stratification within SSD.
Abstract
Background
Functional somatic disorders (FSD), characterised by persistent physical symptoms and associated impairment, remain diagnostically fragmented across medical specialties, contributing to inconsistent patient care. The FSD classification addresses this by classifying symptom presentations into multi-system, single-system, and single-symptom subcategories, yet its utility in clinical populations is largely unexamined. This study evaluated the applicability and clinical utility of FSD classification in patients with Somatic Symptom Disorder (SSD).Methods
Observational, cross-sectional analysis of baseline data from the SOMA.SSD cohort. Patients with SSD (N = 239), diagnosed using the Structured Clinical Interview for DSM-5-TR (SCID-5), were recruited from a German psychosomatic outpatient clinic. FSD subcategories were operationalised using the Bodily Distress Syndrome Checklist. Group differences were examined using chi-square and Mann-Whitney U tests, and binary logistic regression identified factors associated with multi-system FSD.Results
Most patients met multi-system FSD criteria (n = 207, 86.6%). Multi-system FSD was associated with greater psychological and behavioural burden, including higher somatosensory amplification, perceived stress, health anxiety, and negative affect, compared with other subgroups. Single-system FSD showed limited correspondence with established syndrome-based diagnoses (e.g., fibromyalgia or irritable bowel syndrome). Comorbid musculoskeletal, vascular, and neurological conditions were common but often not aligned with the presenting symptom system.Conclusions
The FSD classification captured variation within SSD, supporting its value as a complementary tool for characterisation and differentiation. Transdiagnostic factors such as health anxiety, somatosensory amplification, and negative affectivity may play a key role in multi-system presentations. Future research should examine the FSD classification's utility in longitudinal and treatment settings.Paywall