Empirical assessment of functional somatic disorder (FSD): frequency, applicability, and diagnostic refinement in a population-based sample

Abstract Background Persistent and troublesome physical symptoms are common and can, regardless of their cause, greatly impair patients’ quality of life. Reflecting complex brain-body interactions, they are observed across all healthcare specialties, commonly overlap across them, and receive inconsi...

Full description

Saved in:
Bibliographic Details
Main Authors: Abigail Smakowski, Judith Rosmalen, Bernd Löwe, Christopher Burton, Anne Toussaint
Format: Article
Language:English
Published: BMC 2025-04-01
Series:BMC Medicine
Subjects:
Online Access:https://doi.org/10.1186/s12916-025-04042-w
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849699469363249152
author Abigail Smakowski
Judith Rosmalen
Bernd Löwe
Christopher Burton
Anne Toussaint
author_facet Abigail Smakowski
Judith Rosmalen
Bernd Löwe
Christopher Burton
Anne Toussaint
author_sort Abigail Smakowski
collection DOAJ
description Abstract Background Persistent and troublesome physical symptoms are common and can, regardless of their cause, greatly impair patients’ quality of life. Reflecting complex brain-body interactions, they are observed across all healthcare specialties, commonly overlap across them, and receive inconsistent diagnoses. In response, the international research network EURONET-SOMA has proposed a diagnostic classification for persistent and troublesome symptoms entitled “functional somatic disorder (FSD)”. Focusing on symptom patterns across organ systems, the FSD approach aims to enhance diagnosis, treatment, and healthcare access for patients. However, further research is needed to validate its effectiveness and clinical utility. This study assessed the frequency and applicability of the FSD proposal within a population-based sample. Methods FSD diagnostic criteria were cross-sectionally operationalised within the multi-disciplinary prospective cohort study Lifelines, conducted in the Dutch population. Kruskal–Wallis and chi-square tests with effect size estimates were used to investigate differences in the diagnostic subgroups regarding chronic diseases, functional comorbidities and psycho-behavioural features. Binary logistic regression with elastic net penalisation was used to investigate sociodemographic, psycho-behavioural and clinical factors associated with FSD. Results Of the study population (N = 88,925), 58% met the diagnostic criteria for FSD. Of those meeting FSD, 31% reported a single distressing symptom, 18% had several symptoms attributable to one organ system and 52% reported multiple symptoms from various organ systems. Moderate differences between these subgroups were found for health status, neuroticism, long-term life difficulties and healthcare utilisation. Elastic net regression showed comorbid chronic musculoskeletal (OR 1.8), gastrointestinal disease (OR 1.4), neurological disease (OR 1.2), and female sex (OR 1.2) predicted FSD. Concurrent anxiety (OR 1.6), healthcare visits (OR 1.3) and long-term difficulties (OR 1.2) were associated with the presence of FSD. Conclusions This study supports refining the FSD criteria to avoid over-inclusiveness. Current symptom severity and frequency thresholds need adjustment to better identify those needing treatment. The distinction between single and multiple symptom categories is important, and optional specifiers like comorbid chronic diagnoses and psychological factors seem valuable for predicting FSD. Despite warranting further research, the FSD classification is promising for diagnosing persistent and troublesome symptoms across medical specialties.
format Article
id doaj-art-fdad08e1f2bc4e85bff556de875cdf0b
institution DOAJ
issn 1741-7015
language English
publishDate 2025-04-01
publisher BMC
record_format Article
series BMC Medicine
spelling doaj-art-fdad08e1f2bc4e85bff556de875cdf0b2025-08-20T03:18:34ZengBMCBMC Medicine1741-70152025-04-0123111510.1186/s12916-025-04042-wEmpirical assessment of functional somatic disorder (FSD): frequency, applicability, and diagnostic refinement in a population-based sampleAbigail Smakowski0Judith Rosmalen1Bernd Löwe2Christopher Burton3Anne Toussaint4Department of Psychosomatic Medicine and Psychotherapy, University Medical Center Hamburg-EppendorfDepartments of Psychiatry and Internal Medicine, University of Groningen, University Medical Center GroningenDepartment of Psychosomatic Medicine and Psychotherapy, University Medical Center Hamburg-EppendorfSheffield Centre for Health & Related Research, School of Medicine & Population Health, University of SheffieldDepartment of Psychosomatic Medicine and Psychotherapy, University Medical Center Hamburg-EppendorfAbstract Background Persistent and troublesome physical symptoms are common and can, regardless of their cause, greatly impair patients’ quality of life. Reflecting complex brain-body interactions, they are observed across all healthcare specialties, commonly overlap across them, and receive inconsistent diagnoses. In response, the international research network EURONET-SOMA has proposed a diagnostic classification for persistent and troublesome symptoms entitled “functional somatic disorder (FSD)”. Focusing on symptom patterns across organ systems, the FSD approach aims to enhance diagnosis, treatment, and healthcare access for patients. However, further research is needed to validate its effectiveness and clinical utility. This study assessed the frequency and applicability of the FSD proposal within a population-based sample. Methods FSD diagnostic criteria were cross-sectionally operationalised within the multi-disciplinary prospective cohort study Lifelines, conducted in the Dutch population. Kruskal–Wallis and chi-square tests with effect size estimates were used to investigate differences in the diagnostic subgroups regarding chronic diseases, functional comorbidities and psycho-behavioural features. Binary logistic regression with elastic net penalisation was used to investigate sociodemographic, psycho-behavioural and clinical factors associated with FSD. Results Of the study population (N = 88,925), 58% met the diagnostic criteria for FSD. Of those meeting FSD, 31% reported a single distressing symptom, 18% had several symptoms attributable to one organ system and 52% reported multiple symptoms from various organ systems. Moderate differences between these subgroups were found for health status, neuroticism, long-term life difficulties and healthcare utilisation. Elastic net regression showed comorbid chronic musculoskeletal (OR 1.8), gastrointestinal disease (OR 1.4), neurological disease (OR 1.2), and female sex (OR 1.2) predicted FSD. Concurrent anxiety (OR 1.6), healthcare visits (OR 1.3) and long-term difficulties (OR 1.2) were associated with the presence of FSD. Conclusions This study supports refining the FSD criteria to avoid over-inclusiveness. Current symptom severity and frequency thresholds need adjustment to better identify those needing treatment. The distinction between single and multiple symptom categories is important, and optional specifiers like comorbid chronic diagnoses and psychological factors seem valuable for predicting FSD. Despite warranting further research, the FSD classification is promising for diagnosing persistent and troublesome symptoms across medical specialties.https://doi.org/10.1186/s12916-025-04042-wFunctional somatic disorderFunctional symptomsPersistent somatic symptomsPersistent physical symptomsFunctional disorderDiagnosis
spellingShingle Abigail Smakowski
Judith Rosmalen
Bernd Löwe
Christopher Burton
Anne Toussaint
Empirical assessment of functional somatic disorder (FSD): frequency, applicability, and diagnostic refinement in a population-based sample
BMC Medicine
Functional somatic disorder
Functional symptoms
Persistent somatic symptoms
Persistent physical symptoms
Functional disorder
Diagnosis
title Empirical assessment of functional somatic disorder (FSD): frequency, applicability, and diagnostic refinement in a population-based sample
title_full Empirical assessment of functional somatic disorder (FSD): frequency, applicability, and diagnostic refinement in a population-based sample
title_fullStr Empirical assessment of functional somatic disorder (FSD): frequency, applicability, and diagnostic refinement in a population-based sample
title_full_unstemmed Empirical assessment of functional somatic disorder (FSD): frequency, applicability, and diagnostic refinement in a population-based sample
title_short Empirical assessment of functional somatic disorder (FSD): frequency, applicability, and diagnostic refinement in a population-based sample
title_sort empirical assessment of functional somatic disorder fsd frequency applicability and diagnostic refinement in a population based sample
topic Functional somatic disorder
Functional symptoms
Persistent somatic symptoms
Persistent physical symptoms
Functional disorder
Diagnosis
url https://doi.org/10.1186/s12916-025-04042-w
work_keys_str_mv AT abigailsmakowski empiricalassessmentoffunctionalsomaticdisorderfsdfrequencyapplicabilityanddiagnosticrefinementinapopulationbasedsample
AT judithrosmalen empiricalassessmentoffunctionalsomaticdisorderfsdfrequencyapplicabilityanddiagnosticrefinementinapopulationbasedsample
AT berndlowe empiricalassessmentoffunctionalsomaticdisorderfsdfrequencyapplicabilityanddiagnosticrefinementinapopulationbasedsample
AT christopherburton empiricalassessmentoffunctionalsomaticdisorderfsdfrequencyapplicabilityanddiagnosticrefinementinapopulationbasedsample
AT annetoussaint empiricalassessmentoffunctionalsomaticdisorderfsdfrequencyapplicabilityanddiagnosticrefinementinapopulationbasedsample