Functional somatic syndrome
 | This article needs more reliable medical references for verification or relies too heavily on primary sources, specifically: Primary sources or excessively dated. (July 2025) |
| Functional somatic syndrome | |
|---|---|
| Specialty | Psychiatry |
Functional somatic syndrome (FSS) (sometimes termed "non-specific physical disorders") is a group of symptoms or conditions in which chronic symptoms occur, but no cause is found.[1] Fibromyalgia is the leading FSS condition, among many. Chronic fatigue syndrome has been seen by some as an FSS condition.[2] FSS conditions are highly prevalent, but little is known about their etiology.
Functional somatic syndromes are very common, and are estimated to affect about 8-16% of the general population.[3][4][5]
Definition and Terminology
[edit]FSS refers to disturbances in bodily functioning where aetiology is unknown.[6] The term ‘functional somatic disorders’ (FSD) was proposed in 2020.[7]
Related terms
[edit]"Medically unexplained physical symptoms" only include symptoms where no explanation is found at all, but not poorly understood syndromes like fibromyalgia or IBS. These symptoms can sometimes be worsened in the presence of mental health problems.[8]
"Persistent physical symptoms"[9] includes FSS situations but also situations where persistent physical symptoms are caused by a known illness, such as arthritis.
In "somatic symptom disorder" chronic physical symptoms, which may or may not be linked to a known illness, coincide with excessive and maladaptive thoughts, emotions, and behaviors connected to those symptoms. In FSS these features are not present.
Classification
[edit]This term does not appear in the ICD-11. Proposals for classifications have been made.[10]
Signs and symptoms
[edit]Functional somatic syndromes are characterized by ambiguous, non-specific symptoms that appear in otherwise-healthy people. Overlap in symptomology exists across diagnoses, including gastrointestinal issues, pain, fatigue, cognitive difficulties, and sleep difficulties. Some have proposed to group symptoms into clusters[11][12] or into one general functional somatic disorder given the finding of correlations between symptoms and underlying etiologies.[13]
FSS conditions
[edit]FSS conditions may include:
- chronic fatigue syndrome[14]
- fibromyalgia (FM),[15]
- mold allergy,
- temporomandibular disorder,
- irritable bowel syndrome,[15][16]
- electromagnetic hypersensitivity,
- lower back pain,
- tension headache,
- atypical face pain,
- insomnia,
- long-haul COVID,[17]
- palpitation,
- dyspepsia,
- dizziness,[18]
- unevidenced claims of food allergies,[15]
- Gulf War syndrome,[15]
- undemonstrable hypoglycaemia (with symptoms appearing when the blood sugar is normal),[15]
- chronic Lyme disease,[15]
- multiple chemical sensitivity,[15]
- sick building syndrome,[15]
- chronic whiplash[15]
Overlap of FSS conditions
[edit]A considerable overlap of symptoms exists between the FSS diagnoses, with high rates of comorbidity between them. For example, the prevalence of comorbid FSS diagnoses ranges from 20% to 70%, while comorbid affective disorders with a fibromyalgia diagnosis ranges from 20% to 80%.[19]
Prevalence
[edit]Studies have found prevalence in the general population of having at least one FSS of 16.3% (n = 9656),[20] and 9.3% (n = 3054).[21]
Some 10% of the general population, and around 33% of adult patients in clinical populations, suffer from functional somatic symptoms.[22]
Potential causes
[edit]A mixture of physical and psychological factors may predict FSS.[1][10]
Psychological factors
[edit]Low-quality evidence suggests that patients with somatic syndromes, such as fibromyalgia and irritable bowel syndrome, tend to have a more frequent history of both physical and sexual abuse prior to the onset of their physiological symptoms. Additionally, patients show higher rates of previous emotional abuse, emotional neglect, and physical neglect when compared to the general population.[23]
Attentional bias has been posited as the psychological mechanism by which trauma and somatic symptoms are tied.[24][25][unreliable medical source?] Attentional bias refers to the idea that traumatic events can cause individuals to become more attuned to their bodily functions, thus intensifying the perception of pain, fatigue, and other common somatic symptoms.[25][unreliable medical source?] The initial traumatic event is interpreted as a threat to the body, and therefore the stress response of the body takes on a new, heightened awareness to any potential subsequent threats. This attentional bias leads to health anxiety, wherein the patient becomes increasingly concerned that common somatic symptoms are related to a physical disease or injury, and therefore, another potential bodily threat.[24][unreliable medical source?] An initial perception of lost control can further intensify attentional bias; sense of control is negatively associated with symptom reporting, suggesting that somatic symptoms are more closely monitored when psychologically recovering from an incident of lost control.[26][unreliable medical source?] Functional somatic syndromes are thought to be a result of conditioned hyperarousal following a trauma; victims are conditioned to respond more sensitively to the somatic symptoms following a trauma by their attention to and reinforcement of the symptom existence. This feedback loop is similar to that of panic disorder, in which fear of a subsequent panic attack causes an increased hyper-vigilance towards, and exacerbation of, physiological symptoms, such as heart palpitations, dizziness, and breathlessness.[27][unreliable medical source?]
Biological factors
[edit]One hypothesis implicates the hypothalamic–pituitary–adrenal axis (HPA axis) in the manifestation of somatic symptoms following trauma. The HPA axis plays a major role in moderating the body's stress response to both emotional and physical pain, relating to both the experience of psychological symptoms prevalent following trauma as well as the physiological symptoms prevalent in FSS conditions.[28] When an individual experiences a traumatic event, the HPA axis causes the increased release of cortisol, activating the sympathetic nervous system and causing negative feedback to be sent to the hypothalamus and pituitary gland. In people who have experienced major trauma, this reaction can become dysfunctional and can cause a chronic decrease in cortisol production, though the rates of this decrease in cortisol levels vary across different types and frequencies of trauma.[29]
Diagnosis
[edit]Diagnosis of a FSS is usually a diagnosis of exclusion, where physicians rule out other disorders that could explain the dysfunctions being experienced.[30]
Management and Treatment
[edit]CBT can be helpful for FSS. Medications such as antidepressants may play a role.[31][32] More direct medication has little if any positive long-term impact.[1]
According to guidance from the German Federal Ministry of Health "the extent to which functional somatic syndromes affect people’s lives partly depends on how the people affected deal with them."[1]
History
[edit]The term functional somatic syndrome was used in a 1999 paper.[33]
References
[edit]- ^ a b c d "Functional somatic syndromes: treatment". gesund.bund.de. Dec 15, 2023.
- ^ Geraghty KJ, Esmail A (2016-08-01). "Chronic fatigue syndrome: is the biopsychosocial model responsible for patient dissatisfaction and harm?". British Journal of General Practice. 66 (649): 437–438. doi:10.3399/bjgp16X686473. ISSN 0960-1643. PMC 4979914. PMID 27481982.
- ^ Madsen MM, Trolle C, Fynne LV, Colombo M, Pedersen RL, Sørensen VN, et al. (November 2025). "Early identification of functional somatic disorders in an internal medicine diagnostic clinic: The DISTRESS trial". Contemporary Clinical Trials. 158 108082. doi:10.1016/j.cct.2025.108082. PMID 40972891.
- ^ Rometsch C, Mansueto G, Maas Genannt Bermpohl F, Martin A, Cosci F (June 2024). "Prevalence of functional disorders across Europe: a systematic review and meta-analysis". European Journal of Epidemiology. 39 (6): 571–586. doi:10.1007/s10654-024-01109-5. ISSN 0393-2990. PMC 11249491. PMID 38551715.
- ^ Petersen MW, Schröder A, Jørgensen T, Ørnbøl E, Dantoft TM, Eliasen M, et al. (July 2020). "Prevalence of functional somatic syndromes and bodily distress syndrome in the Danish population: the DanFunD study". Scandinavian Journal of Public Health. 48 (5): 567–576. doi:10.1177/1403494819868592. ISSN 1651-1905. PMID 31409218.
- ^ Donnachie E, Schneider A, Enck P (2020). "Comorbidities of Patients with Functional Somatic Syndromes Before, During and After First Diagnosis: A Population-based Study using Bavarian Routine Data". Scientific Reports. 10 (1) 9810. Bibcode:2020NatSR..10.9810D. doi:10.1038/s41598-020-66685-4. PMC 7299983. PMID 32555301.
- ^ Burton C, Fink P, Henningsen P, Löwe B, Rief W (2020). "Functional somatic disorders: Discussion paper for a new common classification for research and clinical use". BMC Medicine. 18 (1): 34. doi:10.1186/s12916-020-1505-4. PMC 7052963. PMID 32122350.
- ^ "Medically unexplained symptoms". nhs.uk. October 15, 2025.
- ^ Löwe B, Toussaint A, Rosmalen JG, Huang WL, Burton C, Weigel A, et al. (June 15, 2024). "Persistent physical symptoms: definition, genesis, and management". The Lancet. 403 (10444): 2649–2662. doi:10.1016/S0140-6736(24)00623-8. PMID 38879263 – via www.thelancet.com.
- ^ a b Burton C, Fink P, Henningsen P, Löwe B, Rief W (2020). "Functional somatic disorders: discussion paper for a new common classification for research and clinical use - PMC". BMC Medicine. 18 (1): 34. doi:10.1186/s12916-020-1505-4. PMC 7052963. PMID 32122350.
- ^ Fink P, Schröder A (May 2010). "One single diagnosis, bodily distress syndrome, succeeded to capture 10 diagnostic categories of functional somatic syndromes and somatoform disorders". Journal of Psychosomatic Research. 68 (5): 415–426. doi:10.1016/j.jpsychores.2010.02.004. PMID 20403500.
- ^ Lacourt T, Houtveen J, van Doornen L (January 2013). ""Functional somatic syndromes, one or many?" An answer by cluster analysis". Journal of Psychosomatic Research. 74 (1): 6–11. doi:10.1016/j.jpsychores.2012.09.013. PMID 23272982.
- ^ Wessely S, White PD (August 2004). "There is only one functional somatic syndrome". The British Journal of Psychiatry. 185 (2): 95–96. doi:10.1192/bjp.185.2.95. PMID 15286058.
- ^ Fischer S, Kleinstäuber M, Fiori LM, Turecki G, Wagner J, von Känel R (2023). "DNA Methylation Signatures of Functional Somatic Syndromes: Systematic Review". Psychosomatic Medicine. 85 (8): 672–681. doi:10.1097/PSY.0000000000001237. ISSN 1534-7796.
- ^ a b c d e f g h i "2.2 The Putative Disappearance of Somatic Manifestations of Hysteria", From Photography to fMRI, transcript Verlag, pp. 219–237, 2022-12-31, doi:10.1515/9783839461761-009, ISBN 978-3-8394-6176-1,
In the late 1990s, it became a matter of heated debate if hysteria's nosological successors were conceptually and diagnostically distinguishable from a range of possibly related clinical conditions that were equally characterised by the lack of any demonstrable physical abnormality. Jointly referred to as functional somatic syndromes, these conditions include multiple chemical sensitivity, sick building syndrome, chronic fatigue syndrome, fibromyalgia, irritable bowel syndrome, chronic whiplash, chronic Lyme disease, the Gulf War syndrome, food allergies, hypoglycaemia. To this date, the delineation between present-day forms of hysteria and other functional somatic syndromes remains unresolved.
- ^ Afari N, Ahumada SM, Wright LJ, Mostoufi S, Golnari G, Reis V, et al. (January 2014). "Psychological trauma and functional somatic syndromes: a systematic review and meta-analysis". Psychosomatic Medicine. 76 (1): 2–11. doi:10.1097/PSY.0000000000000010. PMC 3894419. PMID 24336429.
- ^ Joffe AR, Elliott A (2023-01-01). "Long COVID as a functional somatic symptom disorder caused by abnormally precise prior expectations during Bayesian perceptual processing: A new hypothesis and implications for pandemic response". Sage Open Medicine. 11 20503121231194400. doi:10.1177/20503121231194400. ISSN 2050-3121. PMC 10467233. PMID 37655303.
- ^ Mayou R, Farmer A (August 2002). "ABC of psychological medicine: Functional somatic symptoms and syndromes". BMJ. 325 (7358): 265–268. doi:10.1136/bmj.325.7358.265. PMC 1123778. PMID 12153926.
- ^ Häuser W, Kosseva M, Üceyler N, Klose P, Sommer C (June 2011). "Emotional, physical, and sexual abuse in fibromyalgia syndrome: a systematic review with meta-analysis". Arthritis Care & Research. 63 (6): 808–820. doi:10.1002/acr.20328. PMID 20722042.
- ^ Petersen MW, Schröder A, Jørgensen T, Ørnbøl E, Dantoft TM, Eliasen M, et al. (July 1, 2020). "Prevalence of functional somatic syndromes and bodily distress syndrome in the Danish population: the DanFunD study". Scandinavian Journal of Public Health. 48 (5): 567–576. doi:10.1177/1403494819868592. PMID 31409218.
- ^ Fischer S, Gaab J, Ehlert U, Nater UM (June 1, 2013). "Prevalence, overlap, and predictors of functional somatic syndromes in a student sample". International Journal of Behavioral Medicine. 20 (2): 184–193. doi:10.1007/s12529-012-9266-x. PMID 23055025.
- ^ Roenneberg C, Sattel H, Schaefert R, Henningsen P, Hausteiner-Wiehle C (Aug 9, 2019). "Functional Somatic Symptoms". Deutsches Ärzteblatt International. 116 (33–34): 553–560. doi:10.3238/arztebl.2019.0553. PMC 6794707. PMID 31554544.
- ^ Yavne Y, Amital D, Watad A, Tiosano S, Amital H (August 2018). "A systematic review of precipitating physical and psychological traumatic events in the development of fibromyalgia". Seminars in Arthritis and Rheumatism. 48 (1): 121–133. doi:10.1016/j.semarthrit.2017.12.011. PMID 29428291. S2CID 205143853.
- ^ a b Golding JM (March 1994). "Sexual assault history and physical health in randomly selected Los Angeles women". Health Psychology. 13 (2): 130–138. doi:10.1037/0278-6133.13.2.130. PMID 8020456.
- ^ a b Carleton RN, Duranceau S, McMillan KA, Asmundson GJ (April 2018). "Trauma, Pain, and Psychological Distress". Journal of Psychophysiology. 32 (2): 75–84. doi:10.1027/0269-8803/a000184. ISSN 0269-8803. S2CID 151333609.
- ^ Pennebaker JW (1982). The Psychology of Physical Symptoms. doi:10.1007/978-1-4613-8196-9. ISBN 978-1-4613-8198-3.
- ^ Antony MM, Brown TA, Craske MG, Barlow DH, Mitchell WB, Meadows EA (September 1995). "Accuracy of heartbeat perception in panic disorder, social phobia, and nonanxious subjects". Journal of Anxiety Disorders. 9 (5): 355–371. doi:10.1016/0887-6185(95)00017-i. ISSN 0887-6185.
- ^ Bryant RA (2011-07-15). "Psychological Interventions for Trauma Exposure and PTSD". Post-Traumatic Stress Disorder. John Wiley & Sons, Ltd. pp. 171–202. doi:10.1002/9781119998471.ch5. ISBN 9781119998471.
- ^ Weber DA, Reynolds CR (June 2004). "Clinical perspectives on neurobiological effects of psychological trauma". Neuropsychology Review. 14 (2): 115–129. doi:10.1023/b:nerv.0000028082.13778.14. PMID 15264712. S2CID 24172922.
- ^ Fischer S, Nater UM (October 4, 2014). "Functional somatic syndromes: asking about exclusionary medical conditions results in decreased prevalence and overlap rates". BMC Public Health. 14 1034. doi:10.1186/1471-2458-14-1034. PMC 4286915. PMID 25280494.
- ^ "Somatic Symptom Disorder: What It Is, Symptoms & Treatment". Cleveland Clinic.
- ^ "Somatic symptom disorder - Diagnosis and treatment - Mayo Clinic". www.mayoclinic.org.
- ^ Barsky AJ, Borus JF (June 1, 1999). "Functional somatic syndromes". Annals of Internal Medicine. 130 (11): 910–921. doi:10.7326/0003-4819-130-11-199906010-00016. PMID 10375340.