Skip to main content
    • Aa
    • Aa

A population-based twin study of functional somatic syndromes

  • K. Kato (a1) (a2), P. F. Sullivan (a2) (a3), B. Evengård (a4) (a5) and N. L. Pedersen (a2) (a6)

The mechanisms underlying the co-occurrence of the functional somatic syndromes are largely unknown. No empirical study has explicitly examined how genetic and environmental factors influence the co-morbidity of these syndromes. We aimed to examine how the co-morbidity of functional somatic syndromes is influenced by genetic and environmental factors that are in common to the syndromes.


A total of 31318 twins in the Swedish Twin Registry aged 41–64 years underwent screening interviews via a computer-assisted telephone system from 1998 to 2002. Four functional somatic syndromes (chronic widespread pain, chronic fatigue, irritable bowel syndrome, and recurrent headache) and two psychiatric disorders (major depression and generalized anxiety disorder) were assessed using structured questions based on standard criteria for each illness in a blinded manner.


Multivariate twin analyses revealed that a common pathway model with two latent traits that were shared by the six illnesses fit best to the women's data. One of the two latent traits loaded heavily on the psychiatric disorders, whereas the other trait loaded on all four of the functional somatic syndromes, particularly chronic widespread pain, but not on the psychiatric disorders. All illnesses except the psychiatric disorders were also affected by genetic influences that were specific to each.


The co-occurrence of functional somatic syndromes in women can be best explained by affective and sensory components in common to all these syndromes, as well as by unique influences specific to each of them. The findings clearly suggest a complex view of the multifactorial pathogenesis of these illnesses.

Corresponding author
*Address for correspondence: K. Kato, Ph.D., School of Nursing and Rehabilitation, International University of Health and Welfare at Odawara, 1-2-25 Shiroyama, Odawara, Kanagawa 250-8588, Japan. (Email:
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

LA Aaron , D Buchwald (2001). A review of the evidence for overlap among unexplained clinical conditions. Annals of Internal Medicine 134, 868881.

AJ Barsky , JF Borus (1999). Functional somatic syndromes. Annals of Internal Medicine 130, 910921.

M Camilleri , E Atanasova , PJ Carlson , U Ahmad , HJ Kim , BE Viramontes , S McKinzie , R Urrutia (2002). Serotonin-transporter polymorphism pharmacogenetics in diarrhea-predominant irritable bowel syndrome. Gastroenterology 123, 425432.

DS Ciccone , BH Natelson (2003). Comorbid illness in women with chronic fatigue syndrome: a test of the single syndrome hypothesis. Psychosomatic Medicine 65, 268275.

K Fukuda , SE Straus , I Hickie , MC Sharpe , JG Dobbins , AL Komaroff (1994). The chronic fatigue syndrome: a comprehensive approach to its definition and study. International Chronic Fatigue Syndrome Study Group. Annals of Internal Medicine 121, 953959.

P Henningsen , S Zipfel , W Herzog (2007). Management of functional somatic syndromes. Lancet 369, 946955.

K Kato , PF Sullivan , B Evengard , NL Pedersen (2006 a). Chronic widespread pain and its comorbidities: a population-based study. Archives of Internal Medicine 166, 16491654.

P Lichtenstein , U De Faire , B Floderus , M Svartengren , P Svedberg , NL Pedersen (2002). The Swedish Twin Registry: a unique resource for clinical, epidemiological and genetic studies. Journal of Internal Medicine 252, 184205.

M Narita , N Nishigami , N Narita , K Yamaguti , N Okado , Y Watanabe , H Kuratsune (2003). Association between serotonin transporter gene polymorphism and chronic fatigue syndrome. Biochemical and Biophysical Research Communications 311, 264266.

C Nimnuan , S Rabe-Hesketh , S Wessely , M Hotopf (2001). How many functional somatic syndromes? Journal of Psychosomatic Research 51, 549557.

A Okifuji , DC Turk , DA Marcus (1999). Comparison of generalized and localized hyperalgesia in patients with recurrent headache and fibromyalgia. Psychosomatic Medicine 61, 771780.

DD Price , R Staud , ME Robinson , AP Mauderli , R Cannon , CJ Vierck (2002). Enhanced temporal summation of second pain and its central modulation in fibromyalgia patients. Pain 99, 4959.

S Romans , C Belaise , J Martin , E Morris , A Raffi (2002). Childhood abuse and later medical disorders in women. An epidemiological study. Psychotherapy and Psychosomatics 71, 141150.

R Staud , ML Smitherman (2002). Peripheral and central sensitization in fibromyalgia: pathogenetic role. Current Pain and Headache Reports 6, 259266.

R Staud , CJ Vierck , RL Cannon , AP Mauderli , DD Price (2001). Abnormal sensitization and temporal summation of second pain (wind-up) in patients with fibromyalgia syndrome. Pain 91, 165175.

P Svedberg , S Johansson , MA Wallander , B Hamelin , NL Pedersen (2002). Extra-intestinal manifestations associated with irritable bowel syndrome: a twin study. Alimentary Pharmacology and Therapeutics 16, 975983.

GN Verne , DD Price (2002). Irritable bowel syndrome as a common precipitant of central sensitization. Current Rheumatology Reports 4, 322328.

F Wolfe , HA Smythe , MB Yunus , RM Bennett , C Bombardier , DL Goldenberg , P Tugwell , SM Campbell , M Abeles , P Clark , (1990). The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: report of the Multicenter Criteria Committee. Arthritis and Rheumatism 33, 160172.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Psychological Medicine
  • ISSN: 0033-2917
  • EISSN: 1469-8978
  • URL: /core/journals/psychological-medicine
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Altmetric attention score

Full text views

Total number of HTML views: 3
Total number of PDF views: 38 *
Loading metrics...

Abstract views

Total abstract views: 214 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 26th May 2017. This data will be updated every 24 hours.