The prevalence and co-existence of psychosocial factors in functional gastrointestinal disorders and other functional somatic syndromes

Functional Somatic Syndromes (FSS) are health conditions for which no apparent biological cause can be identified. Examples of such conditions include Functional Gastrointestinal Disorders (FGIDs; e.g. Irritable Bowel Syndrome), chronic pain and chronic fatigue. Research has shown strong associations between FGIDs and a number of adverse psychological phenomena. Some doubt has been expressed, however, over the specificity of these relationships to the gastrointestinal (GI) system, with similar findings in other FSSs such as chronic pain. As such, the present study sought to test whether adverse psychological phenomena are equally involved in a range of FSSs, using a cross-sectional correlational design with standardized measures and consistent diagnostic criteria. Participants were recruited from various sites around Sydney at which a high prevalence of FSSs were known to exist: hospital and private Gastroenterology consultation rooms, private and university Chiropractic clinics and the Macquarie University Psychology undergraduate student pool. A total of N = 133 participants were included in the study: n = 58 (43%) met ROME III criteria for FGID diagnosis and n = 79 (59%) met the criteria for an extra-GI diagnosis (outside the gastrointestinal tract, e.g. chronic low back pain and fibromyalgia). The data revealed a strong pattern of similar associations between adverse psychological constructs and the symptom burden of GI and extra-GI symptoms. Somatization (the tendency to manifest physical symptoms through psychological distress) was most strongly and consistently correlated with GI and extra-GI symptoms. In addition, significant comorbidity was found between different FSSs. The current study identifies an analogous role of adverse psychological phenomena in a range of FSSs, suggesting that the influence of psychological phenomena may be manifested in multiple physical expressions, as well as concluding that their presence significantly impacts the symptom burden of GI and extra-GI disorders.