High Somatic Symptom Burdens and Functional Gastrointestinal Disorders

Background & Aims: Unexplained, multi-system somatic symptoms and syndromes, the hallmark features of somatization, are prevalent in patients with functional gastrointestinal disorders (FGIDs). We studied outpatients attending a gastroenterology clinic to see whether current somatic symptom burdens (a somatization state measure) or number of prior functional diagnoses (a somatization trait measure) could predict the presence of an FGID over structural gastrointestinal disease, and whether the predictive value was dependent on comorbid depression or anxiety disorders. Methods: Clinical data from 327 consecutive new referrals to an outpatient gastroenterology practice were reviewed, 187 with an FGID and 140 with a structural illness. Somatization state and trait were measured by using self-reported current symptoms and functional diagnoses recorded in the medical history, respectively. Psychiatric comorbidity (depression or anxiety disorders) was extracted from chart review. Results: FGID subjects endorsed more somatization state symptoms, had more somatization trait diagnoses, and had greater likelihood of psychiatric comorbidity (P < .001 for each). Logistic regression analysis adjusting for age and sex differences showed that each of these features independently predicted the likelihood of an FGID over structural disease (P < .05 for each). When high ratings on the somatization measures were present together with psychiatric comorbidity, the positive predictive value exceeded 0.95. Conclusions: Higher burdens of either current somatic symptoms or functional diagnoses in the medical history are strong predictors of an FGID in outpatients presenting with gastrointestinal complaints. The mechanism is not solely dependent on a relationship with affective disorders, which independently predicts FGID, at least in part, through another path. Background & Aims: Unexplained, multi-system somatic symptoms and syndromes, the hallmark features of somatization, are prevalent in patients with functional gastrointestinal disorders (FGIDs). We studied outpatients attending a gastroenterology clinic to see whether current somatic symptom burdens (a somatization state measure) or number of prior functional diagnoses (a somatization trait measure) could predict the presence of an FGID over structural gastrointestinal disease, and whether the predictive value was dependent on comorbid depression or anxiety disorders. Methods: Clinical data from 327 consecutive new referrals to an outpatient gastroenterology practice were reviewed, 187 with an FGID and 140 with a structural illness. Somatization state and trait were measured by using self-reported current symptoms and functional diagnoses recorded in the medical history, respectively. Psychiatric comorbidity (depression or anxiety disorders) was extracted from chart review. Results: FGID subjects endorsed more somatization state symptoms, had more somatization trait diagnoses, and had greater likelihood of psychiatric comorbidity (P < .001 for each). Logistic regression analysis adjusting for age and sex differences showed that each of these features independently predicted the likelihood of an FGID over structural disease (P < .05 for each). When high ratings on the somatization measures were present together with psychiatric comorbidity, the positive predictive value exceeded 0.95. Conclusions: Higher burdens of either current somatic symptoms or functional diagnoses in the medical history are strong predictors of an FGID in outpatients presenting with gastrointestinal complaints. The mechanism is not solely dependent on a relationship with affective disorders, which independently predicts FGID, at least in part, through another path. See Vandenberghe J et al on page 1684 for companion article in the May 2007 issue of Gastroenterology. See Vandenberghe J et al on page 1684 for companion article in the May 2007 issue of Gastroenterology. Interest is growing in symptoms from nongastrointestinal sites that are present in patients with functional gastrointestinal disorders (FGIDs). Somatic symptoms and syndromes across several organ systems and unexplained by physical illness are reported by at least one fourth of patients,1North C.S. Downs D. Clouse R.E. et al.The presentation of irritable bowel syndrome in the context of somatization disorder.Clin Gastroenterol Hepatol. 2004; 2: 787-795Abstract Full Text Full Text PDF PubMed Scopus (81) Google Scholar a phenomenon called somatization.2Clouse R.E. Lustman P.J. Use of psychopharmacological agents for functional gastrointestinal disorders.Gut. 2005; 54: 1332-1341Crossref PubMed Scopus (70) Google Scholar The biologic underpinnings of somatization remain unknown; its presence and degree are determined crudely by the clinical expression of medically unexplained symptoms. Because the FGIDs also lack a defined physical basis, it is possible that they represent a component of the somatization process, or at least that the neurophysiologic mechanisms underlying somatization have a relevant role in the development or presentation of FGIDs.2Clouse R.E. Lustman P.J. Use of psychopharmacological agents for functional gastrointestinal disorders.Gut. 2005; 54: 1332-1341Crossref PubMed Scopus (70) Google Scholar For research purposes, somatization has been operationalized in several fashions.3Kirmayer L.J. Robbins J.M. Three forms of somatization in primary care: prevalence, co-occurrence, and sociodemographic characteristics.J Nerv Ment Dis. 1991; 179: 647-655Crossref PubMed Scopus (333) Google Scholar, 4Simon G.E. Von Korff M. Somatization and psychiatric disorder in the NIMH Epidemiologic Catchment Area study.Am J Psychiatry. 1991; 148: 1494-1500PubMed Google Scholar, 5Lipowski Z.J. Somatization: the experience and communication of psychological distress as somatic symptoms.Psychother Psychosom. 1987; 47: 160-167Crossref PubMed Scopus (104) Google Scholar, 6Kellner R. Somatization: theories and research.J Nerv Ment Dis. 1990; 178: 150-160Crossref PubMed Scopus (145) Google Scholar, 7Katon W. Lin E. Von Korff M. et al.Somatization: a spectrum of severity.Am J Psychiatry. 1991; 148: 34-40PubMed Google Scholar, 8Diagnostic and statistical manual of mental disorders. 4th rev ed. American Psychiatric Association, Washington, DC2000Google Scholar Measures can reflect the somatization state, an expression of recent medically unexplained symptoms, or the somatization trait, a background of remote functional syndromes provided by the medical history. Some evidence exists that over-reporting of current symptoms provides a method of predicting FGID over structural gastrointestinal disease, supporting the importance of the somatization state.9Brown W.H. Chey W.D. Elta G.H. Number of responses on a review of systems questionnaire predicts the diagnosis of functional gastrointestinal disorders.J Clin Gastroenterol. 2003; 36: 222-227Crossref PubMed Scopus (14) Google Scholar, 10Wise J.L. Locke G.R. Zinsmeister A.R. et al.Risk factors for non-cardiac chest pain in the community.Aliment Pharmacol Ther. 2005; 22: 1023-1031Crossref PubMed Scopus (17) Google Scholar There also is evidence that an increased burden of functional syndromes in the medical history helps define the FGID patient.11Whitehead W.E. Palsson O. Jones K.R. Systematic review of the comorbidity of irritable bowel syndrome with other disorders: what are the causes and implications?.Gastroenterology. 2002; 122: 1140-1156Abstract Full Text Full Text PDF PubMed Scopus (915) Google Scholar, 12Locke 3rd, G.R. Zinsmeister A.R. Fett S.L. et al.Overlap of gastrointestinal symptom complexes in a US community.Neurogastroenterol Motil. 2005; 17: 29-34Crossref PubMed Scopus (223) Google Scholar Thus, somatization state and trait features both might be pertinent to FGID pathophysiology. Whether these characteristics are fully interrelated or whether each bears independent relevance has not been explored. Addressing such concerns would help determine the relative importance of short-term and long-term processes on FGID expression. Depression and anxiety disorders also are comorbid conditions in patients with FGID, diagnosed at presentation or in the past in as much as 60%–70% of patients with irritable bowel syndrome (IBS), for example.1North C.S. Downs D. Clouse R.E. et al.The presentation of irritable bowel syndrome in the context of somatization disorder.Clin Gastroenterol Hepatol. 2004; 2: 787-795Abstract Full Text Full Text PDF PubMed Scopus (81) Google Scholar, 13Schwarz S.P. Blanchard E.B. Berreman C.F. et al.Psychological aspects of irritable bowel syndrome: comparisons with inflammatory bowel disease and nonpatient controls.Behav Res Ther. 1993; 31: 297-304Crossref PubMed Scopus (62) Google Scholar, 14Clouse R.E. Alpers D.H. The relationship of psychiatric disorder to gastrointestinal illness.Annu Rev Med. 1986; 37: 283-295Crossref PubMed Scopus (29) Google Scholar, 15Miller A.R. North C.S. Clouse R.E. et al.The association of irritable bowel syndrome and somatization disorder.Ann Clin Psychiatry. 2001; 13: 25-30Crossref PubMed Google Scholar, 16Walker E.A. Roy-Byrne P.P. Katon W.J. et al.Psychiatric illness and irritable bowel syndrome: a comparison with inflammatory bowel disease.Am J Psychiatry. 1990; 147: 1656-1661PubMed Google Scholar, 17Masand P.S. Kaplan D.S. Gupta S. et al.Major depression and irritable bowel syndrome: is there a relationship?.J Clin Psychiatry. 1995; 56: 363-367PubMed Google Scholar, 18Blanchard E.B. Scharff L. Schwarz S.P. et al.The role of anxiety and depression in the irritable bowel syndrome.Behav Res Ther. 1990; 28: 401-405Crossref PubMed Scopus (146) Google Scholar The significance of the association remains uncertain; the strongest observation against a direct relationship is the dissociated response of FGID symptoms from change in psychometric scale scores with successful treatment of the gastrointestinal symptoms.19Jackson J.L. O’Malley P.G. Tomkins G. et al.Treatment of functional gastrointestinal disorders with antidepressant medications: a meta-analysis.Am J Med. 2000; 108: 65-72Abstract Full Text Full Text PDF PubMed Scopus (482) Google Scholar, 20Drossman D.A. Toner B.B. Whitehead W.E. et al.Cognitive-behavioral therapy versus education and desipramine versus placebo for moderate to severe functional bowel disorders.Gastroenterology. 2003; 125: 19-31Abstract Full Text Full Text PDF PubMed Scopus (574) Google Scholar, 21Clouse R.E. Lustman P.J. Eckert T.C. et al.Low-dose trazodone for symptomatic patients with esophageal contraction abnormalities: a double-blind, placebo-controlled trial.Gastroenterology. 1987; 92: 1027-1036Abstract Full Text PDF PubMed Scopus (306) Google Scholar Somatization might serve as a mediator of the relationship between FGID and psychiatric comordibity, considering the commingling of anxiety and depression with advanced degrees of somatization observed in small samples of IBS patients.15Miller A.R. North C.S. Clouse R.E. et al.The association of irritable bowel syndrome and somatization disorder.Ann Clin Psychiatry. 2001; 13: 25-30Crossref PubMed Google Scholar Whether somatization state features or trait features have greater bearing on this relationship is yet to be examined. We hypothesized that high somatic symptom counts and histories of abundant prior functional diagnoses would each independently predict the diagnosis of an FGID over a structural gastrointestinal disease in an outpatient population after controlling for potentially confounding factors, supporting the importance of both recent and chronic somatization toward susceptibility to FGIDs. We also hypothesized that comorbid psychiatric illness (depression or anxiety disorder) would not have independent predictive value toward an FGID diagnosis once the contributions from the somatization measures were taken into account. Thus, the previously observed relationship of psychiatric illness with FGID primarily would relate to its relationship with somatization. A retrospective review of chart data from a university-based practice was used to test these hypotheses. Consecutive patients identified from billing records, seen in an outpatient university-based adult gastroenterology practice either initially or in follow-up during a 2-year period from January 1, 2003–January 1, 2005 and followed for at least 3 months, provided the primary subject pool. Subjects were stratified into 3 groups on the basis of chart notations made by the treating physician: (1) an FGID group, in which a functional disorder had been considered responsible for the presenting symptoms; (2) a structural gastrointestinal disease group, in which a structural illness had been established and had been considered sufficient to explain the presenting symptoms; and (3) a group in which a structural illness had been identified but was considered insufficient to explain symptoms, according to the chart notations. The last group was excluded from the primary analyses. FGIDs are diagnosed in this outpatient office according to a criteria-based system (Rome II),22Drossman D. Thompson W. Whitehead W. et al.Rome II: functional gastrointestinal disorders. Degnon Assoc, Inc, McLean, VA2000Google Scholar and the 3-month follow-up requirement was imposed to ensure stability of the functional or structural diagnosis. Review of clinical records for the purposes of this study was approved by the Washington University Human Studies Committee before study conception. Clinical features, including demographic characteristics and the diagnosis to which symptoms were attributed, were systematically extracted from the outpatient record by using an instrument prepared a priori for data extraction. All clinical notations, including records from office visits, telephone contacts, or written communications, were considered potential sources of clinical data. Although the investigators performing the record reviews were not blinded to subject diagnosis, they were unaware of the study hypotheses being tested. Two measures of somatization were extracted. Each subject had completed a self-reported review-of-systems checklist at the initial visit. This checklist is composed of 60 symptoms across 10 organ systems, and subjects had been asked to endorse only those symptoms that were “currently” experienced. Total numbers of endorsed symptoms and systems were recorded, as were responses to a subset of 13 symptoms that represented 13 of 15 symptoms included in a previously validated measure of somatic symptom severity (Table 1).23Kroenke K. Spitzer R.L. Williams J.B. The PHQ-15: validity of a new measure for evaluating the severity of somatic symptoms.Psychosom Med. 2002; 64: 258-266PubMed Google Scholar A high degree of somatization state was considered present for descriptive purposes in characterizing subject group if endorsement was at or above the median (≥6 symptoms). A second measure assessed somatization trait as the sum of all documented patient-reported or physician-determined gastrointestinal and nongastrointestinal functional disorders (symptoms or syndromes that were unexplained medically) that had been recorded in the history (eg, fibromyalgia, chronic headache). For descriptive purposes, a high degree of somatization trait was considered present if, in addition to the primary FGID, ≥2 functional disorders had been established in that individual. This threshold corresponded to the median value in a previously reported group of FGID patients who had been deemed candidates for antidepressant therapy.24Sayuk G.S. Elwing J.E. Lustman P.J. et al.Predictors of premature antidepressant discontinuation in functional gastrointestinal disorders (FGIDs): a survival analysis approach.Gastroenterology. 2006; 130: A-26PubMed Google ScholarTable 1Symptoms Included in the Somatization State MeasureaExcludes sexual symptoms included in the PHQ-15.General Lack of energy/fatigueCardiovascular Chest pain Heart palpitations Shortness of breathMusculoskeletal Back pain Joint pain/muscle acheGastrointestinal Belching/bloating/nausea Changes in stool form Stomach painNeurologic Dizziness Fainting HeadachePsychiatric Difficulty sleepingModified from Kroenke et al.45Kroenke K. Physical symptom disorder: a simpler diagnostic category for somatization-spectrum conditions.J Psychosom Res. 2006; 60: 335-339Abstract Full Text Full Text PDF PubMed Scopus (119) Google Scholara Excludes sexual symptoms included in the PHQ-15. Open table in a new tab Modified from Kroenke et al.45Kroenke K. Physical symptom disorder: a simpler diagnostic category for somatization-spectrum conditions.J Psychosom Res. 2006; 60: 335-339Abstract Full Text Full Text PDF PubMed Scopus (119) Google Scholar Psychiatric comorbidity was considered present when a diagnosis of depression or an anxiety disorder was available in the medical record, having been made in the past or coexistent with the gastrointestinal disorder. Psychiatric diagnoses are made in this outpatient office by using criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders, Version IV,8Diagnostic and statistical manual of mental disorders. 4th rev ed. American Psychiatric Association, Washington, DC2000Google Scholar but a specific interview or instrument is not used. Patient-reported diagnoses of depression or an anxiety disorder also were accepted as evidence of psychiatric illness. Only depression and anxiety disorders were included because together these constitute the most common psychiatric diagnoses encountered in patients with FGID.11Whitehead W.E. Palsson O. Jones K.R. Systematic review of the comorbidity of irritable bowel syndrome with other disorders: what are the causes and implications?.Gastroenterology. 2002; 122: 1140-1156Abstract Full Text Full Text PDF PubMed Scopus (915) Google Scholar, 25Lydiard R.B. Fossey M.D. Marsh W. et al.Prevalence of psychiatric disorders in patients with irritable bowel syndrome.Psychosomatics. 1993; 34: 229-234Abstract Full Text PDF PubMed Scopus (192) Google Scholar Measures of central tendency are reported as mean ± standard error of the mean for continuous variables and median values with ranges for categorical data. Group data were compared by using Student t tests for continuous data and χ2 tests for binomial data. The overlapping of somatization state, somatization trait, and psychiatric illness was explored through the calculation of Pearson correlation coefficients and the generation of Venn diagrams. Positive predictive values were calculated as the proportion of true positives over the sum of true positives plus false positives. Logistic regression modeling without elimination was used to evaluate predictors of FGID over structural gastrointestinal disease. The somatization measures were used as continuous variables in the models. Statistical analyses were conducted by using SPSS v14.0 (SPSS Inc, Chicago, IL), with a P value <.05 as a determinant of statistical significance in two-tailed testing. A total of 524 potential subjects were identified during the 2-year study period, 127 of whom had either incomplete or unretrievable records (n = 32) or had not been followed for 3 months (n = 95). Of the remaining 397 subjects, 70 fell into the third subject group, had presenting symptoms that were not fully explained by the identified structural gastrointestinal disease, and were not considered in the primary analyses. The 327 other subjects had a mean of 44.9 ± 0.9 months of clinical follow-up available for chart review. A summary of baseline demographic characteristics is provided in Table 2.Table 2Demographic Characteristics of the SubjectsCharacteristicAll subjects (n = 327)Subjects with FGID (n = 187)Subjects with a structural gastrointestinal disease (n = 140)P valueaComparing subjects with FGID with those with structural gastrointestinal disease.Age, mean ± SEM (y)46.1 ± 0.845.6 ± 1.245.3 ± 1.6.9Sex, n (%) Female198 (60.6)131 (70.1)67 (47.9)<.001 Male129 (39.4)56 (29.9)73 (52.1)Race, n (%) Non-white6 (1.8)4 (2.1)2 (1.4).7 White321 (98.2)183 (97.9)138 (98.6)a Comparing subjects with FGID with those with structural gastrointestinal disease. Open table in a new tab FGID had been diagnosed in 187 subjects (57.2%), the most common of which was IBS (n = 49, 26.2% of the FGID subjects). Functional esophageal disorders had been identified in 25 (13.3%; chest pain, n = 9; dysphagia, n = 10, other functional esophageal disorders, n = 6), functional gastroduodenal disorders in 60 (32.0%; functional dyspepsia, n = 19; functional vomiting disorders, n = 39; other functional gastroduodenal disorders, n = 2), and non-IBS functional bowel disorders in an additional 53 (28.3%; functional abdominal pain, n = 23; functional constipation, n = 10; functional diarrhea, n = 7; functional bloating, n = 4; other functional bowel disorders, n = 9). The FGID group had a significantly higher proportion of female subjects than the group with structural gastrointestinal disease (Table 2). Symptoms had been attributed to a structural gastrointestinal disease in 140 subjects (42.8%). Gastroesophageal reflux disease was the most common diagnosis in this group, being identified in 42 subjects (30.0% of all structural diagnoses). Additional prevalent diagnoses included ulcerative colitis (n = 35, 25.0%), achalasia (n = 20, 14.3%), and Crohn’s disease (n = 14, 10.0%). Twenty-nine subjects (20.7%) had a variety of other gastrointestinal diseases. Subjects with FGID were significantly more likely than their structural disease counterparts to have a high degree of somatization state, a high degree of somatization trait, and psychiatric comorbidity (Figure 1). With regard to current somatic symptoms at the time of presentation, subjects with FGID had endorsed more symptoms over more systems on the review-of-systems checklist and almost twice as many specific somatic symptoms on the somatization state measure than subjects with structural gastrointestinal disease (Table 3). More functional disorders, other than the primary diagnosis, used in the somatization trait measure also were found in the histories of patients with FGID (Table 3). The most common of these additional disorders are listed in Table 3. Greater proportions of subjects in the FGID group had been given diagnoses of both depression and anxiety disorders than subjects with structural gastrointestinal disease (23.5% vs 6.4% and 20.3% vs 7.1%, respectively; P ≤ .001 for each comparison).Table 3Summary of Somatization FeaturesMeasureAll subjects (n = 327)Subjects with FGID (n = 187)Subjects with structural gastrointestinal disease (n = 140)P valueaComparing subjects with FGID with those with structural gastrointestinal disease.Review-of-systems checklist No. of systems endorsed,bOut of a total of 10 possible systems. mean ± SEM3.9 ± 0.24.6 ± 0.23.1 ± 0.2<.001 No. of current symptoms,cOut of a total of 60 possible symptoms. mean ± SEM9.2 ± 0.411.2 ± 0.66.5 ± 0.5<.001 Somatization state measure symptoms,dOut of a total of 13 possible symptoms. mean ± SEM3.4 ± 0.14.3 ± 0.22.3 ± 0.2<.001Medical history review Prevalence of nongastrointestinal functional disorders,eIn descending order; those with <10 total subjects not listed. n (%) Chronic headache61 (18.7)48 (25.7)13 (9.3)<.001 Back pain36 (11.0)24 (12.8)12 (8.6).15 Somatosensory disturbance36 (11.0)31 (16.6)5 (3.6)<.001 Chronic pelvic pain11 (3.4)10 (5.3)1 (0.7).02 Fibromyalgia8 (2.4)7 (3.7)1 (0.7).08 No. of somatization trait disorders, mean ± SEM1.7 ± 0.12.6 ± 0.10.5 ± 0.1<.001a Comparing subjects with FGID with those with structural gastrointestinal disease.b Out of a total of 10 possible systems.c Out of a total of 60 possible symptoms.d Out of a total of 13 possible symptoms.e In descending order; those with <10 total subjects not listed. Open table in a new tab The relationships between somatization state, somatization trait, and psychiatric comorbidity for each subject group are shown in Figure 2. In both groups the somatization state and trait measures were modestly but significantly correlated (r = 0.44 and r = 0.41, respectively; P < .001 for each). Within the FGID group, the presence of a psychiatric diagnosis portended a higher scale score on the somatization state measure (5.2 ± 0.3 vs 2.8 ± 0.1, P = .01) and was associated with a greater number of functional disorders on the somatization trait measure (3.5 ± 0.2 vs 1.1 ± 0.1, P < .001). There were no differences in somatization scale scores by psychiatric comorbidity status in the group with structural gastrointestinal disease. The greater degree of commingling of all 3 features within the FGID group is apparent from review of Figure 2. Results from logistic regression modeling of clinical and demographic predictors of FGID are summarized in Table 4. Female sex, psychiatric comorbidity, and greater scores on the somatization measures each independently predicted the presence of an FGID over a structural gastrointestinal disease. When the same analysis was conducted including within the FGID group the 70 initially excluded subjects who had symptoms out of proportion to a structural gastrointestinal disease (ie, suspected functional symptoms concurrent with the structural disease), the identical predictors were identified (female sex: odds ratio [OR], 2.43; 95% confidence interval [CI], 1.51–3.90; psychiatric comorbidity: OR, 2.34; 95% CI, 1.24–4.42; somatization state symptoms: OR, 1.30; 95% CI, 1.15–1.48; somatization trait disorders: OR, 1.37; 95% CI, 1.02–1.83).Table 4Predictors of the Presence of FGID in This Outpatient PracticePredictorOR95% CIP valueAge1.000.98–1.01.8Female sex2.451.47–4.08.001Psychiatric comorbidityaPresence of a diagnosis of depression or an anxiety disorder.2.471.27–4.80.01Somatization state symptomsbMeasure used as a continuous variable.1.271.11–1.46.001Somatization trait disordersbMeasure used as a continuous variable.1.411.05–1.91.02a Presence of a diagnosis of depression or an anxiety disorder.b Measure used as a continuous variable. Open table in a new tab The cumulative contribution of psychiatric comorbidity and high degrees of somatization state and trait on the predictive value of an FGID was examined for each sex and for the whole subject group (Figure 3). With an increasing number of features, the likelihood of diagnosing an FGID increased linearly. Whereas subjects without psychiatric comorbidity and with low degrees of somatization had less than 50% likelihood of having an FGID, nearly 90% of subjects with any 2 features had an FGID, and more than 95% of subjects with all 3 features ultimately were diagnosed as having an FGID to explain the presenting symptoms. In this study we found an increase in the number of current somatic symptoms and previous functional disorders in outpatients with FGID at a university-based practice when compared with those having structural gastrointestinal diseases. As expected, psychiatric comorbidity (depression and anxiety disorders) also was more prevalent in the former subject group. In support of our hypotheses, each somatization measure independently predicted the presence of an FGID. The relationship of psychiatric comorbidity to FGID, however, was not completely mediated by somatization, because psychiatric comorbidity was retained as an independent predictor in the regression analysis. The same outcomes were found when subjects with symptoms out of proportion to structural disease were included. Thus, high current somatic symptom burdens, abundant past functional disorders, and psychiatric comorbidity each helped identify patients with functional gastrointestinal symptoms, whether structural gastrointestinal disease was present or not. The predictive value was pronounced in this outpatient population; the patient with high ratings on both somatization scales as well as a history of depression or an anxiety disorder had >95% likelihood of having an FGID. Nongastrointestinal somatic symptoms and syndromes, usually also functional in origin, have long been observed in patients with FGID.11Whitehead W.E. Palsson O. Jones K.R. Systematic review of the comorbidity of irritable bowel syndrome with other disorders: what are the causes and implications?.Gastroenterology. 2002; 122: 1140-1156Abstract Full Text Full Text PDF PubMed Scopus (915) Google Scholar For example, fibromyalgia is diagnosed in as many as two thirds of patients with IBS.11Whitehead W.E. Palsson O. Jones K.R. Systematic review of the comorbidity of irritable bowel syndrome with other disorders: what are the causes and implications?.Gastroenterology. 2002; 122: 1140-1156Abstract Full Text Full Text PDF PubMed Scopus (915) Google Scholar, 26Sperber A.D. Carmel S. Atzmon Y. et al.Use of the Functional Bowel Disorder Severity Index (FBDSI) in a study of patients with the irritable bowel syndrome and fibromyalgia.Am J Gastroenterol. 2000; 95: 995-998Crossref PubMed Google Scholar, 27Sperber A.D. Atzmon Y. Neumann L. et al.Fibromyalgia in the irritable bowel syndrome: studies of prevalence and clinical implications.Am J Gastroenterol. 1999; 94: 3541-3546Crossref PubMed Google Scholar, 28Barton A. Pal B. Whorwell P.J. et al.Increased prevalence of sicca complex and fibromyalgia in patients with irritable bowel syndrome.Am J Gastroenterol. 1999; 94: 1898-1901Crossref PubMed Scopus (61) Google Scholar, 29Veale D. Kavanagh G. Fielding J.F. et al.Primary fibromyalgia and the irritable bowel syndrome: different expressions of a common pathogenetic process.Br J Rheumatol. 1991; 30: 220-222Crossref PubMed Scopus (179) Google Scholar Similar data exist for chronic fatigue syndrome, temporomandibular joint disorder,30Jones K.R. Palsoon