OBJECTIVES: Patients with several painful functional gastrointestinal disorders (FGIDs) are reported to have a high prevalence of psychosocial disturbance. These aspects have not been studied extensively in patients with suspected Sphincter of Oddi dysfunction (SOD). METHODS: A total of 214 patients with post-cholecystectomy pain and suspected SOD were enrolled in seven US centers in a multicenter-randomized trial (Evaluating Predictors and Interventions in Sphincter of Oddi Dysfunction). Baseline assessments included pain descriptors and burden, structured psychosocial assessments of anxiety/depression, coping, trauma, and health-related quality of life. Patients with high levels of depression, suicidal ideation, or psychosis were excluded. RESULTS: The study population (92% female, mean age 38) reported anxiety (9%), depression (8%), past sexual trauma (18%), and physical abuse (10%). Of the total screened population (n=1460), 3.9% of the patients were excluded because of the presence of defined severe psychological problems. The mean medical outcomes study short-form-36 (SF-36) physical and mental composite scores were 38.70 (s.d.=7.89) and 48.74 (s.d.=9.60), respectively. Most subjects reported symptoms of other FGIDs. There were no correlations between the extent of the pain burden in the 3 months before enrollment and the baseline anxiety scores or victimization history. However, those with greater pain burden were significantly more depressed. There were no meaningful differences in the psychosocial parameters in subjects with or without irritable bowel, and those who had cholecystectomy for stones or functional gallbladder disease. Those declining randomization were comparable to those randomized. CONCLUSIONS: Psychosocial comorbidity in SOD is high. However, it does not appear to differ significantly from that reported in surveys of age-and gender-matched general populations, and may be lower than reported with other FGIDs.