The primary goal of the proposed trial is to assess the short- and long-term efficacy of cognitive behavior therapy (CBT) for irritable bowel syndrome using two treatment delivery systems (self administered, therapist administered). Secondary aims seek to specify the conditions under which CBT may (or may not) achieve its effects (moderator questions), why and how these effects are achieved (mediator questions) and at what economic cost. Long term project goals are to develop an effective self-administered behavioral treatment program that can enhance the quality of patient care, improve clinical outcomes, and decrease the economic and personal costs of one of the most prevalent and intractable GI disorders.

Irritable bowel syndrome (IBS) is a chronic, prevalent, often disabling, GI disorder for which there is no reliable and satisfactory medical option for its full range of symptoms (abdominal pain, bowel dysfunction). An accumulating body of evidence indicates that a specific psychosocial treatment called cognitive behavioral therapy (CBT) is associated with significant reductions in IBS symptoms and related difficulties. Despite its apparent efficacy, CBT's clinical effectiveness (i.e., its generalizability, feasibility, cost effectiveness) has not been adequately established due partly to its duration, cost, and limited accessibility. As the "second generation" of IBS treatments undergo development and validation, it has become increasingly clear that efficacy demonstration is a necessary but not sufficient condition of treatment viability. In a pilot study funded under NIDDK's R03 mechanism, we addressed these problems by developing a briefer, largely self administered version of CBT that requires only 4, 1 hr clinic visits. Our RCT data showed that a 10 session version of CBT can be translated into a 4 session version without compromising patient acceptability or short term efficacy. It is unclear whether treatment effects are maintained long term (out to 12 months), due to theoretical change mechanisms (vs. nonspecific factors common across different forms of therapy), are more pronounced among specific subgroups of patients, or, generalize to a large sample of Rome III diagnosed patients treated by different investigative sites. We seek to address these questions by conducting a larger, more definitive, multisite RCT that will recruit from 2 treatment sites 480 patients with moderate to severe IBS and assess their acute and long term response to brief (4 session) CBT, extended (10 session) CBT, or a credible education/support condition. We will use the first year to develop a clinical infrastructure to ensure the success and integrity of the proposed trial. In the short term, a successful trial will lend empirical validation to a self administered version of CBT that retains the efficacy of standard CBT but is more transportable, accessible to patients outside of research protocols, and less costly to deliver. In the long term, we hope to show that a self guided behavioral treatment program is an effective and efficient treatment delivery system that can enhance the quality of patient care, improve clinical outcomes, and decrease the economic and personal costs of one of the most prevalent and intractable GI disorders.

Inclusion Criteria:

• Males or female patients aged 18 to 70 years (inclusive);
• All ethnic groups;
• Meet Rome III criteria for IBS with symptoms of at least moderate severity (at least 2 days per week);
• Ability to understand and provide informed consent;
• With the exception of antibiotics, participant is willing to remain on a stable dose only through the 4-week pretreatment baseline period prior to randomization;
• Participant either not taking medications or if taking medications willing to suspend starting any new medications only during the initial 4-week pretreatment baseline period;
• Participant demonstrates an ability to speak understand and read, English a the sixth grade level or higher;
• Willingness to be randomized to CBT or Support/Education to which s/he has been assigned to to adhere to protocol requirements;
• Participant is willing to attend regularly scheduled therapy session during active phase of the trial;
• Participant is willing to be contacted and scheduled for follow-up assessment at week 12 and 3, 6, 9, and 12 months after the conclusion of acute treatment phase;
• Participant is willing and able to enter symptom information into an assigned portable computer and complete questionnaires through treatment and at regularly scheduled follow ups
• Participant has access to a telephone; and
• Participant is willing and able to provide adequate information for locator purposes.

Exclusion Criteria:

• Evidence of current structural or biochemical abnormalities or medication use that better explain the participant's IBS symptoms (e.g. IBD);
• Evidence of a current infection or infection of any type within the 2 weeks prior to the study gastroenterologists' evaluation which would obscure the presentation of IBS symptoms. In such cases the baseline can be delayed until 2 weeks after complete recovery.
• Participant has received antibiotics (e.g. rifaximin and or neomycin) specifically targeted to treat IBS symptoms within the past 3 months. In this instance eligibility will be suspended for 12 weeks from the initial date the antibiotic was consumed.
• Participant has undergone previous abdominal surgery that would have caused significant alternation of the anatomy/physiology of the digestive/GI tract, which adequately explains GI symptoms;
• Participant has been diagnosed and/or treated for malignancy in the past 5 years with the exception of localized basal or squamous cell carcinomas of the skin;
• Participant has an unstable extraintestinal medical condition whose immediate or foreseeable treatment needs (e.g., hospitalization, conflicting physician visits) would realistically interfere with study demands (e.g., consistent attendance at treatment sessions and/or ability to participate in telephone interventions) or may affect the interpretation of clinical efficacy data;
• Participant has a major psychiatric disorder, which in the opinion of the senior clinical staff may impede conduct of the clinical trial. These disorders include but are not limited to major depression diagnosis with a high risk of suicidal behavior (i.e. intent or plan), alcohol or substance abuse/dependence within the past year, a lifetime history of schizophrenia or schizoaffective disorder or gross cognitive impairments;
• Participant has other conditions which in the opinion of the senior clinical staff would influence negatively the conduct of the clinical trial;
• Participant is currently receiving targeted psychotherapy for IBS and is unwilling or unable to discontinue his/her treatment for the acute treatment phase of this study;
• Participant is unable to complete all scheduled screening visits; and participant is inaccessible for interventions and/or follow-up evaluations.

One of the main goals of the IBSOS is to establish a central repository of data for subsequent hypothesis-based research designed to enable the widest dissemination of data, while also protecting the privacy of the participants and the utility of the data by de-identification and masking of potentially sensitive data elements. To support these objectives we will catalog and provide basic results sets through the NIDDK repository www.niddkrepository.org, as well as create and deliver more comprehensive de-identified data sets, for each completed aim of the IBSOS study. Study data will be provided in SAS/SPSS format and will be named to match corresponding codebooks or dictionary and study forms, which will also be located within the Repository. Codebooks will include variable names and labels, where applicable. For analysis data sets, we will provide documentation for analyses conducted for manuscript publication as well as descriptive summaries for main variables.

Baseline data: September 1, 2018 Primary outcome manuscript: May 1, 2018 Entire dataset from intervention study: September 1, 2019

All applications for access of these data sets must be submitted through an application to NIDDK central repository as outlined on their website www.niddkrepository.org. Access for the data submitted to the NIDDK Data Repository will be determined by the NIDDK. All investigators who receive IBSOS resources must agree to acknowledge the IBSOS Study and the NIDDK central repository.