Irritable Bowel Syndrome (IBS)NCT06940596
Exclude or Expose in Irritable Bowel Syndrome: What Works for Whom and How?
A study testing FODMAP Diet and Exposure-based Cognitive Behavioral Therapy in people with Irritable Bowel Syndrome (IBS) and Intestinal Diseases, run by University of Melbourne at 1 site in Australia.
Trial summary
This research project will assess how two treatments for irritable bowel syndrome (one dietary and one behavioral) work and for whom. This will be done by assessing moderators (what treatment works for who and in what context) and mediators (how treatment works). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Irritable Bowel Syndrome (IBS), Intestinal Diseases, Gastrointestinal Disease
- What is being tested?
- FODMAP Diet and Exposure-based Cognitive Behavioral Therapy
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 235 participants
- Where
- 1 siteAustralia
- Study dates
- 22 May 2025to Apr 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Inclusion Criteria: Each participant must meet all of the following criteria to be enrolled in this trial:
- Living in Australia or the United States
- Aged 18 years or older
- Body Mass Index (BMI) [Equation]18.5kg/m2 and [Equation] 34.9kg/m2
- Diagnosed with IBS by a General Practitioner, Family Physician, or Gastroenterologist, or Advanced Specialist Dietitian
- Currently fulfill Rome IV criteria for IBS
- Symptomatic at the time of recruitment (IBS-SSS > 175)
- Access to a computer and internet
- Sufficient English language and computer skills to complete a text-based online treatment
- Willing to make dietary or behavioral changes in line with the allocated treatment program
- Ability to provide informed consent
Exclusion Criteria:Patients meeting any of the following criteria will be excluded from the trial:
- Presence or known history of other GI disease (e.g. coeliac disease, Inflammatory Bowel Disease) or history of gastrointestinal cancer
- History of major gastrointestinal surgery (not appendectomy, cholecystectomy or hemorrhoidectomy)
- Individuals who report alarm symptoms (e.g., blood in stool, recent unexplained/unintentional weight loss >5% body weight, a recent change in bowel habits if >50 years, family history of gastrointestinal cancer or gastrointestinal diseases, large volumes of diarrhea occurring at night, fever associated with gut symptoms, recurrent vomiting, persistent unexplained iron deficiency) will be excluded if appropriate medical investigations have not been conducted, unless written medical approval is provided from a general practitioner, family physical, or gastroenterologist.
- Diagnosis of major disease that could explain current gastrointestinal symptoms such as severe diabetic, cardiac, liver, neurological, neuropathy disease
- History or current diagnosis of psychotic disorder or bipolar disorder
- Current diagnosis of substance abuse disorder or major depressive disorder or active suicidal ideation
- History or current diagnosis of an eating disorder
- Current enteral/parenteral feeding or use of supplemental feeds (e.g. Ensure)
- Pregnant or lactating or planning to become pregnant during the 12-week intervention period
- Commenced or change in dose of antibiotics and medications that potentially affect the gastrointestinal transit (e.g. anti-diarrheals and laxatives) in the 3 months preceding study commencement.
- Commenced taking or changed dose of probiotics, prebiotics, fibre supplements and digestive enzymes in the 3 months preceding study commencement
- Commenced or change dose in psychotropic medication in the 3 months preceding study commencement
- Are currently undertaking behavioral therapy for IBS (including cognitive behavioral therapy, CBT), or have undertaken clinician-delivered behavioral therapy for the treatment of IBS
- Are currently undertaking or have undertaken a dietitian-prescribed and delivered restrictive diet for IBS (e.g., FODMAP diet).
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Jacqueline L Anderson, APD contact
Australia1 site, 1 recruiting
- Recruiting
University of Melbourne
Melbourne, Victoria, 3010
Jessica Biesiekierski
About this study
Official title: Exclude or Expose in Irritable Bowel Syndrome: What Works for Whom, and How? A Randomized Controlled Trial of Internet-Delivered FODMAP Diet Versus Exposure-Based Cognitive Behavioral Therapy
This research project will assess how two treatments for irritable bowel syndrome (one dietary and one behavioral) work and for whom. This will be done by assessing moderators (what treatment works for who and in what context) and mediators (how treatment works). Investigators will also assess how the diet and behavioral treatments affect IBS symptoms during treatment. Participants will be randomized to either: i. A FODMAP diet online program that focuses on modifying the consumption of foods high or moderate in fermentable carbohydrates (FODMAPS) to manage IBS symptoms. or, ii. An Exposure-based Cognitive Behavioral Therapy (E-CBT) online program for IBS that focuses on changing symptom-related behaviors which are known to worsen IBS symptoms.
Read the detailed description
This research uses a randomized controlled trial to investigate the treatment of irritable bowel syndrome (IBS). A range of treatments for IBS are available, but each work for only a portion of patients, and it is unclear why. This research project will assess how two treatments (one dietary and one behavioral) work and for whom. Investigators will do this by assessing moderators (what treatment works for who and in what context) and mediators (how treatment works). This project will also assess how the diet and behavioral treatments affect IBS symptoms during treatment. Participants will be randomized to either: i. A FODMAP diet online program that focuses on modifying the consumption of foods high or moderate in fermentable carbohydrates (FODMAPS) to manage IBS symptoms. This treatment involves 3-phases: FODMAP restriction (phase 1), FODMAP re-introduction (phase 2), and FODMAP personalization (phase 3), or, ii. An Exposure-based Cognitive Behavioral Therapy (E-CBT) online program for IBS that focuses on symptom-related behaviors such as avoidance of activities and foods, excessive toilet visits, and behaviors to control symptoms which are known to worsen IBS symptoms. E-CBT uses daily self-observation and exposure exercises to change these behaviors to relieve IBS symptoms. Investigators believe that both treatments, FODMAP diet and E-CBT, will lead to an improvement in IBS gastrointestinal symptoms. Primary moderators and mediators to be assessed include gastrointestinal symptom anxiety, food avoidance behaviour and FODMAP intake.
- Being tested
- FODMAP Diet, Exposure-based Cognitive Behavioral Therapy
- Keywords
- Irritable Bowel Syndrome, FODMAP Diet, Behavior Therapy, Gastrointestinal Diseases, Cognitive Behavioral Therapy, Exposure Based Cognitive Behavioral Therapy, Intestinal Diseases, Digestive System Diseases, Low FODMAP Diet
- Medical subject headings
- Irritable Bowel Syndrome, Intestinal Diseases, Gastrointestinal Diseases, Digestive System Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
FODMAP DietOther
The intervention is an online diet program. The diet is the low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet. It is a 3-phase diet which involves: 1.Phase 1 FODMAP restriction: restrict foods high or moderate in FODMAPs and swap these for low FODMAP alternatives; 2. Phase 2 FODMAP reintroduction: continue to follow a low FODMAP diet and complete a series of food challenges to understand which foods and FODMAPs are tolerated and which trigger symptoms; 3. Phase 3 FODMAP personalization: include well-tolerated foods and FODMAPs back into the diet, and restrict poorly tolerated foods and FODMAPs to a level needed to maintain symptom relief. The online FODMAP program is a self-directed diet program with support from an online clinician (Accredited Practicing Dietitian [APD]). The content is delivered over 12 weeks. After each module participants will complete homework activities and questions and submit them to the dietitian for feedback.
Exposure-based Cognitive Behavioral TherapyBehavioural
The intervention is an online behavioral therapy program. The behavioral therapy is Exposure-based Cognitive Behavioral Therapy (E-CBT) Program. The E-CBT program is organised into six steps to be completed over 12 weekly modules with support from an online clinician (Psychologist). The first step contains a rationale for the treatment and instructions on self-observation. Steps 2, 3 and 4 contain a presentation of a psychological model of IBS and continued self-observation exercises. The fifth step covers exposure exercises, divided into three categories; (1) exercises that provoke symptoms, (2) abolishment of behaviors that serve to control symptoms, (3) exposure to situations where symptoms were unwanted. The final step (Step 6) includes how to handle relapses into avoidance behaviors and how to maintain a widened behavioral repertoire. After each module participants will be directed to complete homework activities and questions and submit them to the psychologist for feedback.
| Study group | Role | What they receive |
|---|---|---|
| FODMAP Diet | Experimental | Fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) Diet is a 12-week online intervention with dietitian support. Receives: Other: FODMAP Diet |
| Exposure-based Cognitive Behavioral Therapy (E-CBT) | Experimental | Exposure-based Cognitive Behavioral Therapy is a 12-week online intervention with psychologist support. Receives: Behavioral: Exposure-based Cognitive Behavioral Therapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome (GSRS-IBS )
The GSRS-IBS is a 13-item measure of IBS symptom severity to reflect the last 7 days. The items are scored between 1 (no discomfort at all) and 7 (very severe discomfort), rendering a total score between 13 and 91.
Measured: Measured weekly between baseline (prior to intervention) and after intervention completed (week 12).
Secondary outcomes (26)
Change from baseline in Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome (GSRS-IBS)
The GSRS-IBS is a 13-item measure of IBS symptom severity to reflect the last 7 days. The items are scored between 1 (no discomfort at all) and 7 (very severe discomfort), rendering a total score between 13 and 91.
Measured: Baseline and 3-and 6 month follow up time points after intervention completed (week 12).
Change from baseline in Irritable Bowel Syndrome - Symptom Severity Score (IBS-SSS) questionnaire
The IBS-SSS is a 5-item measure of the severity of IBS symptoms: frequency and severity of abdominal pain, severity of bloating, dissatisfaction with bowel habits and impact on life in general. Questions ask about IBS and gut symptoms during the past 7 days except question 4 which asks participants to enter the number of days they get pain in every 10. days. A total score ranging from 0 to 500. Mild, moderate and severe cases are indicated by scores of 75 to <175, 175 to <300 and >300 respectively
Measured: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in IBS quality of life (IBS-QOL) questionnaire
IBS-QOL is used to assess the impact on quality of life for patients with IBS and consists of 34 items scored between 1 and 5, resulting in a maximum score of 170.
Measured: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Nine Item ARFID (Avoidant Restrictive Food Intake Disorder) Screen (NIAS) questionnaire
NIAS is a 9-item measure of ARFID symptoms. The scale has 9 questions, scored from 0 (strongly disagree) to 5 (strongly agree) and summed into three subscales (fear of adverse consequences, lack of interest/appetite, and sensory sensitivity); each range = 0-15), with higher scores indicating greater severity.
Measured: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Fear of Food Questionnaire (FFQ) questionnaire
The Fear of Food Questionnaire (FFQ) is an 18-item measure of food-related fears averaged into five subscales (GI fears, food fears, food avoidance, social impairment, and distress/loss of pleasure) and a total score between 0 and 90 (each range = 0-5), with higher scores indicating greater food related fears.
Measured: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Patient Health Questionnaire-12 (PHQ-12) (derived from PHQ-15) questionnaire
PHQ-15 is a validated measure of somatization. Questions reflect the previous 4 weeks. It comprises 15 somatic symptoms with each symptom scored from 0 ("not bothered at all") to 2 ("bothered a lot"). The PHQ-15 will be administered to facilitate assessment of PHQ-12. The PHQ-12 is a commonly used modification of the PHQ-15 without three GI-related items; constipation, loose bowels, or diarrhea; nausea, gas, or indigestion. The PHQ-12 represents non-GI or extraintestinal somatic symptoms.
Measured: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Generalized anxiety disorder (GAD-7) questionnaire
GAD-7 is a 7-item questionnaire used for screening and measuring the severity of anxiety symptoms. Questions reflect the previous 14 days and responses are measured on a 4-point Likert scale; 0=not at all sure; 1=several days; 2=more than half the days; 3=nearly every day. Total GAD-7 scores range from 0-21 with higher scores indicating greater severity of symptoms.
Measured: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Patient Health Questionnaire (PHQ-9) questionnaire
The Patient Health Questionnaire (PHQ-9) is a 9-item measure of depression severity. Questions reflect the previous 14 days. Each of the 9 items can be scored from 0 (not at all) to 3 (nearly every day) and severity score can range from 0 to 27. PHQ-9 scores of 5, 10, 15, and 20 indicate mild, moderate, moderately severe, and severe depression, respectively.
Measured: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Gastrointestinal Specific Anxiety (GSA) measured using Visceral Sensitivity Index (VSI)
The VSI is a 15-item measure of gastrointestinal-specific anxiety, scored on a Likert scale of 1 to 6 with 1=strongly agree; 2=moderately agree; 3=mildly agree; 4=mildly disagree; 5=moderately disagree and 6=strongly disagree.
Measured: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Avoidance behavior measured using Irritable Bowel Syndrome-Behavioural Responses Questionnaire (IBS-BRQ)
IBS-BRQ is a 26-item measure of avoidance behavior. The scale has 26 items, scored from 1 (never) to 7 (always), indicating how persistently the particular avoidance or toilet behavior is carried out.
Measured: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Total FODMAP intake measured using 3-day food diary
Participants will record their food intake for 3 days (including one weekend day) using paper or an app. Total FODMAP intake will be calculated g/day.
Measured: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in stool frequency and consistency using 7-day stool diary based on Bristol Stool Form Scale (BSFS)
The stool diary will be completed over 7 days and is based on the Bristol Stool Form Scale (BSFS) for IBS subtyping and bowel habit assessment i.e. stool frequency and consistency. Stool consistency will be quantified according to ROME classifications.
Measured: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Gastrointestinal microbiome composition and function using stool sample using OMNIgene GUT
Gut microbiome composition (i.e., alpha diversity, beta diversity, relative abundance) and function 16S rRNA and shotgun sequencing. Measured as exploratory mediators.
Measured: Gastrointestinal microbiome composition and function will be measured 2nd weekly between baseline (prior to intervention) and after intervention completed (week 12) as exploratory mediators.
Individual FODMAPs' intake using 3-day food diary
Participants will record their food intake for 3 days (including one weekend day) using paper or an app. Individual FODMAPs' intake will be calculated g/day. Measured as exploratory mediators.
Measured: Will be measured 2nd weekly between baseline (prior to intervention) and after intervention completed (week 12) as exploratory mediators.
Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome GSRS-IBS
The GSRS-IBS is a 13-item measure of IBS symptom severity to reflect the last 7 days. The items are scored between 1 (no discomfort at all) and 7 (very severe discomfort), rendering a total score between 13 and 91. Measured as an exploratory moderator.
Measured: Baseline (prior to start of intervention) as an exploratory moderator.
IBS quality of life (IBS-QOL) questionnaire
Description: I IBS-QOL is used to assess the impact on quality of life for patients with IBS and consists of 34 items scored between 1 and 5, resulting in a maximum score of 170. Measured as an exploratory moderator.
Measured: Baseline (prior to start of intervention) as an exploratory moderator.
Fear of Food Questionnaire (FFQ) questionnaire
The Fear of Food Questionnaire (FFQ) is an 18-item measure of food-related fears averaged into five subscales (GI fears, food fears, food avoidance, social impairment, and distress/loss of pleasure) and a total score between 0 and 90 (each range = 0-5), with higher scores indicating greater food related fears. Measured as an exploratory moderator.
Measured: Baseline (prior to start of intervention) as an exploratory moderator.
Nine Item ARFID (Avoidant Restrictive Food Intake Disorder) Screen (NIAS) questionnaire
NIAS is a 9-item measure of ARFID symptoms. The scale has 9 questions, scored from 0 (strongly disagree) to 5 (strongly agree) and summed into three subscales (fear of adverse consequences, lack of interest/appetite, and sensory sensitivity); each range = 0-15), with higher scores indicating greater severity. Measured as an exploratory moderator.
Measured: Baseline (prior to start of intervention) as an exploratory moderator.
Patient Health Questionnaire-12 (PHQ-12) (derived from PHQ-15) questionnaire
PHQ-15 is a validated measure of somatization. Questions reflect the previous 4 weeks. It comprises 15 somatic symptoms with each symptom scored from 0 ("not bothered at all") to 2 ("bothered a lot"). The PHQ-15 will be administered to facilitate assessment of PHQ-12. The PHQ-12 is a commonly used modification of the PHQ-15 without three GI-related items; constipation, loose bowels, or diarrhea; nausea, gas, or indigestion. The PHQ-12 represents non-GI or extraintestinal somatic symptoms. Measured as an exploratory moderator.
Measured: Baseline (prior to start of intervention) as an exploratory moderator.
Patient Health Questionnaire (PHQ-9) questionnaire
The Patient Health Questionnaire (PHQ-9) is a 9-item measure of depression severity. Questions reflect the previous 14 days. Each of the 9 items can be scored from 0 (not at all) to 3 (nearly every day) and severity score can range from 0 to 27. PHQ-9 scores of 5, 10, 15, and 20 indicate mild, moderate, moderately severe, and severe depression, respectively. Measured as an exploratory moderator.
Measured: Baseline (prior to start of intervention) as an exploratory moderator.
Generalized anxiety disorder (GAD-7) questionnaire
GAD-7 is a 7-item questionnaire used for screening and measuring the severity of anxiety symptoms. Questions reflect the previous 14 days and responses are measured on a 4-point Likert scale; 0=not at all sure; 1=several days; 2=more than half the days; 3=nearly every day. Total GAD-7 scores range from 0-21 with higher scores indicating greater severity of symptoms. Measured as an exploratory moderator.
Measured: Baseline (prior to start of intervention) as an exploratory moderator.
Gastrointestinal microbiome composition and function using stool sample using a stool sample collection kit.
Gut microbiome composition (i.e., alpha diversity, beta diversity, relative abundance) and function 16S rRNA and shotgun sequencing . Measured as an exploratory moderator.
Measured: Baseline (prior to start of intervention) as an exploratory moderator.
IBS subtype using 7-day stool diary based on Bristol Stool Form Scale (BSFS).
The stool diary will be completed over 7 days and is based on the Bristol Stool Form Scale (BSFS) for IBS subtyping and bowel habit assessment i.e. stool frequency and consistency. Stool consistency will be quantified according to ROME classifications. Measured as a exploratory moderator.
Measured: Baseline (prior to start of intervention) as an exploratory moderator.
Client Satisfaction Questionnaire
The Client Satisfaction Questionnaire is an 8-question brief global measure of client satisfaction. The eight questions are measured on a 4-point Likert scale with questions 1, 3, 6 and 7 measured on a positive scale and questions 2, 4, 5 and 8 on a negative scale. Total scores range from 8 to 32, with the higher number indicating greater satisfaction.
Measured: End of the 12-week intervention and at 3-and 6 months follow up time points after 12-week intervention..
Proportion of participants who achieve a change from baseline in Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome (GSRS-IBS) of ≥30% total score
The GSRS-IBS is a 13-item measure of IBS symptom severity to reflect the last 7 days. The items are scored between 1 (no discomfort at all) and 7 (very severe discomfort), rendering a total score between 13 and 91.
Measured: Baseline and after intervention completed (week 12)
Proportion of participants who achieve a change from baseline in Irritable Bowel Syndrome - Symptom Severity Score (IBS-SSS) of ≥50 points total score.
The IBS-SSS is a 5-item measure of the severity of IBS symptoms: frequency and severity of abdominal pain, severity of bloating, dissatisfaction with bowel habits and impact on life in general. Questions ask about IBS and gut symptoms during the past 7 days with the exception of question 4 which asks participants to enter the number of days they get pain in every 10. days. A total score ranging from 0 to 500. Mild, moderate and severe cases are indicated by scores of 75 to <175, 175 to <300 and >300 respectively
Measured: Baseline and after intervention completed (week 12)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Apr 2025
- Study start22 May 2025
- Primary completionOct 2027 (estimated)
- Study completionApr 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Irritable Bowel Syndrome (IBS)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be randomized to one of two treatment arms. The randomization schedule will be generated using http://www.randomization.com. Participants will be stratified by site (Australia or US) before randomization.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 235 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Melbourne
- Sponsor type
- University, hospital or other
- Collaborators
- Monash University
- Responsible party
- Sponsor
- Investigators
- Associate Professor Jessica Biesiekierski, Principal investigator, University of Melbourne
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06940596
- Sponsor's protocol ID
- CT31293
- Other IDs
- 2024, APP2025943
- Status last verified
- Apr 2026
- First submitted
- 31 Mar 2025
- Last updated
- 6 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Potential data shared includes: * Individual participant data that underlie the results reported in the article after de-identification (text, tables, figures and appendices) * Trial protocol * Statistical Analysis Plan * Participant Information Consent Form
Publications
Biesiekierski JR, Manning LP, Murray HB, Vlaeyen JWS, Ljotsson B, Van Oudenhove L. Review article: exclude or expose? The paradox of conceptually opposite treatments for irritable bowel syndrome. Aliment Pharmacol Ther. 2022 Aug;56(4):592-605. doi: 10.1111/apt.17111. Epub 2022 Jul 1.
PubMed 35775328
Study at a glance
From the registry record, last updated by the sponsor on 6 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Exclude or Expose in Irritable Bowel Syndrome: What Works for Whom, and How? A Randomized Controlled Trial of Internet-Delivered FODMAP Diet Versus Exposure-Based Cognitive Behavioral Therapy
- ClinicalTrials.gov ID
- NCT06940596
- Acronym / sponsor ID
- CT31293
- Keywords
- Irritable Bowel Syndrome, FODMAP Diet, Behavior Therapy, Gastrointestinal Diseases, Cognitive Behavioral Therapy, Exposure Based Cognitive Behavioral Therapy, Intestinal Diseases, Digestive System Diseases
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 235 participants (estimated)
- Lead sponsor
- University of MelbourneUniversity, hospital or other
- Collaborators
- Monash University
- Study start
- 22 May 2025 (actual)
- Primary completion
- Oct 2027 (estimated)
- Study completion
- Apr 2028 (estimated)
- First posted
- 23 Apr 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This research project will assess how two treatments for irritable bowel syndrome (one dietary and one behavioral) work and for whom. This will be done by assessing moderators (what treatment works for who and in what context) and mediators (how treatment works). Investigators will also assess how the diet and behavioral treatments affect IBS symptoms during treatment. Participants will be randomized to either: i. A FODMAP diet online program that focuses on modifying the consumption of foods high or moderate in fermentable carbohydrates (FODMAPS) to manage IBS symptoms. or, ii. An Exposure-based Cognitive Behavioral Therapy (E-CBT) online program for IBS that focuses on changing symptom-related behaviors which are known to worsen IBS symptoms.
Detailed description
This research uses a randomized controlled trial to investigate the treatment of irritable bowel syndrome (IBS). A range of treatments for IBS are available, but each work for only a portion of patients, and it is unclear why. This research project will assess how two treatments (one dietary and one behavioral) work and for whom. Investigators will do this by assessing moderators (what treatment works for who and in what context) and mediators (how treatment works). This project will also assess how the diet and behavioral treatments affect IBS symptoms during treatment. Participants will be randomized to either: i. A FODMAP diet online program that focuses on modifying the consumption of foods high or moderate in fermentable carbohydrates (FODMAPS) to manage IBS symptoms. This treatment involves 3-phases: FODMAP restriction (phase 1), FODMAP re-introduction (phase 2), and FODMAP personalization (phase 3), or, ii. An Exposure-based Cognitive Behavioral Therapy (E-CBT) online program for IBS that focuses on symptom-related behaviors such as avoidance of activities and foods, excessive toilet visits, and behaviors to control symptoms which are known to worsen IBS symptoms. E-CBT uses daily self-observation and exposure exercises to change these behaviors to relieve IBS symptoms. Investigators believe that both treatments, FODMAP diet and E-CBT, will lead to an improvement in IBS gastrointestinal symptoms. Primary moderators and mediators to be assessed include gastrointestinal symptom anxiety, food avoidance behaviour and FODMAP intake.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
- Model description
- Participants will be randomized to one of two treatment arms. The randomization schedule will be generated using http://www.randomization.com. Participants will be stratified by site (Australia or US) before randomization.
| Arm | Type | Receives |
|---|---|---|
| FODMAP Diet | Experimental | Other: FODMAP DietFermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) Diet is a 12-week online intervention with dietitian support. |
| Exposure-based Cognitive Behavioral Therapy (E-CBT) | Experimental | Behavioral: Exposure-based Cognitive Behavioral TherapyExposure-based Cognitive Behavioral Therapy is a 12-week online intervention with psychologist support. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| FODMAP DietThe intervention is an online diet program. The diet is the low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet. It is a 3-phase diet which involves: 1.Phase 1 FODMAP restriction: restrict foods high or moderate in FODMAPs and swap these for low FODMAP alternatives; 2. Phase 2 FODMAP reintroduction: continue to follow a low FODMAP diet and complete a series of food challenges to understand which foods and FODMAPs are tolerated and which trigger symptoms; 3. Phase 3 FODMAP personalization: include well-tolerated foods and FODMAPs back into the diet, and restrict poorly tolerated foods and FODMAPs to a level needed to maintain symptom relief. The online FODMAP program is a self-directed diet program with support from an online clinician (Accredited Practicing Dietitian [APD]). The content is delivered over 12 weeks. After each module participants will complete homework activities and questions and submit them to the dietitian for feedback. | Other | FODMAP Diet |
| Exposure-based Cognitive Behavioral TherapyThe intervention is an online behavioral therapy program. The behavioral therapy is Exposure-based Cognitive Behavioral Therapy (E-CBT) Program. The E-CBT program is organised into six steps to be completed over 12 weekly modules with support from an online clinician (Psychologist). The first step contains a rationale for the treatment and instructions on self-observation. Steps 2, 3 and 4 contain a presentation of a psychological model of IBS and continued self-observation exercises. The fifth step covers exposure exercises, divided into three categories; (1) exercises that provoke symptoms, (2) abolishment of behaviors that serve to control symptoms, (3) exposure to situations where symptoms were unwanted. The final step (Step 6) includes how to handle relapses into avoidance behaviors and how to maintain a widened behavioral repertoire. After each module participants will be directed to complete homework activities and questions and submit them to the psychologist for feedback. | Behavioural | Exposure-based Cognitive Behavioral Therapy (E-CBT) |
Primary outcome
Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome (GSRS-IBS )
Time frame: Measured weekly between baseline (prior to intervention) and after intervention completed (week 12).
The GSRS-IBS is a 13-item measure of IBS symptom severity to reflect the last 7 days. The items are scored between 1 (no discomfort at all) and 7 (very severe discomfort), rendering a total score between 13 and 91.
26 secondary outcomes
Change from baseline in Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome (GSRS-IBS)
Time frame: Baseline and 3-and 6 month follow up time points after intervention completed (week 12).
Change from baseline in Irritable Bowel Syndrome - Symptom Severity Score (IBS-SSS) questionnaire
Time frame: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in IBS quality of life (IBS-QOL) questionnaire
Time frame: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Nine Item ARFID (Avoidant Restrictive Food Intake Disorder) Screen (NIAS) questionnaire
Time frame: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Fear of Food Questionnaire (FFQ) questionnaire
Time frame: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Patient Health Questionnaire-12 (PHQ-12) (derived from PHQ-15) questionnaire
Time frame: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Generalized anxiety disorder (GAD-7) questionnaire
Time frame: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Patient Health Questionnaire (PHQ-9) questionnaire
Time frame: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Gastrointestinal Specific Anxiety (GSA) measured using Visceral Sensitivity Index (VSI)
Time frame: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Avoidance behavior measured using Irritable Bowel Syndrome-Behavioural Responses Questionnaire (IBS-BRQ)
Time frame: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in Total FODMAP intake measured using 3-day food diary
Time frame: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Change from baseline in stool frequency and consistency using 7-day stool diary based on Bristol Stool Form Scale (BSFS)
Time frame: Baseline, after intervention completed (week 12), and at follow up time points of 3-and 6 months following the 12-week intervention.
Gastrointestinal microbiome composition and function using stool sample using OMNIgene GUT
Time frame: Gastrointestinal microbiome composition and function will be measured 2nd weekly between baseline (prior to intervention) and after intervention completed (week 12) as exploratory mediators.
Individual FODMAPs' intake using 3-day food diary
Time frame: Will be measured 2nd weekly between baseline (prior to intervention) and after intervention completed (week 12) as exploratory mediators.
Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome GSRS-IBS
Time frame: Baseline (prior to start of intervention) as an exploratory moderator.
IBS quality of life (IBS-QOL) questionnaire
Time frame: Baseline (prior to start of intervention) as an exploratory moderator.
Fear of Food Questionnaire (FFQ) questionnaire
Time frame: Baseline (prior to start of intervention) as an exploratory moderator.
Nine Item ARFID (Avoidant Restrictive Food Intake Disorder) Screen (NIAS) questionnaire
Time frame: Baseline (prior to start of intervention) as an exploratory moderator.
Patient Health Questionnaire-12 (PHQ-12) (derived from PHQ-15) questionnaire
Time frame: Baseline (prior to start of intervention) as an exploratory moderator.
Patient Health Questionnaire (PHQ-9) questionnaire
Time frame: Baseline (prior to start of intervention) as an exploratory moderator.
Generalized anxiety disorder (GAD-7) questionnaire
Time frame: Baseline (prior to start of intervention) as an exploratory moderator.
Gastrointestinal microbiome composition and function using stool sample using a stool sample collection kit.
Time frame: Baseline (prior to start of intervention) as an exploratory moderator.
IBS subtype using 7-day stool diary based on Bristol Stool Form Scale (BSFS).
Time frame: Baseline (prior to start of intervention) as an exploratory moderator.
Client Satisfaction Questionnaire
Time frame: End of the 12-week intervention and at 3-and 6 months follow up time points after 12-week intervention..
Proportion of participants who achieve a change from baseline in Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome (GSRS-IBS) of ≥30% total score
Time frame: Baseline and after intervention completed (week 12)
Proportion of participants who achieve a change from baseline in Irritable Bowel Syndrome - Symptom Severity Score (IBS-SSS) of ≥50 points total score.
Time frame: Baseline and after intervention completed (week 12)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 May 2026.
- Background: PubMed 35775328Biesiekierski JR, Manning LP, Murray HB, Vlaeyen JWS, Ljotsson B, Van Oudenhove L. Review article: exclude or expose? The paradox of conceptually opposite treatments for irritable bowel syndrome. Aliment Pharmacol Ther. 2022 Aug;56(4):592-605. doi: 10.1111/apt.17111. Epub 2022 Jul 1.
- Individual participant dataSharing planned: Yes. Potential data shared includes: * Individual participant data that underlie the results reported in the article after de-identification (text, tables, figures and appendices) * Trial protocol * Statistical Analysis Plan * Participant Information Consent Form
Related trials for Irritable Bowel Syndrome (IBS)
RecruitingObservational study
Abdominal Symptoms and Rosacea: An Observational Study on the Association Between Irritable Bowel Syndrome (IBS) and the Gut-Skin Axis
IBS (Irritable Bowel Syndrome), Rosacea
Recruiting
Stress Reduction and Lifestyle Modification in Irritable Bowel Syndrome Patients
Irritable Bowel Syndrome
Recruiting
Exercise Interventions and Dietary Advice in Fibromyalgia and IBS
Fibromyalgia, Irritable Bowel Syndrome
RecruitingPhase 2
A Study of Brenipatide (LY3537031) in Participants With Irritable Bowel Syndrome-Constipation (IBS-C)
Irritable Bowel Syndrome, Constipation
RecruitingPhase 2
A Study of Brenipatide (LY3537031) in Participants With Irritable Bowel Syndrome-Diarrhea (IBS-D)
Irritable Bowel Syndrome, Diarrhea
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Jacqueline L Anderson, APD contact
Associate Professor Jessica Biesiekierski principal investigator
University of Melbourne
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing FODMAP Diet and Exposure-based Cognitive Behavioral Therapy in people with Irritable Bowel Syndrome (IBS) and Intestinal Diseases, run by University of Melbourne at 1 site in Australia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 6 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Australia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Jessica Biesiekierski, A/Prof (+61 499 272 673, jessica.biesiekierski@unimelb.edu.au), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome (GSRS-IBS ) (time frame: Measured weekly between baseline (prior to intervention) and after intervention completed (week 12).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06940596, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 May 2026.