Principal investigator left the institution

This study evaluates the effectiveness of a group cognitive behaviour therapy for Irritable Bowel Syndrome (IBS) in decreasing symptoms of IBS, improving quality of life, and normalizing the gut microbiome. Patients will complete an 11-week group cognitive behaviour therapy for IBS within 1 month of being deemed eligible for the study.

Irritable bowel syndrome (IBS) is a chronic, disabling functional gastrointestinal disorder that is characterized by abdominal pain or discomfort and a disturbance in bowel habit. Approximately five million Canadians currently suffer with this chronic illness, which can have a significant impact on work and school absenteeism, productivity, social functioning and quality of life (Fedorak et al., 2012). Although the etiology of IBS is still unclear, there is increased interest in the role of the gut-brain axis in the development and maintenance of IBS. A growing body of evidence has identified changes in the composition, temporal stability and metabolic activity of the gut microbiome in IBS (Bolino & Bercik, 2010). Moreover, there is evidence for bidirectional communication between the gut and the brain, such that the gut microbiota appear to influence as well as be modulated by brain activity through neurohumoral mechanisms (Collins, Surette, & Bercik, 2012).

Currently, medications are the most widely used treatment for IBS (Ford et al., 2009; Ford et al., 2014). Although there is good evidence for the effectiveness of medications in reducing IBS symptomatology and improving quality of life, these medications are also often associated with unpleasant side effects. As a result, there is a growing interest in the utilization of psychological treatments, including cognitive behaviour therapy, for IBS. Cognitive behaviour therapy is a psychotherapeutic approach that addresses maladaptive cognitive processes and behaviours in a systematic, explicit fashion. Although there is good evidence for the effectiveness of cognitive behaviour therapy for the treatment of IBS (Ford et al., 2009; Ford et al., 2014), there is a lack of research examining the mechanisms through which cognitive behaviour therapy influences symptoms of IBS.

Accordingly, the current study has three aims: 1) to evaluate the effectiveness of group cognitive behaviour therapy for IBS on IBS symptomatology and quality of life; 2) to examine whether there are any changes in the gut microbiome from pre to posttreatment; and 3) to examine whether changes in the gut microbiome following cognitive behaviour therapy mediate changes in IBS symptomatology and quality of life. The current study has the potential of increasing knowledge about the role of the gut microbiome in IBS as well as the mechanisms of cognitive behaviour therapy for IBS.

Inclusion Criteria:

• Diagnosed with irritable bowel syndrome
• Able to commit to attending weekly 2-hour group sessions for 12 weeks

Exclusion Criteria:

• Use of antibiotics, or probiotics during the 4-week period prior to enrolling in the study
• Changes in medications during the 4-week period prior to enrolling in the study
• Presence of a major medical illness that may change the gut microbiome (e.g., any comorbid gastroenterological, rheumatological, or immunological disorder)
• Diagnosis of a major psychiatric disorder that is likely to impede participation in group therapy (e.g., depression with active suicidality, psychosis, or gross cognitive impairment)
• Received psychotherapy for IBS within the past 5 years
• Inability to read or complete symptom diaries or questionnaires
• Inability or unwillingness to provide or sign informed consent