Well-being in IBS: Strengths and Happiness (WISH) 2.0

Feasibility will be measured by the proportion of intervention sessions completed by participants. The intervention will be considered feasible if at least 50% of participants complete at least 6/9 sessions.

Participants will provide ratings of ease after each weekly exercise, measured on a 10-point Likert scale (0=very difficult, 10=very easy).

Participants will provide ratings of utility after each weekly exercise, measured on a 10-point Likert scale (0=not at all helpful; 10=very helpful).

Participants will provide ratings of optimism before and after each positive psychology exercise, measured on a 10-point Likert scale (0-10). Higher scores indicate higher levels of optimism.

Participants will provide ratings of happiness before and after each positive psychology exercise, measured on a 10-point Likert scale (0-10). Higher scores indicate higher levels of happiness.

Participants will provide ratings of knowledge about IBS before and after each educational exercise, measured on a 10-point Likert scale (0-10). Higher scores indicate higher levels of knowledge.

Measured by the IBS symptom severity score (IBS-SSS) (Range 0-500). This is a validated disease-specific instrument that measures IBS symptom severity. Higher scores indicate more severe symptoms.

Measured by the IBS Quality of Life (IBS-QOL) score (Range: 0-100), a validated disease-specific instrument measuring quality of life. Higher scores indicate better IBS-specific quality of life.

Measured by the The Rome-IV Diagnostic Questionnaire - IBS Module, which is a validated disease-specific instrument used to screen for IBS diagnostic criteria and to provide a provisional (yes/no) diagnosis of IBS. To meet criteria for IBS, the following are required for the past 3 months: (1) recurrent abdominal pain at least weekly; (2) pain associated with 2 or more of the following criteria: a) related to defecation at least 30% of occasions; b) associated with change in stool frequency at least 30% of occasions; c) associated with change in stool form at least 30% of occasions; and (3) symptom onset at least 6 months prior to diagnosis.

Measured with the positive affect items on the Positive and Negative Affect Schedule (PANAS), a well-validated scale used in other intervention trials and in patients with medical illnesses (Range: 10-50). Higher scores indicate higher levels of positive affect.

Measured with the Life Orientation Test-Revised (LOT-R), a well-validated 6-item instrument used to measure dispositional optimism (Range: 0-24). Higher scores indicate higher levels of optimism.

Measured with the Brief State Optimism Measure (B-SOM), a validated 2-item instrument used to measure state optimism (Range: 0-100 for each item). Higher scores indicate greater state optimism.

Measured by the Brief Resilience Scale (BRS) (Range: 6-30), a reliable 6-item measure of the ability to "bounce back" or recover from stress. Higher scores reflect greater bounce back resilience.

Measured by the General Self-Efficacy (GSE) Scale (Range: 10-40), a 10-item validated measure of self-efficacy, defined as an individual's perception of their ability to succeed at a task or achieve a goal. Higher scores indicate greater self-efficacy.

Measured by the Hospital Anxiety and Depression Scale (HADS)-depression subscale. This is a well-validated scale with few somatic symptom items that can confound mood/anxiety assessment in medically-ill patients (Range: 0-21). Higher scores indicate higher levels of depression.

Measured by the Hospital Anxiety and Depression Scale (HADS)-anxiety subscale. This is a well-validated scale with few somatic symptom items that can confound mood/anxiety assessment in medically-ill patients (Range: 0-21). Higher scores indicate higher levels of anxiety.

Measured by the Visceral Sensitivity Index (VSI) score, a validated self-report measure of anxiety specific to visceral sensations (Range: 0-75). Higher scores indicate higher levels of GI-specific anxiety.

Measured by the Pain Catastrophizing Scale (PCS), a widely used tool to assess cognitive and affective responses to pain (Range: 0-52). Higher scores indicate higher levels of pain-related anxiety.

Measured by the Perceived Stress Scale (PSS) (Range: 0-40), a validated measure to assess perceived levels of stress. Higher scores indicate higher perceived stress.

Measured by the self-report International Physical Activity Questionnaire (IPAQ) Short Form. This 7-item measure assesses self-reported physical activity from the preceding 7 days. All activities are converted to multiples of resting energy expenditure (MET) minutes per week. Higher scores reflect higher levels of physical activity.

Measured by the Nine Item Avoidant/Restrictive Food Intake Disorder screen (NIAS) (Range: 0-45), a validated tool to assess avoidant/restrictive eating patterns. Higher scores indicate higher levels of avoidant/restrictive eating patterns.

The Multidimensional Assessment of Interoceptive Awareness-Version 2 (MAIA-2) is a validated measure of interoception, defined as an awareness of internal bodily sensations (Range: 0-185). Higher scores indicate a higher level of interoceptive bodily awareness.

Heart-rate variability measurements will be collected to explore changes in autonomic function related to the intervention.

Whole transcriptome analysis of blood samples by RNA sequencing (RNA-seq) will be completed to explore gene expression changes related to the intervention.

Blood inflammatory biomarker levels will be assessed to explore changes in immune system activity related to the intervention.

The Credibility sub-scale (Range: 3-27) of the Credibility/Expectancy Questionnaire (CEQ) will be used to compare treatment credibility between conditions. Higher scores indicate higher treatment credibility.

The Expectancy sub-scale (Range: 3-27) of the Credibility/Expectancy Questionnaire (CEQ) will be used to compare treatment expectancy between conditions. Higher scores indicate higher treatment expectancy.