Persistence of gastrointestinal symptoms in irritable bowel syndrome and ulcerative colitis: from risk factors to modification

INTERVENTION: We will use the design of a three‐arm randomised‐controlled trial (RCT). A fixed randomisation schedule, stratified by diagnostic group and sex, will be programmed and conducted electronically. Experimental intervention 1 (GUT.EXPECT + SC): This experimental intervention consists of an expectation management intervention (GUT.EXPECT) in addition to standard care (SC). The manualised intervention primarily aims at optimising expectations about symptoms, treatment outcome, and coping strategies and at reducing illness anxiety. The design of the intervention is based on the preferences expressed by patients in a pilot study, the demonstrated effectiveness of the expectation management intervention from the PSY‐HEART and the PSY‐BREAST trials, and other previous studies. The intervention consists of 3 individual online consultation sessions in intervals of 2 weeks each and a booster session after 3 months, with each session lasting 45 minutes. Homework will be given after each session to deepen the acquired skills. The intervention thus addresses the topics "dealing with anxiety", "improving expectations" as well as patients’ need for information about their disease. Experimental intervention 2 (GUT.SUPPORT + SC): This experimental intervention consists of a non‐specific supportive intervention (GUT.SUPPORT) in addition to SC. GUT.SUPPORT is identical to GUT.EXPECT in terms of common and non‐specific treatment elements, i.e. time, personal attention and emotional support, but does not use specific interventions aimed at modifying expectations and illness anxiety. Control intervention (standard care): The control intervention consists of SC only CONDITION: Gastrointestinal symptoms in patients with irritable bowel syndrome or ulcerative colitis ; Digestive System PRIMARY OUTCOME: Gastrointestinal symptom severity assessed using the Irritable Bowel Syndrome ‐ Severity Scoring System (IBS‐SSS) at baseline, after 6 weeks, after 3 months (post‐interventional follow‐up), after 6 and 12 months INCLUSION CRITERIA: 1. Diagnosis of ulcerative colitis (UC) or irritable bowel syndrome (IBS; Rome IV); 2. at least moderate gastrointestinal symptoms according to the Irritable Bowel Syndrome ‐ Severity Scoring System (IBS‐SSS = 175); 3. UC/IBS treatment according to current German AWMF guidelines; 4. informed consent. SECONDARY OUTCOME: ; 1. Total somatic symptom severity measured using the Patient Health Questinnaire‐15 (PHQ‐15) at baseline, 6 weeks, 3 months, 6 months, and 12 months.; 2. Illness related anxiety measured using the Somatic Symptom Disorder – B‐Criteria Scale (SSD‐12) at baseline, 6 weeks, 3 months, 6 months. and 12 months.; 3. Expectations of symptom severity measured using a Numeric Rating Scale (NRS) at baseline, 6 weeks, 3 months, 6 months, and 12 months.; 4. Expectations of coping with symptoms measured using a Numeric Rating Scale (NRS) at baseline, 6 weeks, 3 months, 6 months, and 12 months.; 5. Treatment expectations measured using the Treatment Expectation Questionnaire (TEX‐Q) at baseline, 6 weeks, 3 months, 6 months, and 12 months.; 6. Disease activity (ulcerative colitis only) measured using the Simple Clinical Colitis Activity Index (SCCAI) at baseline, 6 weeks, 3 months, 6 months, and 12 months.; 7. Time to next treatment measured using a single question at baseline, 6 weeks, 3 months, 6 months, and 12 months.; 8. Utilisation of medical treatment measured using a single question at baseline, 6 weeks, 3 months, 6 months, and 12 months.; 9. Adverse effects measured using a single question at baseline, 6 weeks, 3 months, 6 months, and 12 months.; 10. Satisfaction with interventions measured using a Numeric Rating Scale (NRS) at 3 months.; 11. Systemic inflammation measured using C‐reactive protein (CRP), interleukin 6 (IL‐6), and tumour necrosis factor (TNF) at baseline and 3 months.; 12. Intestinal inflammation measured using faecal calprotectin at baseline and 3 months.; 13. Risk factors of somatic symptom persistence measured using the SOMACROSS research unit’s core instruments at baseline, 3 months, 6 months, and 12 months.;