Lin, KCavadino, AOw, MDouglas, MeihanaSerlachius, A2025-08-062025-08-062025-06-26Frontiers in Digital Health, ISSN: 2673-253X (Print); 2673-253X (Online), Frontiers Media SA, 7, 1587765-. doi: 10.3389/fdgth.2025.15877652673-253X2673-253Xhttp://hdl.handle.net/10292/19647Introduction: Inflammatory bowel disease (IBD) is associated with high rates of depression and anxiety. Acceptance and Commitment Therapy (ACT) has demonstrated utility across different chronic health conditions, and online ACT interventions may potentially improve access to mental health support. Methods: This study was a parallel two-arm randomised controlled trial that investigated the effects a brief seven-day online ACT intervention (iACT4IBD) on psychological and physical health outcomes. We examined whether iACT4IBD could reduce depressive symptoms in adults with IBD compared to a waitlist control group at 4-weeks follow-up. Effects of iACT4IBD on levels of anxiety, stress, wellbeing, quality of life, and IBD activity were also explored. Seventy adults with IBD (Crohn's disease and ulcerative colitis) were randomly allocated to either the iACT4IBD intervention or a waitlist control group. Psychological and physical health outcomes were collected at baseline, 4-weeks and 8-weeks after baseline. Outcome measures were assessed at baseline and 4-weeks follow-up using mixed ANOVAs. Results: No between-group differences in psychological outcomes were found from baseline to 4-weeks follow-up. Crohn's disease activity scores in the intervention group were significantly lower after 4-weeks compared to the waitlist control group. Qualitative feedback suggested that the intervention was acceptable and beneficial. Discussion: There were no improvements to mental wellbeing; however, findings provided some support for the intervention improving physical health in people with Crohn's disease. Further research is needed. Clinical Trial Registration: Australian New Zealand Clinical Trials Registry (U1111-1282-2334).Copyright: © 2025 Lin, Cavadino, Ow, Douglas and Serlachius. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Crohn's diseaseacceptance and commitment therapyinflammatory bowel diseaseonline interventionulcerative colitis4203 Health Services and Systems42 Health SciencesInflammatory Bowel DiseaseBehavioral and Social ScienceDepressionMental HealthClinical ResearchMental IllnessClinical Trials and Supportive ActivitiesCrohn's DiseaseComplementary and Integrative HealthMinority HealthBrain DisordersAutoimmune DiseaseHealth Disparities and Racial or Ethnic Minority Health ResearchDigestive DiseasesHealth Disparities6.6 Psychological and behaviouralMental healthOral and gastrointestinal3 Good Health and Well Being4203 Health services and systemsJournal ArticleOpenAccess10.3389/fdgth.2025.1587765