Inclusion Criteria:  Rome IV IBS diagnosis Indicate moderate to high levels of psychological distress over the past two weeks (composite score >5 on the Patient Health Questionnaire-4) Willingness to provide assessments of bowel symptoms and complete study measures (including smartphone assessments) Willingness/availability to be randomized and participate in all study activities  Exclusion Criteria:  Non-English speaking Report a new diagnosis of a (non-acute) medical or psychiatric condition requiring treatment within the last 3 months Report current drug abuse (e.g., binge drinking) Have a history of diagnosed IBD or gastrointestinal malignancies. Currently receiving treatments that inhibit immune function (e.g., steroids, biologic medications, chemotherapy, or immunosuppressants) Begun any new treatments for IBS in the four weeks prior to baseline