Vagal Nerve Stimulation in Irritable Bowel Syndrome

This randomized control trial aims to evaluate the effect of transcutaneous auricular vagal nerve stimulation in patients with irritable bowel syndrome. The intervention will be 8 weeks of treatment with a vagal nerve stimulator. The main objectives are: * To evaluate the clinical response, defined as a decrease of at least 50 points on the IBS-SSS questionnaire, of the treatment. * To ascertain whether the autonomic-vagal neurosignature, derived from pre-treatment registration of symptom profiles, autonomic responses and imaging of neuronal activity as a reaction to stress is able to predict therapeutic response to tVNS accurately. * To evaluate the effect of treatment on quality of life * To evaluate the effect of treatment on depression * To evaluate the effect of treatment on anxiety Participants will be asked to wear a wearable (Fitbit) and fill out a daily questionnaire for one week. Thereafter, a functional brain MRI will be performed. In the intervention group patients will receive transcutaneous nerve stimulation for 8-weeks at home. The comparison group will receive the same device but with a non-conducting electrode. Patients fill out weekly questionnaires during the treatment period and at follow-up moments 3 and 6 months after finishing the treatment period.