Aim: Gut directed hypnotherapy can reduce IBS symptoms but the mechanisms underlying this therapeutic effect remain unknown. We determined the effect of hypnotherapy and educational intervention on brain responses to cued rectal distensions in IBS patients. Methods: 44 women with moderate to severe IBS and 20 healthy controls (HCs) were included.. Blood oxygen level dependent (BOLD) signals were measured by functional Magnetic Resonance Imaging (fMRI) during expectation and delivery of high (45 mmHg) and low (15 mmHg) intensity rectal distensions. Twenty-five patients were assigned to hypnotherapy (HYP) and 16 to educational intervention (EDU). 31 patients completed the treatments and the post treatment fMRI. Results: Similar symptom reduction was achieved in both groups. HYP responders demonstrated a pre-post treatment BOLD attenuation in both anterior and posterior insula during high intensity distension, while EDU responders had a BOLD attenuation in prefrontal cortex. Pre-post differences for the low distension and for the two expectation conditions were almost exclusively seen in the HYP group. For all responders there was a significant correlation between treatment induced reduction of GI related anxiety and BOLD decrease in the anterior insula. Following treatment, the brain response to distension was similar to that observed in HCs, suggesting that the treatment had a normalizing effect on the central processing abnormality of visceral signals in IBS. Conclusions: The abnormal processing and enhanced perception of visceral stimuli in IBS can be normalized by psychological interventions. Symptom improvement in the treatment groups may be mediated by different brain mechanisms.

Inclusion Criteria:

Rome III Female Age 20-60 Swedish speaking Right-handed

Exclusion Criteria:

Central acting medication IBD Psychiatric diseases Abdominal surgery NictoinePacemaker Prosthesis Metal in the brain Claustrophobia Large tattoo

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