Naam Carla Flik
Datum verdediging 21-06-2018
(Co) promotoren prof.dr. N.J. de Wit, prof.dr. A.J.P.M. Smout, dr. Y.W. van Rood, dr.ir. W. Laan
Titel proefschrift Hypnotherapy in the management of irritable bowel syndrome

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Samenvatting proefschrift
Irritable Bowel Syndrome (IBS) is the most common functional gastrointestinal disorder in the population. The effectiveness of hypnotherapy in treating IBS has been demonstrated but mainly for patients with refractory symptoms, in an individual setting. We designed the IMAGINE study to assess the effectiveness of hypnotherapy, delivered in a group and individual setting in patients with IBS referred from primary and secondary care. Methodological challenges in studies on psychological interventions are adequate selection of the study population, use of valid diagnostic inclusion criteria and study outcomes, and the design of an optimal placebo control intervention. After studying the (mis)conceptions and information wishes that IBS patients have we designed an educational program as control intervention, consisting of explanation of IBS, life-style measures and ways of coping with stress and symptoms. To assess the most cost-effective treatment location we compared costs for IBS patients treated in primary or secondary care. For primary care patients, the mean total annual health care costs for the three years after diagnosis of IBS compared to the three years before diagnosis, increased with 486 Euro, whereas for secondary care patients, these costs increased with 2328 Euro. For controls there was no significant difference. We concluded that non complicated IBS should preferably be treated in primary care. Subsequently we investigated the placebo response rate (PRR) in psychological treatment for IBS. Based on systematic review of six studies we calculated a pooled PRR of 41.4%, which is comparable to that of studies on drug therapy for IBS. Based on qualitative assessment we concluded that it is not the content of the intervention, but patient-related factors, such as expectations and desire for treatment effectiveness, that determine the PRR. In a systematic review on effectiveness of psychological interventions, we identified five studies with an adequate control group comparison. Only mindfulness and relaxation therapy appeared to be more effective than the placebo control. Finally, in a randomised controlled trial (RCT), 354 patients with IBS (aged 18-65) and referred by primary and secondary care were treated with 6 sessions of individual hypnotherapy (IHT), group hypnotherapy (GHT) or educational supportive therapy (EST). After three months of therapy, the primary outcome ‘adequate relief’ was met in 40.2% of the patients in the IHT group, 34.1% in the GHT group and in 17.1% in the EST group. At 12 months these figures were 41.8%,50.0% and 22.6% respectively.General conclusion was that hypnotherapy is an effective treatment for IBS patients from primary and secondary care, which should be offered to patients in whom the first two treatment steps (lifestyle advise and medication) are not effective. Group application may make hypnotherapy better accessible and reduce costs.​