Discussion
We here report the results from two randomized, controlled trials evaluating gut-directed hypnotherapy as a treatment option for severe IBS. The studies were performed in two different clinical settings, outside highly specialized hypnotherapy units, in order to evaluate the potential to have this therapy more widely spread compared to what is the case today. In study 1, the patients were included at a gastroenterological department at a university hospital, highly specialized in functional GI diseases, but the therapy was given outside the hospital in psychology private practices. Study 2 was performed in a medium-sized county hospital with a small gastroenterological department. Both studies aimed to evaluate gut-directed hypnotherapy in IBS with improvement in GI symptoms as the primary end point and improvement in QOL and impact on psychological well-being as secondary end points. The two studies are reported separately, but might be compared as the studies are similar.
The main finding of this study was a significant reduction in IBS symptoms in both studies in the gut-directed hypnotherapy groups. This was more pronounced for sensory symptoms, such as pain and bloating, than for bowel habit disturbances. However, in study 1, the severity of constipation and diarrhea was combined in a composite bowel habit score, which might have prevented the possibility to detect improvement in diarrhea and/or constipation, but also in study 2, the positive effect was more obvious for pain and bloating than for bowel habits. No improvement in GI-symptom severity was seen in the control groups. When comparison was made between the treatment and control groups, the differences in IBS symptoms reached statistical significance in study 1, but not in study 2, potentially due to smaller sample size in study 2. The effects on GI symptoms were sustained up to the 1-year follow-up in both studies. We also noted a positive effect on some of our secondary end points. Improvements in some of the QOL dimensions were seen after hypnotherapy, and anxiety tended to be lower after hypnotherapy, which is in line with previous findings. However, the improvements seen in QOL did not differ significantly between the active group and the controls at 3 months.
The results of our study do not reach the level of effect reported by the Manchester group but are comparable to some other controlled, randomized studies assessing the effect of gut-directed hypnotherapy as a treatment option for severe IBS patients. Our results may reflect the fact that the psychologists in our studies are not highly specialized and experienced in gut-directed hypnotherapy, which is the case in most other studies previously presented. Also, the fact that we did not use audiotapes in study 1 may have influenced our results, even though the subjects were instructed to practice their skills at home regularly between the sessions. Moreover, a more pronounced placebo effect with the hypnotherapy given at highly specialized centers, due to unspecific psychological effects, such as higher treatment expectation, might be expected. Our results reflect the effectiveness of this intervention when given outside the studies performed by highly specialized therapists with long experience in gut-directed hypnotherapy. When asked after the study, most of our patients responded that they had a very positive experience of the hypnotherapy in terms of general well-being and that they had found a way to cope with their symptoms. This is in contrast with the fact that some of them did not report so much improvement in GI-symptom severity, when completing the symptom questionnaires. Measuring GI-symptom severity with questionnaires as the primary end point may not be the most accurate way to evaluate the results of psychological treatment options in functional GI diseases. Instead, evaluation of, for instance, the general satisfaction with the treatment alternative, and evaluate if the patient can handle their symptoms better, might be a better way to assess the effectiveness of different non-pharmacological treatment alternatives. Unfortunately, such assessments were not included in our study in a formal way, which could have been useful.
The responder rate in patients receiving gut-directed hypnotherapy was 11–27% superior to the control groups. During the last decade, a number of new drugs for IBS have been developed and marketed. The effectiveness is not dramatic and the general theme has been that they are superior to placebo with about 10–15%. Some of the newer drugs for IBS have also been associated with side effects, which has led to withdrawal from the market. When comparing the responder rate to gut-directed hypnotherapy with the effect of these new and often expensive drugs, hypnotherapy seems to be at least as effective and without any known side effects. Moreover, the long-term effect of gut-directed hypnotherapy seems to be good in our study, as well as in other studies, and the cost-effectiveness is probably favorable as well.
In study 2, no significant difference between the groups regarding our primary end point, that is, change in GI-symptom severity at the 3-month follow-up relative to baseline, could be detected, even though the trends were clearly in favor of the gut-directed hypnotherapy. The reason for this is probably a type 2 error, due to relatively small number of participants. QOL improved in several domains of the IBS-QOL scale (study 1), although not significantly compared with the controls, probably also secondary to the sample size, which was clearly lower than in pharmacological studies in IBS. Small differences were also seen in QOL in study 2, but, again, a relatively small number of participants, together with the fact that SF-36 is rather insensitive to changes, may have influenced the results. Both groups in the studies were controlled until the end of the treatment phase, that is, up to 3 months. Since gut-directed hypnotherapy is available in clinical settings in Sweden, it was considered unethical to keep the controls from receiving gut-directed hypnotherapy longer than 3 months, and therefore no 1-year results were available in the control group, which has to be considered as a drawback. When performing randomized controlled trials assessing the effectiveness of psychological interventions, it is difficult to create a valid control group. In study 1, we attempted to control for attention by offering the subjects in the control group supportive and educational treatment options, whereas in study 2, the control group was just on the waiting list and no active control treatment was given. This can be considered to be a weakness in study 2, but we could not observe any obvious difference between the results in the two control groups, where one was controlled for attention, the other not. However, future studies should control for the regular prolonged interaction with the health-care providers in order to appropriately test the efficacy of gut-directed hypnotherapy in a "real world" setting.
We have evaluated gut-directed hypnotherapy as a treatment option for patients with severe IBS, given outside the highly specialized gastroenterology research centers, with a special interest in gut-directed hypnotherapy. Although the reported effects on IBS symptoms are less positive compared with some of the previous studies within this area, it seems to be an important and useful therapeutic option also in this treatment environment. The responder rate for this type of treatment is at least as good as for some of the new, expensive pharmacological treatment options. The former, and the fact that there is no known side effects makes gut-directed hypnotherapy an interesting treatment option for otherwise treatment refractory severe cases of IBS, and may also prove to be cost-effective in the long run. It now seems important to further improve cost-effectiveness, by finding predictors for a positive response in order to offer this treatment alternative to those who are most likely to respond favorably.