Group cognitive behavioural therapy (GCBT) versus treatment as usual (TAU) in the treatment of irritable bowel syndrome (IBS): a study protocol for a randomized controlled trial

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder characterized by chronic or recurrent abdominal pain and altered bowel habits [1]. Its prevalence among the world population is as high as 10–15%, and IBS is a global health problem [2]. Although IBS is non-fatal, the symptoms affect quality of life (QOL) and social functioning [3] and lead to a health-care burden [4, 5]. Additionally, IBS typically develop in younger adulthood, an important period for education and career development. Thus, the corresponding socioeconomic impact of IBS is considerable [6].

However, there is no gold-standard therapy for IBS, and few options exist for patients who do not respond to available pharmacotherapies. Some psychotherapies, including cognitive behavioural therapy (CBT), hypnotherapy, and stress management therapy, have been proposed for IBS [7, 8]. In particular, CBT for IBS has been studied extensively and a systematic review has estimated the number needed to treat to be approximately 3 [95% CI, 2 to 6] [7]. Also, CBT is recommended in several international guidelines for IBS [9, 10].

Among the several programs reported as CBT for IBS, we focused on the interoceptive exposure-based CBT (CBT-IE) program [11]. CBT-IE was originally developed for panic disorder [12]. Patients with panic disorder are fearful of the sensations that are similar to those that they experience during their panic attacks, and tend to avoid the behaviours and activities that may cause them [13, 14]. These anxieties increase hypervigilance on somatic sensations and are linked to catastrophic thinking [15]. Consequently, even mild somatic sensations produce anxiety and the resultant anxiety intensifies the somatic sensations, thus creating a vicious circle of anxiety and somatic sensations [16]. These interactions between visceral anxiety and somatic sensations are very similar to those observed in patients with IBS [11, 16]. IBS patients show hypervigilance and hypersensitivity to visceral sensations, such as increased intensity of sensations and lowered thresholds for visceral pain [17, 18]. IBS patients often have exaggerated beliefs and anxiety about their symptoms, which make them consciously or unconsciously avoid situations causing the symptoms. Such avoidant behaviours may then increase anxiety, creating a vicious cycle of symptom exacerbation. Thus, CBT-IE approaches that target visceral anxiety using methods similar to those for panic disorder may be suited for IBS [11].

CBT-IE for IBS therefore includes exposure to visceral sensations, in addition to traditional CBT (such as psychoeducation, self-monitoring, cognitive reconstruction, attention training, and in vivo exposure) [11]. In the program, participants are encouraged to experience self-induced visceral sensations (eg, by putting ice on their abdomen) to reduce visceral anxiety. Such bidirectional interaction between somatic sensation and visceral anxiety is consistent with the concept of the brain-gut axis, which is considered to be the mechanism of IBS [19]. Thus, through the use of CBT-IE for IBS, we may be able to provide new insights into the brain-gut axis, a mechanism that plays an important role in the development and maintenance of IBS.

However, access to CBT for patients with IBS is limited due to the paucity of trained therapists, the lengthy time requirements for both the therapists and the patients, and the associated costs [20]. Given the large number of IBS patients and growing health care and social burden, it seems worthwhile to establish the effectiveness of the IBS Group CBT (GCBT). GCBT has been found to be effective in depression, panic disorder and other psychiatric disorders [21], and is attractive since it is cost and time effective [22].

Little is known about the effect of CBT-IE for IBS patients on a group basis. We will conduct a randomized controlled trial (RCT) to examine the efficacy of GCBT for IBS and this study will provide new insights into GCBT for IBS. Our programme aims to break the vicious cycle between anxiety, attention, avoidance behaviour, visceral sensations and disease severity. We will compare GCBT plus treatment as usual (TAU) against TAU alone. Our co-primary outcomes include disease-specific QOL and symptom severity of IBS at week 13 which is 1 month after the end of treatment.

The study is a two-arm (allocation ratio 1:1), parallel group, waiting-list controlled, open label, stratified block randomized superiority trial. The reporting of this study protocol follows the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) guideline [23] and the recent reporting guideline for interventions [24]. The study will be conducted in accordance with the Japanese Ethical Guidelines for Medical and Health Research Involving Human Subjects (December 22, 2014) and its guidance (revised February 28, 2017).

We have described the RCT protocol of GCBT with interoceptive exposure for IBS patients. The primary objective of this study is to evaluate the effectiveness of GCBT for IBS and contribute to the provision of a scientific basis for non-pharmacotherapy to treat refractory IBS. The study also has several secondary objectives, such as changes in anxiety and depression.

Group therapies are cost and time effective. In addition, group therapy has the advantage of allowing participants to interact with others with similar problems and are expected to have mutual support capabilities through sharing experiences and coping models in difficult situations among themselves [47, 48]. However, only a few randomized controlled trials (RCTs) of GCBT for IBS have been reported, and the IBS diagnostic criteria, control groups, and outcome measures used in each study were different. Moreover, two of the studies were small [49, 50], and one of them reported inappropriate randomization [49]. About the effectiveness of GCBT for IBS, their findings have been mixed [49‐51]. Two RCTs confirmed the effect of GCBT for IBS; one study enrolled 47 IBS participants (diagnostic criteria by researchers) and found that GCBT was superior to the waiting-list group in alleviating abdominal complaints at 3 months [49]; another study randomized 23 IBS patients (Rome criteria) and found that GCBT produced greater reduction in gastrointestinal symptoms at 3 months than the home-based symptom monitoring with weekly telephone contact [50]. In contrast, a third study concluded that GCBT is not superior to an attention placebo control condition. The last study enrolled 210 IBS patients (Rome II criteria) and studied the effects of GCBT versus psychoeducational support versus intensive symptom and daily stress monitoring, on patients’ GI symptom for 3 months [51]: Both GCBT and psychoeducational support were significantly more effective than intensive symptom monitoring, but GCBT and psychoeducational support group did not differ.

The salient features of our CBT program include: (i) addition of interoceptive exposure; (ii) removal of relaxation training; and (iii) use of the treatment manual. CBT-IE was developed using CBT for panic disorder as a model, aiming to correct excessive visceral anxiety and avoidance behaviour through cognitive restructuring and repeated exposures to somatic sensations [11]. Many psychotherapies for IBS include stress management with relaxation training. However, recent studies showed that reducing anxiety and avoidance behavior through interoceptive exposure resulted in higher quality of life than reducing stress responsiveness to daily life through relaxation training. We therefore dropped relaxation training from CBT-IE for IBS [11].

Also, few therapists, either clinical psychologist, psychiatrist or gastroenterologist, have experience with CBT for physical diseases such as IBS in Japan. The therapists of this RCT have therefore had little experience with CBT for physical diseases and will conduct therapies after brief but intensive training based on the manual. We consider that GCBT for IBS can be more widely practiced, if it can be effectively conducted by less skilled therapists using the manual.