Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by abdominal pain or discomfort, or both (Longstreth et al., 2006). According to the Rome Ⅳ criteria, the latest diagnostic criteria for IBS, the prevalence rate of IBS in Japan is approximately 2.2% (ranging from 1.6–2.7%; Sperber et al., 2021). The diverse symptoms of IBS, which can range from mild to severe, are bothersome and associated with high medical costs and low work efficacy (Drossman et al., 2011; Faresjö et al., 2019; Nellesen et al., 2013). Some can live out their lives normally and experience symptoms only in specific situations, for example, while commuting to school in a crowded train in the morning, before a presentation, or during a meeting. Others cannot tolerate their pain and consequently miss work (Buono et al., 2017). Moreover, the more severe the symptoms, the higher the comorbidities, such as anxiety and depression, leading to lower quality of life (QOL; Lackner et al., 2014). Patients with IBS are classified into four subtypes based on their predominant stool patterns: constipation-predominant (IBS-C), diarrhea-predominant (IBS-D), mixture of constipation and diarrhea (IBS-M), and unclassified (Longstreth et al., 2006). A potential reason for this diversity is the corresponding variety of psychological features (van Tilburg et al., 2013), such as symptom-specific cognition, avoidance behaviors, and gastrointestinal safety behaviors (Sugaya et al., 2012; Windgassen, Moss-Morris, Goldsmith, et al., 2019).
Japanese treatment guidelines for IBS recommend three steps: diet therapy and lifestyle modifications, gut targeted psychopharmacological therapy, and specific psychotherapy (Fukudo et al., 2021). Cognitive behavioral therapy (CBT) is the most effective form of specific psychotherapy with long-term efficacy in alleviating IBS symptoms (Black et al., 2020). Studies have elucidated the mechanisms behind the effectiveness of CBT for IBS (Windgassen et al., 2017) and established that symptom-specific cognition could be a possible factor in exacerbating IBS symptoms (Windgassen, Moss-Morris, Goldsmith, et al., 2019). Recently, Internet-based CBT (ICBT) has been developed, constituting the provision of CBT via email and other online means, and its efficacy as a cost-effective method in relieving IBS has been tested (Sampaio et al., 2019). Additionally, Ljótsson et al. (2010) and Ljótsson et al. (2011) showed that ICBT was more effective in alleviating IBS symptoms for participants in the treatment group as compared to those in the control condition.
However, a considerable number of people with IBS symptoms remain undiagnosed by gastroenterologists even though their symptoms meet the criteria (Ringström et al., 2007). Known as “non-patients with IBS,” they exist on a psychosocial continuum between patients and normal individuals (Drossman et al., 1988). However, the symptoms that non-patients experience are not significantly different from IBS patients’, and they suffer from severe pain as well. Fujii and Nomura (2008) showed that approximately 30% of IBS non-patients may become IBS patients within a timeframe as early as three years after experiencing symptoms. Some possible reasons for not seeking a diagnosis include not perceiving bowel symptoms as an illness that requires medical care, having insufficient information about effective treatments for IBS, availability of CBT only in specific centers in Japan, and long waiting lists to see specialists. Moreover, CBT has not been attempted for non-patients with IBS because psychotherapy has been established as the third step of the treatment process or adapted for refractory patients (individuals with IBS who do not respond to pharmacological treatments after 12 months) and those who develop chronic symptoms (NICE, 2015). Further, there is insufficient data to optimize clinical trials because no treatment has been developed for non-patients.
Endo (2007) and Endo et al. (2010) studied children and adolescents in Japan and reported that none of the students in their study had been diagnosed with IBS or received treatment even though the onset of IBS often occurs at a young age (Yamamoto et al., 2015). Moreover, according to a study of pediatrician visits in Japan, many patients who complained about IBS symptoms were associated with school absenteeism and experienced difficulty in going out (Fujii et al., 2021). Thus, treatment methods that consider psychosocial factors unique to Japan need to be established.
The purpose of this study was to address the problems experienced by IBS non-patients in Japan—the low accessibility of CBT and inadequacy of treatment options available. Additionally, there is room to strengthen the effect of ICBT interventions for IBS, which involve an automatic message system, visualization of data, and assistance with homework related to the treatment. Given this context, using a mobile application appears to be the most suitable approach. Accordingly, we developed a mobile application for non-patients with IBS, which has higher accessibility than the conventional methods of providing CBT.
Moreover, CBT for IBS usually includes multiple treatment modalities that lead to longer treatment durations and higher costs. Hence, we focus on symptom-specific cognition as the exacerbation factor; to the best of our knowledge, this is a novel aspect of our intervention for IBS. The application used included original cognitive restructuring strategies to ease the comprehension of CBT, psychoeducation, and exposure, which are also in line with previous studies (Kawanishi et al., 2019).