Introduction

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders. Since its prevalence in the general population is as high as 5–10% [1], its associated medical and economic problems have also been pointed out [2]. The Rome IV criteria [3], the diagnostic criteria currently used internationally, defines IBS as recurrent abdominal pain occurring on an average, at least 1 day per week in the last 3 months, and associated with at least two of the following three abnormalities: (1) defecation-related, (2) change in defecation frequency, or (3) change in stool characteristics (appearance). The pathogenesis of IBS includes: (1) abnormalities in gastrointestinal motility, (2) lowered gastrointestinal sensory threshold, and (3) psychological abnormalities (anxiety, depression, etc.). The pathophysiology of IBS includes: (1) abnormalities in gastrointestinal motility, (2) decreased gastrointestinal sensory threshold, and (3) psychological abnormalities (anxiety, depression, etc.), all of which, are related to abnormalities in the functional relationship between the brain and intestine (brain-gut connection). Since IBS is a gastrointestinal psychosomatic disorder that often develops and worsens with stress, it is important to treat it from both the physical and mental aspects [4]. We shall review recent research on cognitive-behavioral therapy—one of the most widely studied psychological treatments for IBS.

Application of cognitive behavioral therapy for IBS

Guidelines for the treatment of IBS [4] recommend psychological interventions for patients, who do not respond to standard pharmacotherapy. Psychological interventions, such as cognitive behavioral therapy (CBT), relaxation, hypnotherapy, and dynamic psychotherapy have been reported to be effective for treating IBS [5]. Since it has been reported that cognitions and behaviors associated with IBS symptoms are involved in unpleasant emotions, such as anxiety and abdominal symptoms [6, 7], CBT targeting cognitions and behaviors associated with such symptoms have been widely tested for efficacy. Toner et al. [8] stated that the purpose of CBT in IBS is to reconfigure how IBS is viewed, given that, its purpose is to help patients to: (1) reframe their view of IBS from helplessness and hopelessness to resourcefulness and hopefulness, (2) identify the relationship between their thoughts, feelings, and behaviors with the environment and IBS symptoms, and (3) identify and implement more effective coping strategies to improve the quality of life (QOL). A recent meta-analysis reported that IBS patients’ pretreatment cognitive-emotional characteristics (comorbidity of mood or anxiety disorder, symptom catastrophizing and worries, tendencies of somatosensory amplification, low symptom acceptance, or self-efficacy) predict bad patient outcomes in CBT [9].

Various forms of CBT for IBS

CBT for IBS focuses on addressing the cognitions and behaviors associated with IBS symptoms and combines diverse content, such as cognitive techniques, exposure, stress management, and mindfulness, the effects of which, have been widely studied. For example, CBT for IBS conducted in a previous study by Lackner et al. [10] consisted of the provision of information regarding brain-gut interactions; self-monitoring of gastrointestinal symptoms, their antecedents (i.e., triggers) and consequences; muscle relaxation to dampen physiological arousal and increase control over gastrointestinal symptoms; worry control to challenge and dispute negatively skewed thinking patterns; flexible problem solving to aid in the deployment of more effective ways of managing realistic stressors; and relapse prevention training to maintain treatment gains. In addition, CBT combined with exposure has been reported to be effective, especially in patients with significant avoidance behaviors related to IBS symptoms [11]. Several studies have also demonstrated the effectiveness of CBT combined with mindfulness [12], and the addition of exposure has been reported to increase IBS symptoms and related anxiety as well as QOL improvements [13]. Recently, several studies have demonstrated the efficacy of CBT with interoceptive exposure in IBS patients [14, 15]. Interoceptive exposure involves exposing one’s self to self-induced abdominal sensations (e.g., tightening abdominal muscles, consuming foods that are to be avoided, etc.) to reduce anxiety in response to abdominal disturbance common in IBS [15].

Research on CBT for IBS varies not only in terms of the interventions’ contents, but also in terms of its implementation (individual or group, face-to-face or online). Research on internet-delivered CBT has been increasing in recent years (Table 1), and its effects on IBS and functional abdominal pain have been seen not only in adults, but also in children [16,17,18,19]. CBT delivered through the telephone and internet has been shown to be effective, suggesting the usefulness of conducting it remotely [20]. Furthermore, internet-delivered CBT has been reported to be effective not only in improving abdominal pain, QOL, and psychological symptoms, but also in reducing health care costs [18], and is expected to become more widespread in the future. Home and clinic-based CBT have been reported to result in substantial and enduring relief of multiple IBS symptoms for patients with treatment-refractory IBS, and its effects generally extended post treatment, for a 12-month period [10]. CBT with minimal medical visits has also been shown to be cost-effective [21]. Therefore, if CBT—conducted at home via the internet or other means, as well at medical institutions—becomes widespread, it may make it easier for IBS patients, who have difficulty visiting medical institutions frequently to access appropriate and cost-effective treatments. With the use of internet or telephone-delivered CBT, however, we should be prepared with countermeasures if symptoms worsen. For example, for a child patient, a guardian should accompany and then monitor the child closely. A hotline should be set up in case of emergency.

Table 1 Recent research on the effect of internet-delivered CBT for IBS patients
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Psychological assessment tools of CBT for IBS

Psychological interventions to alter cognition and behaviors specific to IBS, require appropriate psychological assessment. Some of the scales commonly used in recent research on CBT for IBS are presented below.

Visceral sensitivity index

The Visceral Sensitivity Index is a unidimensional 15-item scale that measures gastrointestinal symptom–specific anxiety (e.g., “I often fear that I will not be able to have normal bowel movements”) [22]. Items are rated on a Likert scale ranging from 0 (strongly disagree) to 5 (strongly agree). It has a high internal consistency (Cronbach’s α = 0.93) [23]. Its qualitative score was classified as: 0–10 (minimal or mild), 11–30 (moderate), and 31–75 (severe).

Cognitive scale for functional bowel disorder

The Cognitive Scale for Functional Bowel Disorder [8] includes 25 items that measure maladaptive cognition related to abdominal symptoms (e.g., “I am always sick with bowel problems”). The items are rated from 1 (strongly disagree) to 7 (strongly agree). Its total score ranges from 25 to 175, and it has a high internal consistency (Cronbach’s α = 0.93).

Gastrointestinal cognitions questionnaire

The Gastrointestinal Cognitions Questionnaire consists of 16 self-report items rated on a 5-point Likert scale, ranging from 0 (hardly) to 4 (very much). Individual items are summed, and the total scores range from 0 to 64. The questionnaire consists of three subscales: the pain/life interference subscale (e.g., “When I feel my GI symptoms acting up, I am afraid the pain will be excruciating and intolerable”), the social anxiety subscale (e.g., “If I have to get up and leave an event, meeting, or social gathering, to go to the bathroom, people will think there is something wrong with me”), and the disgust sensitivity subscale (e.g., “The thought of fecal incontinence is terrifying. If it happened, it would be awful”). The scale has been shown to have good internal consistency (Cronbach’s α = 0.92) [24]. Its qualitative score was classified as: 0–19 (minimal or mild), 20–39 (moderate), and 40–64 (severe).

Irritable bowel syndrome-behavioral responses questionnaire

The Irritable Bowel Syndrome-Behavioral Responses Questionnaire [25] includes 26 items with responses ranging from 1 (never) to 7 (always), and its total score ranges from 26 to 182. It consists of two factors: avoidance behavior scale (e.g., “I avoid going out in case I have problems with my IBS”) and control behavior scale (e.g., “After opening my bowels, I check my stool for abnormalities”), and has sufficient internal consistency (Cronbach’s α = 0.86).

The irritable bowel syndrome quality of life questionnaire

The Irritable Bowel Syndrome Quality of Life questionnaire is a 34-item self-report measure, specifically designed to assess the impact of IBS on QOL (e.g., “I am bothered by how much time I spend on the toilet”) [26, 27]. It has a high internal consistency (Cronbach’s α = 0.95) [27]. Its qualitative score was classified as: 0–31 (minimal or mild), 32–66 (moderate), and 67–100 (severe impairment).

The effect of CBT for IBS and its psychobiological mechanism

A number of previous studies have demonstrated that CBT improves anxiety, depression, QOL, and abdominal symptoms in patients with IBS [28,29,30]. It has also been reported that CBT reduces neural activity in the parahippocampal gyrus and lower right cingulate cortex, and that changes in limbic activity are associated with improvements in abdominal symptoms and anxiety [31]. These brain regions are associated with excessive vigilance and emotional memory [32]. Some previous studies reported that CBT has a direct effect on IBS symptoms, that were independent of its effect on psychological distress, suggesting that the reduction of IBS symptoms improve psychological distress, rather than vice versa [33]. Furthermore, a meta-analysis of CBT for IBS reported more efficacy for abdominal symptoms rather than psychological symptoms [30]. In other words, it is interesting to note, that cognitive and behavioral transformation in IBS may contribute to the improvement of abdominal symptoms through direct involvement in the brain-gut correlation process of IBS, and thus alleviate psychological distress, such as anxiety and depression.

Conclusion

We reviewed recent research on the characteristics and effects of CBT for IBS, its mechanism, and tools for measuring its effectiveness. The biopsychological mechanisms underlying the effects of CBT have been gradually elucidated in parallel with the elucidation of the biological characteristics of IBS. In addition, internet-delivered CBT has recently shown the possibility of providing more accessible and cost-effective psychological interventions to IBS patients, in formats other than face-to-face. These tools are expected to spread to many IBS patients, including those, suffering from IBS, but who do not visit medical institutions.