Intervenções cognitivo - comportamentais autoguiadas na Síndrome do intestino irritável: evidências, mecanismos psicológicos e desenvolvimento de recursos psicoterapêuticos

Abstract

Irritable bowel syndrome (IBS) is a highly prevalent disorder of the gut–brain axis, characterized by recurrent gastrointestinal symptoms and a substantial impact on quality of life, social and occupational functioning, and mental health among affected individuals. The biopsychosocial model of IBS highlights the complex interaction between biological, psychological, and social factors, requiring integrated therapeutic approaches. Among available treatments, cognitive-behavioral therapy (CBT) is widely recognized as an effective intervention with strong empirical support, capable of reducing gastrointestinal symptoms and promoting better psychological adjustment. However, limited access to specialized treatments underscores the need to develop more accessible alternatives, such as self-guided interventions. The implementation and evaluation of this treatment format, particularly when structured to address IBS-specific features such as gastrointestinal symptom-specific anxiety (GSA), represent promising strategies to reduce the negative impact of this disorder on patients’ lives and to expand access to evidence-based psychological interventions. Accordingly, this doctoral thesis aimed to: 1) identify, in the scientific literature, evidence on the effectiveness of selfguided or minimal-contact treatments for IBS; 2) investigate which psychological variables have been identified in the literature as mediators of the effect of CBT on the improvement of gastrointestinal symptoms in adults diagnosed with IBS; 3) adapt the Visceral Sensitivity Index for Brazilian Portuguese and gather validity evidence for this instrument assessing GSA; 4) develop and evaluate two booklets addressing GSA for patients with IBS, one focused on cognitive and emotional strategies and the other on exposure-based strategies; and 5) adapt and evaluate, in an international context, an English-language version of the booklet focused on cognitive and emotional strategies. Taken together, the findings of this dissertation offer theoretical, methodological, and clinical contributions. From a theoretical perspective, they strengthen our understanding of AGE as a central construct in SII and as a mechanism of change in CBT-based interventions. From a methodological perspective, the adaptation and validation of the VSI for Brazilian Portuguese expands the possibilities for the systematic assessment of AGE in the national context. At the applied level, the development and evaluation of evidence-based booklets contribute to expanding the repertoire of low-intensity psychotherapeutic interventions, with the potential for both national and international reach.