Internet-delivered Exposure-based Cognitive Behavior Therapy for Adolescents with Functional Abdominal Pain disorders

Sammanfattning: Background: Irritable bowel syndrome (IBS), functional abdominal pain (FAP), and functional dyspepsia (FD) belong to the functional abdominal pain disorders, and are common in adolescents all over the world. Adolescents with IBS, FAP or FD often report anxiety, depression, school absenteeism, and a quality of life as low as children with inflammatory bowel diseases. The treatment effects from pharmacological or dietary treatments are unsatisfactory for this age group, while cognitive behavioral therapies (CBT) have shown some promising effects. However, CBT is rarely available as there are very few CBT-therapists trained in functional abdominal pain disorders. For adult IBS, exposure-based internet-delivered CBT (Internet-CBT) has been very successful, but this kind of treatment has neither been evaluated for adolescent IBS, nor adapted to the age group. Aims: The overall aim of this thesis was to develop an effective and easily accessible treatment for adolescents with functional abdominal pain disorders. Specific aims were to investigate: ° The feasibility and potential efficacy of exposure-based Internet-CBT for adolescents with IBS, FAP or FD (Study I). ° The efficacy of exposure-based Internet-CBT for adolescents with IBS (Study II). ° Mechanisms of change in exposure-based Internet-CBT for adolescents with IBS (Study III). ° The feasibility and potential efficacy of a tailored exposure-based Internet-CBT for adolescents with FAP or FD (Study IV). Methods: The feasibility and potential efficacy of the treatment were evaluated in an open pilot including adolescents (age 13-17) with IBS, FAP or FD (Study I). The efficacy of the treatment for adolescents with IBS was tested in a randomized controlled trial (RCT) with a wait-list control (Study II). Treatment mechanisms were investigated on data from the RCT, through analysis of change during treatment of two proposed mediators (perceived stress and avoidant behavior), and primary outcome (global gastrointestinal symptoms) (Study III). Lastly, the feasibility and potential efficacy of the treatment, when tailored specifically for functional abdominal pain and functional dyspepsia, were evaluated in an open pilot (Study IV). All trials had somatic symptoms as primary outcome, global gastrointestinal symptoms in Study I-III, and pain intensity in Study IV. Assessments were made at pretreatment, posttreatment, and at 6-month follow-up (Study I-II and IV). In the RCT weekly assessments were included in the analyses (Study II). In Study IV, the follow-up assessments 6 months after treatment are still ongoing, and will therefore not be presented in the thesis. Results: In the first pilot treatment adherence was high, and the improvements were significant and moderately sized, with a stable treatment effect after 6 months (Study I). The RCT showed significant improvement on all relevant outcomes in favor of the treatment with small to moderate effect sizes, which were stable or significantly improved 6 months after treatment conclusion (Study II). The analysis of mediators showed that reduction in avoidant behavior, but not reduction in perceived stress, predicted improvement in gastrointestinal symptoms due to treatment (Study III). The open pilot for FAP and FD showed significant improvement with strong effect sizes on all relevant outcomes, from pretreatment to posttreatment (Study IV). Conclusion: Exposure-based Internet-CBT is a feasible and effective treatment for adolescent IBS. Feasibility and potential treatment effects may be increased with a tailored treatment for FAP and FD. Our results suggest that, it is by reducing avoidant behavior that gastrointestinal symptoms improve during exposure-based Internet-CBT, while a reduction in stress is not a necessary target in treatment.