Functional Abdominal Pain Syndrome

The goal of this basic science study is to learn about the brain mechanisms of chronic pain across different chronic pain syndromes in pediatric patients. The main questions it aims to answer are: * Are there shared and distinct brain systems engaged by different forms of pediatric chronic pain? * What are predictors of recovery from chronic pain? * What brain systems are associated with the spread of pain? For this study participants will undergo: * Functional Magnetic Resonance Imaging (fMRI) * Quantitative Sensory Testing * Psychological Assessments

This is a prospective observational study collecting long-term clinical data and samples for research in pediatric inflammatory bowel disease (IBD) patients with gut inflammation and a control cohort of pediatric patients with disorders of the brain-gut interactions (DBGI) with no detectable gut inflammation.

Functional abdominal pain disorders (FAPDs) in children are common (14%) and abdominal pain has increased rapidly in children during the last ten years in Sweden. Many children with FAPDs have low quality of life, missed school days, and about 30-40% suffer from psychiatric comorbidity. FAPDs are often sustained into adulthood and a large Swedish cohort study showed that abdominal pain during childhood is an independent strong predictor anxiety and depression later in life. Internet-cognitive behavioral therapy (Internet-CBT) can improve FAPD symptoms, but a significant number of children does not respond to the treatment. We will here determine the pain regulation in children with FAPDs, compared with healthy controls, and assess: What aspects of the child's pain regulation is related to improvement for children with FAPDs engaging in Internet-CBT? Does some aspects of the child's pain regulation change during treatment?

The goal of this clinical trial is to test the effectiveness of trimebutine and probiotics in treating Functional Abdominal Pain Disorders (FAPD) in a pediatric population. The main questions it aims to answer are: Is trimebutine effective in reducing the symptoms of FAPD in children? Are probiotics effective in reducing the symptoms of FAPD in children? Participants will be randomly assigned to one of three treatment groups (trimebutine/probiotics, probiotics/placebo, or trimebutine/placebo). Undergo measurements for pain and other relevant metrics at the start of the study, after 4 weeks, and after 8 weeks. Researchers will compare the trimebutine/probiotics group to the probiotics/placebo and the trimebutine/placebo groups to see if there are significant differences in the efficacy of these treatments in reducing symptoms of FAPD in children.

The project involves researching two psychological treatments for functional abdominal pain in children. The treatments will be offered to children as an early intervention, at primary care level. The study will aim to find out if the treatments are effective and which children the different treatments are effective for.