Abdominal pain is a common symptom in patients with inflammatory bowel disease (IBD). Up to 70 % of IBD patients experience pain when the disease is active. Even when patients with IBD are in remission, 20-50 % experience ongoing pain. The precise mechanism of developing chronic abdominal pain in patients with IBD in remission remains unknown. The aim of this study is to identify psychophysiological and biological risk factors for the development of chronic abdominal pain in patients with newly diagnosed IBD (ulcerative colitis and Crohn's disease). This study consists of 4 sections (Study 1A, 1B, 2, and 3): Study 1A: We perform a longitudinal study in 150 patients with new-onset IBD over 18 months to identify risk factors related to the brain-gut axis for the development of chronic pain. This is a collaborative study with IBD BioResourse Inception study. We administer online questionnaires, collect stool and blood samples, and record heart rate. Other physiological data collected by the Inception study will be also used for the analysis. Study 1B: This is also a collaborative study with the Inception study. We will apply for our detailed questionnaires for 7 days (as per study 1A) to be administered to all the new patients (n=450) that are included in the Inception study on a voluntary basis. Patients will be followed for 12 months. Study 2 and 3: Study 2 and 3 are a questionnaire-based cross-sectional study in patients with IBD. The participants for study 2 are patients registered in IBD BOOST study and those for study 3 are patients registered in IBD BioResource (but not in IBD Boost study). Detailed online questionnaires will be administered to them. These studies are just one-day assessment.