1. Department of Child and Adolescent Psychiatry/Psychology; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
2. Department of Paediatric Gastroenterology; Erasmus MC-Sophia Children's Hospital; Rotterdam The Netherlands
3. Department of Psychiatry; University of Pittsburgh; Pittsburgh PA USA
4. Research Institute of Child Development and Education; University of Amsterdam; Amsterdam The Netherlands
5. Academic Center for Child Psychiatry the Bascule/Department of Child and Adolescent Psychiatry; Academic Medical Center; Amsterdam The Netherlands