1 Jurrijn A. Koelen, University of Leuven, Tiensestraat 102, 3000 Leuven, Belgium. Email: jurkoel@gmail.com; Allan Abbass, Departments of Psychiatry and Psychology, Dalhousie University, Halifax, Canada; Jan H. Houtveen, Rinie Geenen, Department of Clinical and Health Psychology, Utrecht University, Utrecht, The Netherlands.