Geert Crombez1, Katia Wiech. 1. Department of Experimental-Clinical and Health Psychology, Henri Dunantlaan 2, B-9000 Gent, Belgium Tel.: +32 9 264 64 61, fax: +32 264 64 89. Nuffield Department of Clinical Neurosciences (Nuffield Division of Anaesthetics), FMRIB Centre University of Oxford John Radcliffe Hospital Oxford, OX3 9DU England, UK Research Group Health Psychology, University of Leuven, B-3000 Leuven, Belgium.