1. Department of Medical and Clinical Psychology, Tilburg University , PO Box 90153, 5000 LE Tilburg , The Netherlands
2. Scientific Research Department, Helen Dowling Institute , Professor Bronkhorstlaan 20, 3723 MB Bilthoven , The Netherlands
3. Department of Methodology and Statistics, Tilburg University , PO Box 90153, 5000 LE Tilburg , The Netherlands
4. Admiraal de Ruyter Hospital (Adrz) , PO Box 15, 4460 AA Goes , The Netherlands