[1] Department of Psychology,
[2] St. George’s Hospital Medical School,undefined
[3] Cranmer Terrace,undefined
[4] London SW17 0RE,undefined
[5] UK e-mail: asteptoe@sghms.ac.uk,undefined
[6] Fax: +44-181-767-2741,undefined
[7] Health Behaviour Unit,undefined
[8] Department of Epidemiology and Public Health,undefined
[9] University College London,undefined
[10] 2–17 Torrington Place,undefined
[11] London WC1E 6BT,undefined
[12] UK,undefined