1. Centre for Psychiatry, Barts and the London School of Medicine, Queen Mary University of London, London, United Kingdom
2. Department of Social and Environmental Health Research, London School of Hygiene and Tropical Medicine, London, United Kingdom
3. Centre for Primary Care and Public Health, Barts and the London School of Medicine, Queen Mary University of London, London, United Kingdom
4. School of Psychology, University of Surrey, Guildford, United Kingdom