1. Department of Developmental Psychiatry, University of Cambridge, Cambridge, UK
2. Office for National Statistics, Newport, Wales, UK
3. Health Policy (SM) and Health and Biomedical (KS), National Centre for Social Research, London, UK
4. Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
5. Institute of Health Research, University of Exeter Medical School, Exeter, UK
6. NHS Digital, London, UK