1. Centre for Health Services Studies, School of Social Science and Social Policy Research, George Allen Wing, University of Kent, Canterbury, Kent, UK
2. College of Health Sciences, Qatar University, Doha, Qatar
3. Addictions Department, National Addiction Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
4. Northumberland Tyne and Wear NHS Foundation Trust, Newcastle, UK
5. Institute of Health and Society, Newcastle University, Newcastle, UK
6. Paediatric Emergency Medicine, Imperial College London, London, UK
7. School of Health and Social Care, Teesside University, Middlesbrough, UK
8. School of Psychology, University of Surrey, Guildford, UK
9. Swansea Centre for Health Economics, College of Human and Health Sciences, Swansea University, Swansea, UK
10. University of Hull, Hull, UK
11. Swansea University Medical School, Swansea, UK