1. Addictions Department, National Addiction Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
2. Centre for Health Services Studies, University of Kent, Canterbury, UK
3. Department of Public Health, College of Health Sciences, Qatar University, Qatar
4. Northumberland Tyne and Wear NHS Foundation Trust, Newcastle upon Tyne, UK
5. Institute of Health and Society, Newcastle University, Newcastle upon Tyne, 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. Institute for Clinical and Applied Health Research, University of Hull, Hull, UK
11. Medical School, Swansea University, Swansea, UK
12. South London and Maudsley NHS Foundation Trust, London, UK