1. School of Psychology, College of Social Science, University of Lincoln, Lincoln, UK
2. School of Health and Social Care, College of Social Science, University of Lincoln, Lincoln, UK
3. National Addictions Centre, Kings College London, London, UK
4. Peninsula Technology Assessment Group, College of Medicine and Health, University of Exeter, Exeter, UK
5. Department of Psychiatry, University of Melbourne, Carlton, Australia
6. Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK