1. Health Economics and Decision Science (HEDS), School of Health and Related Research, (ScHARR); University of Sheffield; Sheffield UK
2. Section of Public Health, School of Health and Related Research (ScHARR); University of Sheffield; Sheffield UK
3. Injecting Drug Use Team, HIV and STI Department, Centre for Infectious Disease, Surveillance and Control; Public Health UK (PHE); London UK
4. Centre for the Economics of Mental and Physical Health; King's College London; London UK
5. National Addiction Centre, Addictions Department, Institute of Psychiatry, Psychology and Neuroscience; King's College London; London UK
6. Department of Biostatistics; King's College London; London UK
7. Department of Mental Health, Social Work and Integrative Medicine; Middlesex University; Hendon UK