1. Salvation Army Centre for Addiction Services and Research, Faculty of Social Sciences, University of Stirling, Stirling, UK
2. School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, UK
3. Fife Pain Management Service, NHS Fife, Kirkcaldy, UK
4. Population and Behavioural Science Division, School of Medicine, University of St Andrews, St Andrews, UK
5. NHS Addiction Services, NHS Fife, Kirkcaldy, UK