1. Avon & Wiltshire Specialist Drug & Alcohol Services, Chippenham, UK
2. Psychopharmacology Unit, Social and Community Medicine, University of Bristol, Bristol, UK
3. Centre for Health Services Studies, Faculty of Social Sciences, Cornwallis North East, University of Kent, Canterbury, UK
4. Neuropsychopharmacology Unit, Imperial College London, London, UK
5. St George’s Hospital Medical School, London, UK