1. Mental Health Sciences Unit, University College London, London, UK
2. Camden and Islington NHS Foundation Trust, London, UK
3. Centre for Outcomes Research and Effectiveness, University College London, London, UK
4. Institute of Neurology, University College London, London, UK
5. National Addiction Centre, Institute of Psychiatry, King’s College London, London, UK
6. Unit of Social and Community Psychiatry, Queen Mary University of London, London, UK