1. 1National Addiction Centre, Institute of Psychiatry, King’s College London, Addiction Sciences Building, 4 Windsor Walk, Denmark Hill, London SE5 8AF, UK
2. 2South London and Maudsley NHS Foundation Trust, London, UK
3. 3Senior Clinical Lecturer in Addiction Psychiatry, National Addiction Centre, Institute of Psychiatry, King’s College London, Addiction Sciences Building, 4 Windsor Walk, Denmark Hill, London SE5 8AF, UK
4. 4Department of Psychiatry, Birmingham and Solihull Mental Health NHS Foundation Trust, The Barberry, 25 Vincent Drive, Edgbaston, Birmingham B15 2FG, UK
5. 5Senior Clinical Research Fellow, National Addiction Centre, Institute of Psychiatry, King’s College London, Addiction Sciences Building, 4 Windsor Walk, Denmark Hill, London SE5 8BB, UK ;
6. 6South London and Maudsley NHS Foundation Trust, Community Drug and Alcohol Team, Lorraine Hewitt House, 12-14 Brighton Terrace, Brixton London SW9 8DG, UK
7. 7National Addiction Centre, Institute of Psychiatry, King’s College London, Addiction Sciences Building, 4 Windsor Walk, Denmark Hill, London SE5 8BB, UK