1. Mortimer Market Centre, Central and North West London NHS Foundation Trust, London, United Kingdom.
2. National Addiction Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.
3. Queen Elizabeth The Queen Mother Hospital, East Kent Hospitals University NHS Foundation Trust, Margate, United Kingdom.
4. Glasgow Royal Infirmary, NHS Greater Glasgow and Clyde, Glasgow, United Kingdom.
5. UCL Medical School, University College London, London, United Kingdom.
6. Chelsea and Westminster NHS Foundation Trust, London, United Kingdom.
7. UCL Division of Psychiatry, University College London, London, United Kingdom.
8. Camden and Islington NHS Foundation Trust, London, United Kingdom.