1. UK Centre for Tobacco &and Alcohol Studies, Division of Epidemiology and Public Health; University of Nottingham; Nottingham NG5 1PB UK
2. UK Centre for Tobacco and Alcohol Studies and NIHR School for Primary Care Research, Division of Primary Care; University of Nottingham; Nottingham NG7 2UH UK
3. UK Centre for Tobacco and Alcohol Studies, Addictions Department; Institute of Psychiatry King's College London; SE5 8AF UK