JJW is supported by a Post-Doctoral Research Fellowship from the Oak Foundation (http://www.oakfnd.org/). JJW, GH, LP, NT, GDS and MRM are members of the Medical Research Council (MRC) Integrative Epidemiology Unit: support from the MRC is gratefully acknowledged (MC_UU_12013/6). JJW and MRM are members of the UK Centre for Tobacco and Alcohol Studies, a UK Clinical Research Council Public Health Research: Centre of Excellence. Funding from British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council, and the National Institute for Health Research, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged. XC, JC and REP acknowledge support from the National Institute on Drug Abuse (NIDA) (R01DA032246). REP also acknowledges support from NIDA (R25 DA26119) and National Institute of Mental Health (NIMH) (T32 MH20030). AIS is supported by a Wellcome Trust 4-year PhD studentship in molecular, genetic, and lifecourse epidemiology (WT083431MA). LP is funded by a UK MRC Population Health Scientist fellowship (MR/J012165/1). VS was funded by the Academy of Finland (139635) and the Finnish Foundation for Cardiovascular Research. RJR acknowledges support from
