1. MRC Integrative Epidemiology Unit; University of Bristol; Bristol UK
2. UK Centre for Tobacco and Alcohol Studies; University of Bristol; Bristol UK
3. School of Experimental Psychology; University of Bristol; Bristol UK
4. School of Social and Community Medicine; University of Bristol; Bristol UK
5. MRC Centre for Neuropsychiatric Genetics and Genomics; Cardiff and University; Cardiff UK
6. Wellcome Trust Centre for Human Genetics; University of Oxford; Oxford UK