1 Elliott Rees, MRes, James T. R. Walters, PhD, MRCPsych, Michael J. Owen, PhD, FRCPsych, George Kirov, PhD, MRCPsych, Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK. Email: kirov@cardiff.ac.uk.