1 MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, DeCrespigny Park, London, SE5 8AF, UK.
2 Division of Behavioral Genetics, Rhode Island Hospital, Providence, RI, USA.
3 Department of Psychiatry & Human Behavior, Warren Alpert Medical School, Brown University, Providence, RI, USA.
4 Department of Psychology, The Pennsylvania State University, State College, PA, USA.
5 Institute for Behavioral Genetics, University of Colorado, Boulder, CO, USA.
6 MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, King's College London, DeCrespigny Park, London, SE5 8AF, UK. robert.plomin@kcl.ac.uk.