Jonathan Williams is a Consultant Child and Adolescent Psychiatrist at Barnet Enfield and Haringey Mental Health Trust, and an Honorary Research Associate at the Department of Clinical Education and Health Psychology of University College London. He has worked as Honorary Consultant in Great Ormond Street Hospital, London, and did research at the Centre for Advanced Study, Oslo. Peter Hill is an Emeritus Professor at the University of London and an Independent Consultant in Child and Adolescent Psychiatry. He was foundation professor of child mental health in the University of London at St George's Hospital and has had numerous national and international roles including Chair of the Faculty of Child and Adolescent Psychiatry of the Royal College of Psychiatrists, and President of the European UEMS Specialist Section of Child and Adolescent Psychiatry.