1 Department of Old Age Psychiatry, South London and Maudsley NHS Foundation Trust, London; and Visiting Lecturer, Institute of Psychiatry, Psychology and Neurology, London.
2 Keele University, Honorary Professor, Queen Mary University of London; and Visiting Professor, St George's University of London.
3 Department of Primary Care and Population Health, University College London; and Emeritus Professor of Geriatric Medicine, Keele University, Keele.