1. Psychology Department, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
2. Wessex Neurological Centre, Southampton General Hospital, Southampton, UK
3. National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
4. Department of Psychological Medicine, Royal Free Hospital, London, UK
5. Department of Psychiatry, University of Hong Kong, Hong Kong
6. Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK