1. Marie Curie Palliative Care Research Department , Division of Psychiatry, , London , UK
2. University College London , Division of Psychiatry, , London , UK
3. Department of Psychiatry , Faculty of Medicine, , Hat Yai , Thailand
4. Prince of Songkla University , Faculty of Medicine, , Hat Yai , Thailand
5. Centre for Ageing Population Studies , Research Department of Primary Care and Population Health, , London , UK
6. University College London , Research Department of Primary Care and Population Health, , London , UK
7. Department of Psychological Medicine, Royal London Hospital, East London NHS Foundation Trust , London , UK