1 Department of Psychiatry, Maastricht University Medical Centre, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. Electronic address: a.leentjens@maastrichtuniversity.nl.
2 Knowledge Institute for Medical Specialists, Utrecht, The Netherlands.
3 Department of Internal Medicine, Academic Medical Center, Amsterdam, The Netherlands; Department of Geriatrics, Gelre Hospitals, Apeldoorn, The Netherlands.
4 Department of Internal Medicine, Academic Medical Center, Amsterdam, The Netherlands.
5 Department of Old Age Psychiatry, BAVO Europoort, Rotterdam, the Netherlands.
6 OCON Orthopaedic Centre, Hengelo, The Netherlands.
7 Jeroen Bosch Hospital, 's Hertogenbosch, The Netherlands.