Jan Dirk Blom1, Iris E C Sommer2, Sanne Koops2, Oliver W Sacks3. 1. Parnassia Psychiatric Institute, The Hague, The Netherlands; Department of Psychiatry, University of Groningen, Groningen, The Netherlands. Electronic address: jd.blom@parnassia.nl. 2. Department of Psychiatry, University Medical Centre Utrecht, Utrecht, The Netherlands; Rudolf Magnus Institute for Neuroscience, Utrecht, The Netherlands. 3. New York University School of Medicine, New York, USA.