1. University Hospital Groningen; Department of Psychiatry; P.O. Box 30001 Groningen Netherlands 9700 RB
2. University of Groningen; Department of Psychiatry (k 5.21), Rob Giel Research Centre; WHO Collaborating Center, Academisch Ziekenhuis Hanzeplein I, P.O. Box 30.001 Groningen Netherlands 9700 RB
3. University Medical Centre Groningen; Groningen Netherlands