1. Department of Psychiatry, Leiden University Medical Center, The Netherlands
2. Rodersana Center for Addiction, Oirschot, The Netherlands
3. Center for Mental Health Care Delfland, Delft, The Netherlands
4. Department of Clinical Chemistry, Leiden University Medical Center, The Netherlands
5. Department of Neurology, Leiden University Medical Center, The Netherlands
6. Department of Psychiatry, CAPRI-University of Antwerp, Belgium