1. Department of Psychiatry; Leiden University Medical Center; Leiden 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; Leiden The Netherlands
5. Department of Neurology; Leiden University Medical Center; Leiden The Netherlands
6. Department of Psychiatry; CAPRI-University of Antwerp; Antwerp Belgium