1. Department of Psychiatry and Psychotherapy, University Hospital Munich, Ludwig-Maximilians-University Munich, Nußbaumstr. 7, 80336 Munich, Germany
2. Department of Psychiatry and Psychotherapy, LVR University Hospital Essen, University of Duisburg-Essen, Virchowstr. 174, 45147 Essen, Germany
3. Main Institute of Addiction Research (ISFF), University of Applied Sciences Frankfurt, Nibelungenplatz 1, 60318 Frankfurt am Main, Germany
4. University of Applied Labour Studies, Seckenheimer Landstr. 16, 68163 Mannheim, Germany