1. Center for Interdisciplinary Addiction Research of Hamburg University, Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
2. Institute of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
3. Clinical Psychology and Psychotherapy, Institute of Psychology, Faculty of Psychology and Movement Sciences, Universität Hamburg, Hamburg, Germany
4. Department of Psychiatry and Psychotherapy, Paracelsus Medical University, Nuremberg, Germany
5. Department of Psychiatry, Socialpsychiatry and Psychotherapy, Hannover Medical School, Hannover, Germany
6. Department of Addictive Disorders, Psychiatry and Psychotherapy, LVR-Klinik Cologne, Cologne, Germany
7. Clinic of Psychiatry and Psychotherapy, Ev. Klinikum Bielefeld, Bielefeld, Germany
8. LVR-Hospital Essen, Department of Psychiatry and Psychotherapy, Medical Faculty, University of Duisburg-Essen, Essen, Germany
9. Department of Psychiatry, Psychotherapy, Psychosomatic and Addiction Medicine, Kliniken Essen-Mitte, Essen, Germany