1. SERAF-Norwegian Centre for Addiction Research, University of Oslo, Oslo, Norway.
2. Medical University, Vienna, Department of Psychiatry and Psychotherapy, Vienna, Austria.
3. University of Maryland, College Park, College Park, MD, USA.
4. Recovery Pathways, Bay City, MI, USA.
5. Central Michigan University, College of Medicine, Departments of Family Medicine and Psychiatry, Saginaw, MI, USA.
6. Substance Abuse Treatment Evaluations and Interventions Research Program, RTI International, Research Triangle Park, NC, USA, and Departments of Psychiatry and Behavioral Sciences and Obstetrics and Gynecology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.