1. Department of Psychology, University of Gothenburg, Gothenburg, Sweden
2. Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
3. Stockholm Center for Dependency Disorders, Lifestyle Treatment Unit, Stockholm, Sweden
4. Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
5. Department of Medical Epidemiology and Biostatics, Karolinska Institutet, Stockholm, Sweden