[1] Univ Gothenburg, Dept Psychol, Box 500, SE-40530 Gothenburg, Sweden
[2] Univ Gothenburg, Inst Neurosci & Physiol, Sahlgrenska Acad, Dept Psychiat & Neurochem, Gothenburg, Sweden
[3] Stockholm Ctr Dependency Disorders, Lifestyle Treatment Unit, Stockholm, Sweden
[4] Karolinska Inst, Dept Clin Neurosci, Stockholm, Sweden
[5] Karolinska Inst, Dept Med Epidemiol & Biostat, Stockholm, Sweden