Reykjavik University, Reykjavik University, Planet Youth, Reykjavik University, Reykjavik University, Finnish Institute for Health and Welfare (THL), Finnish Institute for Health and Welfare (THL), Karolinska Institutet - Department of Medical Epidemiology and Biostatistics, University of Oslo - PROMENTA Research Center, Karolinska Institutet, Reykjavik University, Reykjavik University, Reykjavik University, Columbia University and Max Planck Society for the Advancement of the Sciences - Max Planck Institute for Psychological Research