Camelia C Minică, Karin J H Verweij, Peter J van der Most, Hamdi Mbarek, Manon Bernard, Kristel R van Eijk, Penelope A Lind, Meng Zhen Liu, Dominique F Maciejewski, Teemu Palviainen, Cristina Sánchez-Mora, Richard Sherva, Michelle Taylor, Raymond K Walters, Abdel Abdellaoui, Timothy B Bigdeli, Susan J T Branje, Sandra A Brown, Miguel Casas, Robin P Corley, George Davey-Smith, Gareth E Davies, Erik A Ehli, Lindsay Farrer, Iryna O Fedko, Iris Garcia-Martínez, Scott D Gordon, Catharina A Hartman, Andrew C Heath, Ian B Hickie, Matthew Hickman, Christian J Hopfer, Jouke Jan Hottenga, René S Kahn, Jaakko Kaprio, Tellervo Korhonen, Henry R Kranzler, Ken Krauter, Pol A C van Lier, Pamela A F Madden, Sarah E Medland, Michael C Neale, Wim H J Meeus, Grant W Montgomery, Ilja M Nolte, Albertine J Oldehinkel, Zdenka Pausova, Josep A Ramos-Quiroga, Vanesa Richarte, Richard J Rose, Jean Shin, Michael C Stallings, Tamara L Wall, Jennifer J Ware, Margaret J Wright, Hongyu Zhao, Hans M Koot, Tomas Paus, John K Hewitt, Marta Ribasés, Anu Loukola, Marco P Boks, Harold Snieder, Marcus R Munafò, Joel Gelernter, Dorret I Boomsma, Nicholas G Martin, Nathan A Gillespie, Jacqueline M Vink, Eske M Derks
BACKGROUND AND AIMS: Cannabis is one of the most commonly used substances among adolescents and young adults. Earlier age at cannabis initiation is linked to adverse life outcomes, including multi-substance use and dependence. This study estimated the heritability of age at first cannabis use and identified associations with genetic variants. METHODS: A twin-based heritability analysis using 8055 twins from three cohorts was performed. We then carried out a genome-wide association meta-analysis of age at first cannabis use in a discovery sample of 24 953 individuals from nine European, North American and Australian cohorts, and a replication sample of 3735 individuals...
November 2018: Addiction