Genome-wide association of frequency of cannabis use

Cannabis is the most widely consumed psychoactive substance worldwide. Recent trends to decriminalize and medicalize cannabis will likely see consumption grow further. However, cannabis usage is not without risk, particularly relating to psychiatric outcomes. Although cannabis usage has been shown to be strongly heritable (40-48%, Verweij et al. 2010), the genetics are not well understood. After conducting and publishing meta-analyses of GWAS of both life-time cannabis usage, and age at first cannabis usage, we intend to follow these up by performing a genome-wide association study and meta-analysis of frequency of cannabis usage.