Research in contextEvidence before this studyCannabis use disorder is heritable (50–70% according to twin and family studies), yet identification of genomic variants associated with cannabis use disorder from genome-wide association studies (GWASs) remains sparse. We surveyed all peer-reviewed journal publications in English on GWASs of cannabis use disorder or cannabis dependence using Google Scholar and PubMed, published between Jan 1, 1990, and April 1, 2020. Search terms included “cannabis dependence”, “cannabis abuse”, “cannabis use disorder”, “marijuana dependence”, “marijuana abuse”, “marijuana use disorder”, and “GWAS”. The most promising finding to date is a variant that is a cis-eQTL for CHRNA2 (Demontis and colleagues), which was replicated in an independent dataset for cannabis use disorder. Independently, GWAS of cannabis use have identified multiple genetic risk loci; however, the extent to which the genetics of cannabis use correlates with liability to cannabis use disorder has not been determined. Although GWASs of cannabis use have been studied in the context of a variety of psychiatric and psychosocial correlates, it is expected that some divergent associations will be seen when looking at cannabis use disorder.
