The identification of genes that specifically relate to the action and metabolism of exogenous cannabinoids is limited by the paucity of research in this area – most of the research draws heavily on parallels between the activity of endogenous cannabinoids and the presumed action of THC and other exogenous cannabinoids. The identification of cannabinoid receptors is an ongoing research effort, with the possibility of there being unknown receptors. We focus on 6 genes, two of which have been actively studied and the remainder that are leading contenders to explain individual differences in liability to cannabis use disorders. The majority of association studies conducted with these genes has been exploratory – hence, here we review all human association studies that have investigated the effects of these genes on any substance-related measure.
