Polymorphisms in the catechol-O-methyltransferase gene (COMT)—an enzyme involved in dopamine metabolism and some forms of psychosis (Silveira et al., 2016)—are linked with cannabis dependence, as well as THC-induced impairments in working memory (Tunbridge et al., 2015) and executive functions (Verdejo-Garcia et al., 2007). Here, COMT is linked to cannabis dependence.