While there are a variety of reasons for the observed relationship between psychotic disorders and cannabis phenotypes (i.e., LCU and CUD), including shared environmental risk, mutual genetic risk is plausible. SCZ, BIP, LCU, and CUD are partly heritable (heritability range is 0.50–0.80)10–12 and emerging evidence has suggested a shared genetic component that increases the likelihood of both developing psychotic disorders and using cannabis. For instance, a modest positive genome-wide genetic correlation (rg, ranging from 0.17 to 0.31) has been reported between psychotic disorders and cannabis phenotypes,9,13 indicating genetic overlap. Although, more detailed genetic and mechanistic insights remain elusive.
