Genetic factors are known major determinants of addiction, while dopamine is known tobe involved in reward and motivation.13,26 Changes in dopaminergicsignaling may therefore be expected to influence individual tendencies to addiction.We have, in this study, examined the relationships between a known polymorphism ofthe DAT1 gene coding for a key protein in the dopaminergic signaling pathway,cannabis use, and cannabis dependence among patients receiving treatment forcannabis use disorders at a tertiary treatment facility within Lagos in Nigeria. The gene discussed is SLC6A3; the disease is cannabis dependence.