SLC6A3 and alcohol abuse: In the same study, a composite score including the polymorphism of the DAT1/SLC6A3 gene and functional polymorphisms of catechol-O-methyl-transferase (COMT), DRD2, and DRD4 genes, supported a moderator effect on the medication: aripiprazole reduced the primary outcomes more in patients with alcohol use disorder who carried a larger number of genes associated with higher synaptic dopamine tone (83).