OPRM1 and alcohol drinking: Several studies on the effect of single nucleotide polymorphisms (SNPs) in OPRM1, such as rs1799971, on alcohol dependence report contradictory results.4, 5 Furthermore, the role of the κ‐opioid receptor in the regulation of reward stimuli via the modulation of dopaminergic tone8 has prompted research on the association of OPRK1 —which encodes the κ‐opioid receptor—with alcoholism.9 However, the role of OPRK1 in AUD is unclear due to conflicting results.10, 11