Genome-wide association study identifies a potent locus associated with human opioid sensitivity.
Nishizawa D, Fukuda K, Kasai S, Hasegawa J, Aoki Y, Nishi A, Saita N, Koukita Y, Nagashima M, Katoh R, et al. Mol Psychiatry. 2014 Jan; 19(1):55-62. Epub 2012 Nov 27.