Addiction to heroin and other opioid drugs is a growing public health concern (Substance Abuse and Mental Health Service Administration, 2013) with profound economic consequences (Mark et al., 2001). Heroin addiction is heritable (Mistry et al., 2014), and although a few single nucleotide polymorphisms (SNPs) in the opioid receptor genes OPRM1 (Hancock et al., in press) and OPRD1 (Nelson et al., 2014) have been reproducibly associated, the specific genetic variants contributing to heroin addiction remain largely unknown.
