evidence does not support a significant role in opioid dependence liability for this SNP, its potential involvement in the pathophysiology of other addictive disorders continues to be actively investigated (Ray et al. 2011). Overall, no associations involving OPRM1 SNPs have been consistently replicated; preliminary findings include reports of association with a greater positive response to heroin (Zhang et al. 2007) and risk for heroin dependence (Zhang et al. 2006; Levran et al. 2008).
