Further evidence for association ofGAL,GALR1 andNPY1R variants with opioid dependence

Aim:Heroin addiction is a chronic, relapsing disease that has genetic and environmental, including drug-induced, contributions. Stress influences the development of addictions. This study was conducted to determine if variants in stress-related genes are associated with opioid dependence (OD).Patients & methods:One hundred and twenty variants in 26 genes were analyzed in 597 Dutch subjects. Patients included 281 OD in methadone maintenance with or without heroin-assisted treatment and 316 controls.Results:Twelve SNPs in seven genes showed a nominally significant association with OD. Experiment-wise significant associations (p < 0.05) were found for three SNP pairs, through an interaction effect:NPY1R/GALrs4691910/rs1893679,NPY1R/GALrs4691910/rs3136541 andGALR1/GALrs9807208/rs3136541.Conclusion:This study lends more evidence to previous reports of association of stress-related variants with heroin dependence.