Effects of PDYN 68-bpVNTR, BDNF rs6265, OPRD1 rs569356 and OPRM1 rs2075572 polymorphisms on opioid-methamphetamine co-use.

To investigate the impact of PDYN 68-bpVNTR, BDNF rs6265, OPRD1 rs569356 and OPRM1 rs2075572 variations on the susceptibility to opioid-methamphetamine co-use, a total of 532 individuals, including opioid (n = 104), and methamphetamine (n = 166) users as well as opioid and methamphetamine co- users (n = 158) and healthy individuals (n = 104), were included. BDNF rs6265, OPRD1 rs569356 and OPRM1 rs2075572 were genotyped by PCR-RFLP method, while PDYN 68-bp VNTR was genotyped by PCR. The assessment of impulsiveness, craving, withdrawal, anxiety and depressive symptoms was conducted using scales. A significant difference was identified between the substance-using groups and the control group in view of the alleles of PDYN 68-bp VNTR (p = 0.001). The allele frequencies of the PDYN 68-bp VNTR exhibited a difference between opioid and methamphetamine users (p = 0.018). The 5-repeat allele was first observed in the Turkish population. The analysed polymorphisms could contribute to the development of addiction, exerting an influence on impulsiveness, craving and withdrawal.