Dopamine Gene Variants in Opioid Addiction: Comparison of Dependent Patients, Nondependent Users and Healthy Controls

Aim: To determine whether specific dopaminergic system gene variants are associated with opioid dependence. Patients & methods: Subjects included 153 healthy controls, 163 opioid exposed, but not dependent and 281 opioid dependent. Genotypes of 90 variants in 13 genes were examined. Results: The most significant results were obtained for DA β-hydroxylase variants, rs2073837 and rs1611131, which were associated with protection from addiction (q = 0.0172, 0.0415, respectively) and the functional TH variant, rs2070762, was associated with more risk (q = 0.0387). The three variants also showed a combined effect that remained significant after correction for multiple testing (pfinal = 0.0039). Conclusion: These data offer support that dopaminergic gene variants have a role in opioid dependence and warrant further study.