Association between Novelty Seeking of opiate-dependent patients and the catechol-O-methyltransferase Val¹⁵⁸Met polymorphism

Background: Candidate genes of the dopaminergic system have been reported as key elements in shaping human temperament. Catechol-O-methyltransferase (COMT) plays a vital role in dopamine inactivation, and the Val¹⁵⁸Met single nucleotide polymorphism (rs4680) in its gene has been recently associated with the Novelty Seeking (NS) temperament scale of the Temperament and Character Inventory in studies of healthy adults, as well as methamphetamine abusers. 

Method: Our goal was to examine the association between temperament dimensions of the Temperament and Character Inventory and the COMT Val ¹⁵⁸Met variation in a Hungarian sample of 117 heroin-dependent patients and 124 nondependent controls. 

Results: Case-control analysis did not show any significant difference in allele or genotype distributions. However, dimensional approach revealed an association between the COMT Val ¹⁵⁸Met and NS (P = .01): both controls and opiate users with Met/Met genotypes showed higher NS scores compared to those with the Val allele. The NS scores are also significantly higher among opiate users; however, no interaction was found between group status and COMT genotype. 

Conclusion: Association of the COMT polymorphism and NS temperament scale has been shown for heroin-dependent patients and controls regardless of group status.