OBJECTIVE: The aim of the study was to determine relationships between the selected DRD2 gene polymorphisms and drug addiction.
METHODS: One hundred drug abusers undergoing treatment were recruited from the inpatient psychiatric centers in Poland. All participants were screened by means of the clinical interview SSAGA to describe the clinical picture. In the second part of the study, participants were examined using psychometric tools assessing selected psychopathological features. After that, blood samples were collected for a DNA isolation. The following DRD2 single nucleotide polymorphisms (SNPs) of the dopamine gene were genotyped: rs1800498 polymorphism of DRD2 gene (NC_000011.10:g.113420866G>A, GRCh38.p7); rs1079597 polymorphism of DRD2 gene (NC_000011.10:g.113425564C>T, GRCh38.p7); rs1076560 polymorphism of DRD2 gene (NC_000011.10:g.113412966C>A, GRCh38.p7).
RESULTS: The rs1800498 polymorphism has shown an association with drug abuse in which a higher frequency of the allelic T form was observed in the whole group of patients and selected subgroups with concomitant opiates or cannabis abuse history when compared with the controls.
CONCLUSIONS: In the presented study, one of selected polymorphisms of DRD2 gene, revealed to be correlated with substance use disorder (at the limit of statistical significance), which could suggest its impact on dependence endophenotype. The presented research was a pilot study, so it requires replication on a larger group of patients to verify and confirm obtained outcomes.

BACKGROUND: The aim of this study was to analyze the possible association of polymorphic variants of the DRD2 and ANKK1 genes with suicide attempt in a Mexican population.
METHODS: We conducted a case-control study in 289 subjects (166 suicide attempters and 123 healthy controls). We genotyped 2 polymorphisms of DRD2 (rs6275 and rs1799978) and 1 polymorphism of ANKK1 (rs1800497); then we analyzed the association between suicide attempt and these polymorphisms through genotypes, alleles, and inheritance models.
RESULTS: Individuals who carried the TT genotype of the rs1800497 showed a 3-fold risk of attempting suicide (OR = 3.01; 95% CI 1.56-5.81, p = 0.001) when evaluated through the recessive model. In an analysis stratified by gender, this risk factor remained present among females (OR = 2.81; 95% CI 1.37-5.75) as well as males (OR = 3.3; 95% CI 1.01-10.77).
CONCLUSIONS: Our results suggest that the rs1800497 variant of the ANKK1 gene could increase the risk of suicide attempt in a Mexican population. However, further studies using larger samples are necessary to obtain more conclusive results.