Objectives:
Evidence suggests that decreased dopamine secretion in mesocorticolimbic pathways could predispose to increased susceptibility to substance addiction. It has been proposed to define such a phenomenon as the reward deficit syndrome (RDS). Dopaminergic projections of the reward system receive glutaminergic projections from cortex. Research indicates that a reduction in the stimulating glutamatergic transmission on the dopaminergic system could represent an alternative phenotype of RDS. Potential source of this type of abnormality is glutamate reuptake which depends on excitatory amino acid transport proteins (EAAT) function. The most important of them is EAAT2, polymorphisms of which have been linked to several mental disorders.

Methods:
We analyzed the genetic and psychometric data of 125 young adults (n = 125) for the effect of the rs4354668 polymorphism of the SLC1A2 gene for EAAT2 on the risky or harmful drug use (RHDU). After exploratory analysis we used logistic regression models to assess the probability of RHDU in individual groups.

Results:
In the final model T/T variant of rs4354668 was significantly associated with a lower probability of RHDU occurrence compared to G/G variant (OR: 0.021; 95% CI: 0.001 - 0.275; p = 0.009). Other significant predictors of RHDU were smoking status and risky or harmful drinking of alcohol.

Conclusions:
The results obtained may indicate a possible relationship of the risk of harmful drug use with variants of the rs4354668 polymorphism of the SLC1A2 gene for EAAT2. Subjects with the T/T variant of this polymorphism appear to be less at risk of developing drug use disorders.