We studied the relationship between genes of serotonin transporter and brain-derived neurotrophic factor and parameters of AEP N100 wave to a non-significant stimulus in patients with endogenous mental diseases. In patients with endogenous psychoses, a significant effect of BDNF Val66Met marker on N100 wave amplitude was revealed: the mean N100 amplitude was higher in carriers of Val/Val genotype compared to Val/Met genotype carriers. The effect of the 5-HTTLPR marker on the wave amplitude was less pronounced (tendency): the SS genotype was associated with higher N100 amplitude.