Pharmacogenetic testing of MDR1 (C3435T), CYP2D6, CYP1A2, and CYP2C19 genotypes distribution was performed in for treatment of patients resistant to antipsychotic treatment. It was found out that the frequency of patients with MDR1 T/T genotype coding synthesis of inactive p-glycoprotein was increased in comparison with group of Russian population. Decreased frequency of normal metabolizes of CYP1A2 was also revealed. No statistically significant changes in CYP2D6, and CYP2C19 genotypes distribution was revealed in patient resistant to antipsychotic treatment. It was suggested that MDR1 (C3435T) testing implementation in psychiatry can increase efficacy of treatment with antipsychotics (4 tables, bibliography: 41 refs).