Schizophrenia is a common and socially significant mental disorder requiring long-term use of antipsychotics (APs). Long-term use of APs increases the risk of developing adverse drug reactions (ADRs) and / or treatment resistance in some patients. This may be due to a genetically determined impairment of APs transport across the blood-brain barrier (BBB) and the membrane of APs target neurons in the brain. Pharmacogenetic testing (PGx) is a method to identify a group of patients with a high risk of developing AP-induced ADRs. Foreign panels for PGx do not include non-functional variants of genes encoding APs transporter proteins. However, our experience ofusing PGx to search for low-functional and non-functional single-nucleotide variants (SNVs)/polymorphisms of three genes (ABCB1, ABCG2, ABCC1) encoding APs transporter proteins demonstrates the importance of this new personalized approach to the choice of APs and its dosing in patients with a slow transporter PGx profile. The main purpose of the work is to present the experience of using pharmaco-genetic testing (PGx) in a 32-year-old patient with treatment-resistant schizophrenia and a medical history of AP-induced ADRs.