Bipolar affective disorder (BPS) is a common and socially significant mental disorder that requires long-term use of psychotropic drugs (PDs). Long-term use of PDs increases the risk of developing adverse drug reactions (ADRs) and/or therapeutic resistance in some patients. This may be due to a genetically determined impairment of PDs metabolism by cytochrome P450 enzymes. Pharmacogenetic testing (PGx) is a method to identify a group of patients with a high risk of developing PDs -induced ADRs. Our experience of using PGx to search for low-functional and non-functional single nucleotide variants (SNVs) / polymorphisms of the CYP1A2, CYP2C8, CYP3A4, CYP3A5 and CYP2D6 genes encoding cytochrome P450 enzymes involved in PDs metabolism demonstrates the importance of this new personalized approach to the choice of PDs and its dosing in patients with pharmacogenetic profile poor metabolizer. The main purpose of the case report is to present the experience of using PGx in the therapy of dipolar affective disorder.