Mood disorders are the most common psychiatric disorders. According to epidemiological studies, the prevalence of unipolar depression among the general population is 2-7%, while the risk of this disorder during life is 5-17% 1-3 . The total prevalence of Bipolar Spectrum Disorders is 0.5-1.5%, and the chance of occurrence during life is about 5% 1-3 . The choice of a rational and appropriate treatment is essential. This article describes the principles of pharmacotherapy of Bipolar Disorder, particularly bipolar depression. The role of anticonvulsants as drugs of choice in the treatment of this disorder is described in details. Special attention is paid to the effectiveness of lamotrigine.