Written by global experts, this book provides a modern comprehensive insight into the pharmacogenetics of treatment of major psychoses: schizophrenia, bipolar disorder and depression. The pharmacogenomics of three categories of the most important psychiatric drugs, antipsychotics, antidepressants and mood stabilizers, has been updated and reviewed. Some promising directions and perspectives for future research in pharmacogenetics in major psychoses are indicated. They are, among others, connected with the development of new methods in molecular genetics and with linking pharmacogenetics assessment with biomarkers, including neuroimaging ones. Finally, the attempts to use pharmacogenetics of antipsychotic, antidepressant and mood-stabilizing drugs in practice are presented. New pharmacogenetic tools may greatly contribute to introducing personalized medicine into psychiatric clinical practice.