The textbook is based on training programs for students of medical universities in Ukraine, Belarus and Russia and programs of pre-certification cycles in psychiatry, child psychiatry and narcology. All the main sections of diagnosis, differential diagnosis, therapy of mental disorders, including psychotherapy, as well as the history of psychiatric science are presented. For the first time, the manual introduced chapters for analyzing the behavior and speech of patients, ethnic psychiatry, described the features of doctor and patient communications and psychopathology associated with psychic perception. All sections are illustrated with case histories. Diagnostic scales are displayed in the appendix.