The problems of diagnosis and treatment of depressive states occupy one of the leading places in clinical psychiatry. Despite the fact that depression is a psychiatric disorder, the majority of depressive disorders are not in the field of vision of a psychiatrist, and these patients are observed by general practitioners. The textbook presents contemporary theoretical aspects of the etiopathogenesis of anxiety-depressive disorders and their classification. The features of depression diagnostics, variants of their comorbidity with somatic pathology are singled out among the patients of the general medical practice. Contemporary approaches to the therapy of sleep disorders in depression that are revealed in patients attending primary health care institutions are described. The textbook is intended for use in the curricula of medical universities and postgraduate medical education, as well as for practicing physicians psychiatrists, psychotherapists, neurologists, medical psychologists and doctors of general medical practice.