Current existing problems of clinical psychiatry are considered in the aspect of most urgent and unresolved issues in the field of schizophrenia. Special attention is drawn to the differences in existing approaches to the classification of schizophrenia. In this connection, the author emphasizes the importance of the classification developed by A.V. Snezhnevsky and his school for theoretical and practical psychiatry. In view of this classification, the problem of clinical heterogeneity of schizophrenia related with the conception of different disease forms is considered. Difficulties of diagnosis of some forms and psychopathological evaluation of psychotic attacks developed in the continuous course of schizophrenia well as insufficient understanding of the problem of negative (deficit) symptoms and remission classification are discussed.