Two first works of swiss psychiatrist E. Bleuler that revise the symptomatology of Kraepelinian dementia praecox leaning on some findings of the psychoanalysis of S. Freud, C. Jung, F. Riklin, K. Abraham and on the P. Janet’s concept of psychasthenia are analyzed. The early concept of primary (testifying the direct organic lesion) and secondary (of psychogenic origin) symptoms of schizophrenia formulated by E. Bleuler is compared with his following concept of «basic» and «accessory» symptoms of schizophrenia. The concept of primary and secondary symptoms of schizophrenia was created firstly as a ground for the prognosis of the disease, and the concept of basic and accessory symptoms for the confident diagnosis of the disease. E. Bleuler’s concept accentuated the diagnosis of schizophrenia on the psychopathological and pathopsychological state of the patient, in contrast to E. Kraepelin’s concept of dementia praecox based on the course and outcome, made possible the expansion of schizophrenia boundaries at the expense of different psychotic and nonpsychotic disorders that other authors attributed to the forms of «degenerative madness», neuroses and psychopathies.