The article reflects the stages of development of views on schizotypal disorder (STD) in adults and children from the prenosological period to the present. It is shown how, after the recognition by the majority of psychiatrists of the concept of early dementia proposed by E. Kraepelin, there is a gradual recognition of the single essence of schizophrenia for childhood and adulthood, but with different, specific clinical manifestations at different age periods. The study of variants of schizophrenia without a fatal outcome in dementia, which led to the isolation of sluggish schizophrenia, including in childhood, begins with the works of E. Bleuler. The differences in approaches to the study and interpretation of sluggish schizophrenia in Russian, European and American psychiatry, which led to the isolation of STEs in the framework of personality disorders, are described. Three main concepts that exist at the present stage of research are presented, in which STD is considered as an independent disease in the spectrum of schizophrenic disorders, as one of the types of personality deviations with a high degree of vulnerability for the development of schizophrenia, and as one of the forms of the disease.