Schizophrenia is a severe, chronic, disabling mental disorder known to mankind throughout its history. The influence of various exogenous factors complicating the course of schizophrenia, one of which is the use of psychoactive substances, is of great importance. Patients with schizophrenia with pathomorphosis of clinical picture of disease in connection with their use of new psychoactive substances (NPS) represent a separate problem. The textbook describes the historical and current theoretical concepts of comorbidity in these nosologies. This textbook is based on the results of a study that analyzed the impact of NPSAs on the clinical and dynamic features of different stages of schizophrenia. The general signs and tendencies of course of disease are revealed, which analysis allowed to develop an algorithm of selection of adequate therapy and effective measures of secondary prevention.The guidelines are intended for practicing psychiatrists and narcologists, as well as for use in the curricula of medical universities and postgraduate medical education.